feat: extract in-process MCP action layer, concurrent task dispatch, and spawn/reconcile hardening

- Extract device action execution into artemis/mcp action layer:
  typed ActionResult, capability manifest with startup validation,
  AdbActuator as the single physical implementation, in-memory
  ActionSession (replaces stdio subprocess MCP in validator), and
  McpActionExecutor preserving the legacy executor contract.
  adb_server keeps its external stdio/SSE surface unchanged and now
  reuses the actuator implementation; import-time side effects moved
  into configure_stdio_mode().
- Capability-gated prompt assembly (prompt_assembly.py): tool enums and
  teaching segments render per available backend tools; full-set output
  is byte-identical to the previous static text (locked by tests).
- Admin console task queue: serial worker replaced by a per-device
  concurrent dispatcher (ARTEMIS_CONCURRENCY_MODE=global restores
  serial semantics), per-session cancellation, strict device binding on
  enqueue, unified stdio piping with tee to trace stdout.log, and
  shutdown cleanup of all active runs. Fix _pid_exists exception order
  so PermissionError is treated as alive.
- mcp_server reliability: spawn watchdog kills runners stuck before
  interpreter startup and releases device reservations; task state
  reconcile uses psutil liveness, prefers runner-reported pids, and
  adds a 45s startup grace to stop false failure reports on Windows;
  conversation_id is now optional end-to-end; explicit device_serial is
  validated at submission.
- CLI install now writes ~/.claude/rules/artemis.md for Claude Code and
  migrates/removes the legacy CLAUDE.md injection block; ~/.claude.json
  is never rewritten when it fails to parse.
- Tests: Windows-portable stdio lifecycle and path assertions; new
  suites for action layer, prompt assembly, spawn watchdog, and task
  reconcile (895 passed, 3 skipped).

README.md

@@ -185,7 +185,7 @@ To ensure your AI coding assistant acts with the rigor of a senior mobile test e
 
 You can mount or copy [`mcp_server/rules.md`](./mcp_server/rules.md) into your AI IDE's rule configuration:
 * **Antigravity**: Add the contents of `rules.md` to your Workspace Rules, Global Rules settings, or agent instructions.
-* **Claude Code**: Copy or include the contents of `rules.md` in your project's `CLAUDE.md` file.
+* **Claude Code**: Run `artemis mcp --install claude` to install the rules to `~/.claude/rules/artemis.md` (install to exactly one location — Claude Code loads both `~/.claude/CLAUDE.md` and `~/.claude/rules/*.md`, so duplicating the rules wastes context).
 * **Cursor**: Copy the contents into `.cursorrules` or create a rule file at `.cursor/rules/artemis.mdc`.
 * **Codex**: Add the contents to `~/.codex/AGENTS.md` (or the active `AGENTS.override.md`).
 * **Windsurf / OpenClaw**: Add the rules to your workspace rules or global system prompts.

README_CN.md

@@ -187,7 +187,7 @@ PYTHONPATH = "/path/to/artemis"
 
 你可以将 [`mcp_server/rules.md`](./mcp_server/rules.md) 挂载或复制到你的 AI IDE 规则配置中：
 * **Antigravity**：将 `rules.md` 内容添加至工作区规则（Workspace Rules）或全局规则设置中。
-* **Claude Code**：将 `rules.md` 内容复制或引入至项目根目录的 `CLAUDE.md` 文件中。
+* **Claude Code**：运行 `artemis mcp --install claude` 自动安装规则至 `~/.claude/rules/artemis.md`（只安装到单一位置——Claude Code 会同时加载 `~/.claude/CLAUDE.md` 与 `~/.claude/rules/*.md`，重复安装会浪费上下文）。
 * **Cursor**：将内容复制到 `.cursorrules` 文件或在 `.cursor/rules/artemis.mdc` 中创建新规则。
 * **Codex**：将内容添加至 `~/.codex/AGENTS.md`（或当前生效的 `AGENTS.override.md`）。
 * **Windsurf / OpenClaw**：将内容添加到工作区规则或全局 System Prompt 中。

apps/admin_console/core/state.py

@@ -19,6 +19,29 @@ from typing import Any
 from artemis.config import PAUSE_FILE
 
 
+def _pid_exists(pid: int) -> bool:
+    """Best-effort liveness probe; returns True when liveness cannot be determined.
+
+    psutil is preferred because on Windows ``os.kill(pid, 0)`` does not report
+    dead pids reliably.
+    """
+    try:
+        import psutil
+
+        return psutil.pid_exists(pid)
+    except Exception:
+        pass
+    try:
+        import os
+
+        os.kill(pid, 0)
+        return True
+    except PermissionError:
+        return True
+    except (ProcessLookupError, OSError):
+        return False
+
+
 class ServerState:
     """Encapsulates all runtime states of the debug server."""
 
@@ -40,6 +63,12 @@ class ServerState:
         self.cancelled_session_ids: set[str] = set()
         self.startup_progress: dict[str, list[dict[str, Any]]] = {}
 
+        # Concurrent task executions keyed by session_id. Each value holds
+        # {"process", "device_id", "goal", "profile"}. `current_process` /
+        # `active_session_id` mirror the most recently launched run for
+        # backward compatibility with single-task consumers.
+        self.active_runs: dict[str, dict[str, Any]] = {}
+
         # Unified single source of truth for task queue
         self.queue_items: list[dict[str, Any]] = []
         self._wake_event: asyncio.Event | None = None
@@ -101,8 +130,37 @@ class ServerState:
     def queue_goals(self, val: list[Any]):
         pass
 
+    def prune_finished_runs(self) -> None:
+        """Drop finished entries from active_runs.
+
+        Besides reaped processes (returncode set), also drops entries whose pid no
+        longer exists: if a run coroutine dies without reaping its child, the entry
+        must not permanently block the scheduler.
+        """
+        for sid, run in list(self.active_runs.items()):
+            proc = run.get("process")
+            if proc is None or proc.returncode is not None:
+                self.active_runs.pop(sid, None)
+                continue
+            pid = getattr(proc, "pid", None)
+            if pid and not _pid_exists(pid):
+                self.active_runs.pop(sid, None)
+
+    @property
+    def busy_device_ids(self) -> set[str]:
+        """Device serials currently owned by an in-flight run."""
+        self.prune_finished_runs()
+        return {
+            str(run["device_id"])
+            for run in self.active_runs.values()
+            if run.get("device_id")
+        }
+
     @property
     def is_running(self) -> bool:
+        self.prune_finished_runs()
+        if self.active_runs:
+            return True
         has_proc = False
         if self.current_process is not None:
             if self.current_process.returncode is not None:

apps/admin_console/routers/tasks.py

@@ -103,10 +103,15 @@ async def run_task(request: RunRequest):
 
     if device_probe and device_probe.metadata.get("active_device"):
         verified_serial = device_probe.metadata["active_device"].get("serial")
-        if verified_serial:
+        # Only auto-selected targets may be re-bound to the probed device. An
+        # explicitly requested serial is never silently replaced -- if it is
+        # invalid, enqueue_tasks rejects the submission with a clear error.
+        if verified_serial and not request.device_serial:
             target_serial = verified_serial
-            if readiness_engine.get_active_device_serial() != verified_serial:
-                readiness_engine.set_active_device_serial(verified_serial)
+        # The probe verified a live device either way: keep the global active
+        # serial in sync even when the caller pinned the target explicitly.
+        if verified_serial and readiness_engine.get_active_device_serial() != verified_serial:
+            readiness_engine.set_active_device_serial(verified_serial)
 
     return await task_queue_service.enqueue_tasks(
         incoming_goals,

apps/admin_console/server.py

@@ -147,6 +147,23 @@ async def on_shutdown():
             pass
     state.worker_task = None
 
+    # Cancel in-flight run coroutines and wait for their finalizers (DB status,
+    # session_ended broadcast, trace sync, recording recovery) to run.
+    run_tasks = [t for t in list(task_queue_service._run_tasks) if not t.done()]
+    for run_task in run_tasks:
+        run_task.cancel()
+    if run_tasks:
+        try:
+            await asyncio.wait_for(
+                asyncio.gather(*run_tasks, return_exceptions=True), timeout=5.0
+            )
+        except (TimeoutError, asyncio.CancelledError):
+            pass
+    for run in list(state.active_runs.values()):
+        run_proc = run.get("process")
+        if run_proc is not None and run_proc.returncode is None:
+            await task_queue_service._terminate_worker_process(run_proc)
+    state.active_runs.clear()
     if state.current_process is not None and state.current_process.returncode is None:
         await task_queue_service._terminate_worker_process(state.current_process)
     for item in state.queue_items:

apps/admin_console/services/task_queue_service.py

@@ -46,6 +46,10 @@ class TaskQueueService:
     and startup tasks.
     """
 
+    # Strong references to in-flight _execute_task_item tasks (asyncio itself only
+    # keeps weak references to running tasks).
+    _run_tasks: set[asyncio.Task] = set()
+
     @classmethod
     def _broadcast_event(cls, event_type: str, data: Any):
         """Broadcasts an event safely to all registered subscribers."""
@@ -128,39 +132,71 @@ class TaskQueueService:
         A new process group alone is insufficient on Windows: the worker still
         shares the parent's console, so a CTRL_C_EVENT generated anywhere in
         that console can reach the UI server. CREATE_NO_WINDOW removes that
-        shared console boundary. Output is captured and forwarded explicitly
-        so detached workers remain visible in the server terminal.
+        shared console boundary.
+
+        Output is captured on every platform so it can be forwarded to the
+        server terminal and teed into the trace's stdout.log (the daemon itself
+        is often spawned with its stdio discarded, so inheriting would lose the
+        worker's logs entirely).
         """
+        kwargs: dict[str, Any] = {
+            "stdout": asyncio.subprocess.PIPE,
+            "stderr": asyncio.subprocess.STDOUT,
+        }
         if sys.platform == "win32":
-            return {
-                "creationflags": (
-                    subprocess.CREATE_NEW_PROCESS_GROUP | subprocess.CREATE_NO_WINDOW
-                ),
-                "stdout": asyncio.subprocess.PIPE,
-                "stderr": asyncio.subprocess.STDOUT,
-            }
-        return {}
+            kwargs["creationflags"] = (
+                subprocess.CREATE_NEW_PROCESS_GROUP | subprocess.CREATE_NO_WINDOW
+            )
+        return kwargs
 
     @staticmethod
-    async def _forward_worker_output(stream: asyncio.StreamReader | None) -> None:
-        """Forward a detached Windows worker's combined output without corrupting UTF-8."""
+    async def _forward_worker_output(
+        stream: asyncio.StreamReader | None, log_path: str | None = None
+    ) -> None:
+        """Forward a worker's combined output without corrupting UTF-8.
+
+        When ``log_path`` is given, the output is also teed into that file so
+        the trace's advertised stdout.log actually exists for diagnostics.
+        """
         if stream is None:
             return
 
-        decoder = codecs.getincrementaldecoder("utf-8")(errors="replace")
-        while True:
-            chunk = await stream.read(4096)
-            if not chunk:
-                break
-            text = decoder.decode(chunk)
-            if text:
-                sys.stdout.write(text)
-                sys.stdout.flush()
+        log_file = None
+        if log_path:
+            try:
+                os.makedirs(os.path.dirname(log_path), exist_ok=True)
+                log_file = open(log_path, "w", buffering=1, encoding="utf-8", errors="replace")
+            except Exception as exc:
+                print(f"[QueueWorker] Could not open worker log file '{log_path}': {exc}")
 
-        tail = decoder.decode(b"", final=True)
-        if tail:
-            sys.stdout.write(tail)
+        def _emit(text: str) -> None:
+            sys.stdout.write(text)
             sys.stdout.flush()
+            if log_file is not None:
+                try:
+                    log_file.write(text)
+                except Exception:
+                    pass
+
+        try:
+            decoder = codecs.getincrementaldecoder("utf-8")(errors="replace")
+            while True:
+                chunk = await stream.read(4096)
+                if not chunk:
+                    break
+                text = decoder.decode(chunk)
+                if text:
+                    _emit(text)
+
+            tail = decoder.decode(b"", final=True)
+            if tail:
+                _emit(tail)
+        finally:
+            if log_file is not None:
+                try:
+                    log_file.close()
+                except Exception:
+                    pass
 
     @staticmethod
     async def _finish_output_forwarder(output_task: asyncio.Task[None] | None) -> None:
@@ -231,269 +267,386 @@ class TaskQueueService:
         except RuntimeError:
             pass
 
+    @classmethod
+    def _concurrency_mode(cls) -> str:
+        """Resolve the scheduler concurrency mode.
+
+        Mirrors DeviceExecutionLock's contract (ARTEMIS_CONCURRENCY_MODE /
+        ARTEMIS_MAX_CONCURRENT_TASKS):
+        - "global": strict serial -- one task at a time across all devices.
+        - "per_device": one task per device -- distinct devices run concurrently.
+        Defaults to per-device concurrency, matching the lock layer's default.
+        """
+        mode = os.environ.get("ARTEMIS_CONCURRENCY_MODE", "").strip().lower()
+        if mode in ("global", "serial", "1"):
+            return "global"
+        if mode in ("per_device", "device", "parallel", "0"):
+            return "per_device"
+        try:
+            if int(os.environ.get("ARTEMIS_MAX_CONCURRENT_TASKS", 0) or 0) == 1:
+                return "global"
+        except (TypeError, ValueError):
+            pass
+        return "per_device"
+
     @classmethod
     async def queue_worker(cls):
-        """Persistent, self-healing background worker loop processing tasks in FIFO order."""
-        print("[QueueWorker] Background worker loop initialized and running.")
+        """Persistent dispatcher scheduling pending tasks onto devices.
+
+        Scans the queue and launches each eligible task as an independent
+        coroutine. Admission is governed by _concurrency_mode(): "global" admits
+        one task at a time overall, "per_device" admits one task per device so
+        distinct devices execute concurrently. Per-device FIFO ordering and
+        cross-process mutual exclusion remain enforced by DeviceExecutionLock
+        inside each worker process.
+        """
+        print(
+            "[QueueWorker] Dispatcher initialized "
+            f"(concurrency mode: {cls._concurrency_mode()})."
+        )
         try:
             DeviceExecutionLock.cleanup_stale_locks()
         except Exception as exc:
             print(f"[QueueWorker] Initial stale lock cleanup notice: {exc}")
 
-        while True:
-            task_item = None
-            sess_id = None
-            goal = None
-            profile = "flash"
-            output_task: asyncio.Task[None] | None = None
-            try:
-                if state.is_running:
-                    await asyncio.sleep(0.2)
+        try:
+            while True:
+                try:
+                    cls._dispatch_pending_tasks()
+                except Exception as exc:
+                    print(f"[QueueWorker] Dispatch error: {exc}")
+                try:
+                    await asyncio.wait_for(state.wake_event.wait(), timeout=0.3)
+                    state.wake_event.clear()
+                except TimeoutError:
+                    pass
+        except asyncio.CancelledError:
+            print("[QueueWorker] Dispatcher received cancellation signal.")
+            for run in list(state.active_runs.values()):
+                run_proc = run.get("process")
+                if run_proc is not None and run_proc.returncode is None:
+                    await cls._terminate_worker_process(run_proc)
+            raise
+
+    @classmethod
+    def _dispatch_pending_tasks(cls) -> None:
+        """Launch every pending task admissible under the current concurrency mode."""
+        mode = cls._concurrency_mode()
+        state.prune_finished_runs()
+        if mode == "global" and state.is_running:
+            return
+
+        # Dispatched-but-not-yet-spawned runs are only visible as queue items in
+        # "running" state, so admission must count those too -- active_runs alone
+        # lags behind by the subprocess startup latency.
+        in_flight = [
+            i
+            for i in state.queue_items
+            if isinstance(i, dict) and i.get("status") == "running"
+        ]
+        busy_devices = state.busy_device_ids | {
+            str(i.get("device_serial")) for i in in_flight if i.get("device_serial")
+        }
+        dispatched_any = False
+        loop = asyncio.get_running_loop()
+        for item in list(state.queue_items):
+            if not (isinstance(item, dict) and item.get("status") == "pending"):
+                continue
+            sess_id = item.get("session_id")
+            if sess_id and str(sess_id) in state.cancelled_session_ids:
+                cls._remove_task(sess_id)
+                continue
+
+            device = item.get("device_serial")
+            if mode == "per_device":
+                # A task without a resolved device may bind to any serial, so it
+                # only launches on an otherwise idle scheduler; the device lock
+                # then allocates freely without contending against active runs.
+                if device is None and (state.active_runs or in_flight or dispatched_any):
+                    continue
+                if device is not None and str(device) in busy_devices:
                     continue
 
-                # 1. Fetch the next pending task
-                task_item = cls._get_next_pending_task()
-                if task_item is None:
-                    await asyncio.sleep(0.3)
-                    continue
+            item["status"] = "running"
+            dispatched_any = True
+            if device is not None:
+                busy_devices.add(str(device))
+            run_task = loop.create_task(cls._execute_task_item(item))
+            # Hold a strong reference: asyncio keeps only weak refs to running
+            # tasks, and a collected run would strand its queue item forever.
+            cls._run_tasks.add(run_task)
+            run_task.add_done_callback(cls._run_tasks.discard)
+            if mode == "global":
+                break
 
-                # 2. Extract and initialize task execution metadata
-                sess_id = task_item.get("session_id")
-                if sess_id and str(sess_id) in getattr(state, "cancelled_session_ids", set()):
-                    cls._remove_task(sess_id)
-                    continue
+    @classmethod
+    async def _execute_task_item(cls, task_item: dict[str, Any]) -> None:
+        """Run one queued task to completion in its own worker subprocess."""
+        sess_id = task_item.get("session_id")
+        run_key = str(sess_id) if sess_id else uuid.uuid4().hex
+        goal = task_item.get("goal")
+        profile = task_item.get("profile", "flash")
+        proc: asyncio.subprocess.Process | None = None
+        output_task: asyncio.Task[None] | None = None
+        try:
+            expected_output = task_item.get("expected_output")
+            enable_outputter = task_item.get("enable_outputter")
+            locked_app = task_item.get("locked_app_package") or task_item.get("locked_app")
+            app_path = task_item.get("app_path")
+            task_item["status"] = "running"
+            task_item["start_time"] = time.time()
 
-                goal = task_item.get("goal")
-                profile = task_item.get("profile", "flash")
-                expected_output = task_item.get("expected_output")
-                enable_outputter = task_item.get("enable_outputter")
-                locked_app = task_item.get("locked_app_package") or task_item.get("locked_app")
-                app_path = task_item.get("app_path")
-                task_item["status"] = "running"
-                task_item["start_time"] = time.time()
+            # A fresh launch clears a stale stop request from a previous task,
+            # matching the historical serial worker's per-task reset. Per-session
+            # stops are tracked in cancelled_session_ids and are unaffected.
+            state.was_stopped_manually = False
+            state.current_goal = goal
+            state.current_profile = profile
+            state.active_session_id = sess_id
 
-                state.current_goal = goal
-                state.current_profile = profile
-                state.active_session_id = sess_id
-                state.was_stopped_manually = False
+            cls._broadcast_startup_progress(
+                sess_id, "launching", "Starting the execution process"
+            )
 
-                cls._broadcast_startup_progress(
-                    sess_id, "launching", "Starting the execution process"
+            # Broadcast session_started so all connected clients know the task has started
+            cls._broadcast_event(
+                "session_started",
+                {
+                    "session_id": sess_id,
+                    "initial_goal": goal,
+                    "profile": profile,
+                    "device_serial": task_item.get("device_serial"),
+                },
+            )
+
+            test_name = f"web_{int(time.time())}_{run_key[:8]}"
+            env = os.environ.copy()
+            pythonpath_parts = [
+                str(WORKSPACE_ROOT),
+                str(WORKSPACE_ROOT / "apps" / "admin_console"),
+                str(WORKSPACE_ROOT / "apps" / "cloud_service"),
+                env.get("PYTHONPATH", ""),
+            ]
+            env["PYTHONPATH"] = os.pathsep.join([p for p in pythonpath_parts if p])
+            env["PYTHONUTF8"] = "1"
+            env["PYTHONUNBUFFERED"] = "1"
+            if state.ipc_port is not None:
+                env["ARTEMIS_IPC_PORT"] = str(state.ipc_port)
+            if sess_id:
+                env["ARTEMIS_SESSION_ID"] = str(sess_id)
+            env["ARTEMIS_TASK_INGRESS"] = str(task_item.get("ingress", "frontend"))
+            env["ARTEMIS_TASK_WORKER"] = "1"
+            queue_ticket = task_item.get("queue_ticket")
+            if queue_ticket:
+                env[DeviceExecutionLock.QUEUE_TICKET_ENV] = str(queue_ticket)
+
+            cmd = [
+                sys.executable,
+                "-m",
+                "artemis.main",
+                goal,
+                "--profile",
+                profile,
+                "--test-name",
+                test_name,
+            ]
+            if sess_id:
+                cmd.extend(["--session-id", str(sess_id)])
+            if expected_output:
+                cmd.extend(["--output-description", str(expected_output)])
+            if enable_outputter is not None:
+                cmd.append("--enable-outputter" if enable_outputter else "--disable-outputter")
+            if locked_app:
+                cmd.extend(["--locked-app", str(locked_app)])
+            if app_path:
+                cmd.extend(["--app-path", str(app_path)])
+            device_serial = task_item.get("device_serial")
+            if device_serial:
+                cmd.extend(["--device-serial", str(device_serial)])
+                env["ADB_DEVICE_SERIAL"] = str(device_serial)
+
+            print(
+                f"[QueueWorker] Starting task [{sess_id}]: '{goal}' (profile: {profile}, device: {device_serial or 'auto'}, outputter: {bool(expected_output or enable_outputter)})"
+            )
+            proc = await asyncio.create_subprocess_exec(
+                *cmd,
+                cwd=str(WORKSPACE_ROOT),
+                env=env,
+                **cls._subprocess_creation_kwargs(),
+            )
+            state.current_process = proc
+            task_item["pid"] = proc.pid
+            state.active_runs[run_key] = {
+                "process": proc,
+                "device_id": str(device_serial) if device_serial else None,
+                "goal": goal,
+                "profile": profile,
+            }
+            if sess_id:
+                try:
+                    from mcp_server.utils import trace_store
+
+                    st = trace_store.read_status(str(sess_id))
+                    if st:
+                        st["pid"] = proc.pid
+                        trace_store.write_status(str(sess_id), st)
+                except Exception:
+                    pass
+            cls._broadcast_startup_progress(
+                sess_id, "process_ready", "Execution process started"
+            )
+            ingress_type = str(task_item.get("ingress", "frontend"))
+            DeviceExecutionLock.transfer_reservation(
+                str(queue_ticket),
+                proc.pid,
+                description=f"{ingress_type} task: {goal[:120]}",
+                device_id=device_serial or "pending",
+                session_id=str(sess_id) if sess_id else None,
+                ingress=ingress_type,
+            )
+            # Forward the worker's combined output and tee it into the trace's
+            # stdout.log so the log paths advertised by the MCP API exist.
+            log_path = None
+            if sess_id:
+                try:
+                    from mcp_server.utils import trace_store
+
+                    log_path = trace_store.get_trace_stdout_log_path(str(sess_id))
+                except Exception:
+                    log_path = None
+            if isinstance(proc.stdout, asyncio.StreamReader):
+                output_task = asyncio.create_task(
+                    cls._forward_worker_output(proc.stdout, log_path)
                 )
 
-                # Broadcast session_started so all connected clients know the task has started
+            if sess_id and (
+                str(sess_id) in getattr(state, "cancelled_session_ids", set())
+                or state.was_stopped_manually
+            ):
+                print(
+                    f"[QueueWorker] Task [{sess_id}] was cancelled during launch. Terminating."
+                )
+                await cls._terminate_worker_process(proc)
+
+            # 3. Await subprocess completion
+            returncode = await cls._wait_for_worker_process(proc)
+            print(f"[QueueWorker] Task [{sess_id}] exited with returncode {returncode}")
+
+            manual_stop = state.was_stopped_manually or bool(
+                sess_id and str(sess_id) in state.cancelled_session_ids
+            )
+
+            # 4. Perform fallback database status update and notification
+            if sess_id:
+                current_status = session_repo.get_session_status(sess_id)
+                new_status, should_persist = cls._resolve_terminal_status(
+                    current_status,
+                    returncode,
+                    manual_stop,
+                )
+                if should_persist:
+                    session_repo.update_session_status(sess_id, new_status, time.time())
+                    print(f"[QueueWorker] Updated session {sess_id} status to '{new_status}'")
+                else:
+                    print(
+                        f"[QueueWorker] Preserved authoritative session {sess_id} "
+                        f"status '{new_status}'"
+                    )
+                try:
+                    from mcp_server.utils import trace_store
+
+                    if trace_store.read_status(str(sess_id)):
+                        canonical_mcp_status = "completed" if new_status in ("completed", "success") else new_status
+                        trace_store.update_trace_status(
+                            str(sess_id),
+                            canonical_mcp_status,
+                        )
+                except Exception:
+                    pass
+                rec_info = session_repo.get_video_recording_for_session(sess_id)
+                rec_status = (rec_info or {}).get("status")
+                recovered_video_path = None
+                if rec_status != "ready":
+                    try:
+                        video_rec_map = session_repo.get_video_recordings_map()
+                        video_idx = await asyncio.to_thread(media_service.build_video_index)
+                        recovered_url = await asyncio.to_thread(
+                            media_service.resolve_video_url,
+                            {"session_id": sess_id},
+                            video_rec_map,
+                            video_idx,
+                        )
+                        if recovered_url:
+                            session_repo.mark_recording_ready(sess_id, recovered_url)
+                            cls._broadcast_event(
+                                "recording_ready",
+                                {"session_id": sess_id, "video_url": recovered_url},
+                            )
+                            recovered_video_path = recovered_url
+                    except Exception as rec_err:
+                        print(f"[QueueWorker] Error attempting recording recovery: {rec_err}")
+
+                if not recovered_video_path and rec_status != "ready":
+                    recording_error = "Task worker exited before recording finalization completed"
+                    if session_repo.mark_recording_failed_if_pending(sess_id, recording_error):
+                        cls._broadcast_event(
+                            "recording_failed",
+                            {"session_id": sess_id, "error": recording_error},
+                        )
+
+                state.active_connections.pop(sess_id, None)
                 cls._broadcast_event(
-                    "session_started",
+                    "session_ended",
                     {
                         "session_id": sess_id,
-                        "initial_goal": goal,
-                        "profile": profile,
-                        "device_serial": task_item.get("device_serial"),
+                        "status": new_status,
+                        "was_stopped_manually": manual_stop,
                     },
                 )
 
-                test_name = f"web_{int(time.time())}"
-                env = os.environ.copy()
-                pythonpath_parts = [
-                    str(WORKSPACE_ROOT),
-                    str(WORKSPACE_ROOT / "apps" / "admin_console"),
-                    str(WORKSPACE_ROOT / "apps" / "cloud_service"),
-                    env.get("PYTHONPATH", ""),
-                ]
-                env["PYTHONPATH"] = os.pathsep.join([p for p in pythonpath_parts if p])
-                env["PYTHONUTF8"] = "1"
-                env["PYTHONUNBUFFERED"] = "1"
-                if state.ipc_port is not None:
-                    env["ARTEMIS_IPC_PORT"] = str(state.ipc_port)
-                if sess_id:
-                    env["ARTEMIS_SESSION_ID"] = str(sess_id)
-                env["ARTEMIS_TASK_INGRESS"] = str(task_item.get("ingress", "frontend"))
-                env["ARTEMIS_TASK_WORKER"] = "1"
-                queue_ticket = task_item.get("queue_ticket")
-                if queue_ticket:
-                    env[DeviceExecutionLock.QUEUE_TICKET_ENV] = str(queue_ticket)
-
-                cmd = [
-                    sys.executable,
-                    "-m",
-                    "artemis.main",
-                    goal,
-                    "--profile",
-                    profile,
-                    "--test-name",
-                    test_name,
-                ]
-                if sess_id:
-                    cmd.extend(["--session-id", str(sess_id)])
-                if expected_output:
-                    cmd.extend(["--output-description", str(expected_output)])
-                if enable_outputter is not None:
-                    cmd.append("--enable-outputter" if enable_outputter else "--disable-outputter")
-                if locked_app:
-                    cmd.extend(["--locked-app", str(locked_app)])
-                if app_path:
-                    cmd.extend(["--app-path", str(app_path)])
-                device_serial = task_item.get("device_serial")
-                if device_serial:
-                    cmd.extend(["--device-serial", str(device_serial)])
-                    env["ADB_DEVICE_SERIAL"] = str(device_serial)
-
-                print(
-                    f"[QueueWorker] Starting task [{sess_id}]: '{goal}' (profile: {profile}, device: {device_serial or 'auto'}, outputter: {bool(expected_output or enable_outputter)})"
-                )
-                proc = await asyncio.create_subprocess_exec(
-                    *cmd,
-                    cwd=str(WORKSPACE_ROOT),
-                    env=env,
-                    **cls._subprocess_creation_kwargs(),
-                )
-                state.current_process = proc
-                task_item["pid"] = proc.pid
-                if sess_id:
+                conversation_id = task_item.get("conversation_id") if task_item else None
+                if conversation_id or task_item.get("ingress") == "mcp":
                     try:
-                        from mcp_server.utils import trace_store
+                        from mcp_server.notifiers import notify
 
-                        st = trace_store.read_status(str(sess_id))
-                        if st:
-                            st["pid"] = proc.pid
-                            trace_store.write_status(str(sess_id), st)
-                    except Exception:
-                        pass
-                cls._broadcast_startup_progress(
-                    sess_id, "process_ready", "Execution process started"
-                )
-                ingress_type = str(task_item.get("ingress", "frontend"))
-                DeviceExecutionLock.transfer_reservation(
-                    str(queue_ticket),
-                    proc.pid,
-                    description=f"{ingress_type} task: {goal[:120]}",
-                    device_id=device_serial or "pending",
-                    session_id=str(sess_id) if sess_id else None,
-                    ingress=ingress_type,
-                )
-                if sys.platform == "win32" and isinstance(proc.stdout, asyncio.StreamReader):
-                    output_task = asyncio.create_task(cls._forward_worker_output(proc.stdout))
-
-                if sess_id and (
-                    str(sess_id) in getattr(state, "cancelled_session_ids", set())
-                    or state.was_stopped_manually
-                ):
-                    print(
-                        f"[QueueWorker] Task [{sess_id}] was cancelled during launch. Terminating."
-                    )
-                    await cls._terminate_worker_process(proc)
-
-                # 3. Await subprocess completion
-                returncode = await cls._wait_for_worker_process(proc)
-                print(f"[QueueWorker] Task [{sess_id}] exited with returncode {returncode}")
-
-                # 4. Perform fallback database status update and notification
-                if sess_id:
-                    current_status = session_repo.get_session_status(sess_id)
-                    new_status, should_persist = cls._resolve_terminal_status(
-                        current_status,
-                        returncode,
-                        state.was_stopped_manually,
-                    )
-                    if should_persist:
-                        session_repo.update_session_status(sess_id, new_status, time.time())
-                        print(f"[QueueWorker] Updated session {sess_id} status to '{new_status}'")
-                    else:
-                        print(
-                            f"[QueueWorker] Preserved authoritative session {sess_id} "
-                            f"status '{new_status}'"
+                        notify(
+                            conversation_id=conversation_id or "",
+                            message=f"Artemis autonomous task '{goal}' finished with status '{new_status}'.\nTrace ID: {sess_id}",
+                            title=f"Task {new_status.capitalize()}: {goal[:40]}",
+                            event_type=new_status,
+                            payload={
+                                "trace_id": sess_id,
+                                "session_id": sess_id,
+                                "status": new_status,
+                                "goal": goal,
+                            },
                         )
-                    try:
-                        from mcp_server.utils import trace_store
+                    except Exception as notif_err:
+                        print(f"[QueueWorker] Notification dispatch notice: {notif_err}")
 
-                        if trace_store.read_status(str(sess_id)):
-                            canonical_mcp_status = "completed" if new_status in ("completed", "success") else new_status
-                            trace_store.update_trace_status(
-                                str(sess_id),
-                                canonical_mcp_status,
-                            )
-                    except Exception:
-                        pass
-                    rec_info = session_repo.get_video_recording_for_session(sess_id)
-                    rec_status = (rec_info or {}).get("status")
-                    recovered_video_path = None
-                    if rec_status != "ready":
-                        try:
-                            video_rec_map = session_repo.get_video_recordings_map()
-                            video_idx = await asyncio.to_thread(media_service.build_video_index)
-                            recovered_url = await asyncio.to_thread(
-                                media_service.resolve_video_url,
-                                {"session_id": sess_id},
-                                video_rec_map,
-                                video_idx,
-                            )
-                            if recovered_url:
-                                session_repo.mark_recording_ready(sess_id, recovered_url)
-                                cls._broadcast_event(
-                                    "recording_ready",
-                                    {"session_id": sess_id, "video_url": recovered_url},
-                                )
-                                recovered_video_path = recovered_url
-                        except Exception as rec_err:
-                            print(f"[QueueWorker] Error attempting recording recovery: {rec_err}")
-
-                    if not recovered_video_path and rec_status != "ready":
-                        recording_error = "Task worker exited before recording finalization completed"
-                        if session_repo.mark_recording_failed_if_pending(sess_id, recording_error):
-                            cls._broadcast_event(
-                                "recording_failed",
-                                {"session_id": sess_id, "error": recording_error},
-                            )
-
-                    state.active_connections.pop(sess_id, None)
-                    cls._broadcast_event(
-                        "session_ended",
-                        {
-                            "session_id": sess_id,
-                            "status": new_status,
-                            "was_stopped_manually": state.was_stopped_manually,
-                        },
-                    )
-
-                    conversation_id = task_item.get("conversation_id") if task_item else None
-                    if conversation_id or task_item.get("ingress") == "mcp":
-                        try:
-                            from mcp_server.notifiers import notify
-
-                            notify(
-                                conversation_id=conversation_id or "",
-                                message=f"Artemis autonomous task '{goal}' finished with status '{new_status}'.\nTrace ID: {sess_id}",
-                                title=f"Task {new_status.capitalize()}: {goal[:40]}",
-                                event_type=new_status,
-                                payload={
-                                    "trace_id": sess_id,
-                                    "session_id": sess_id,
-                                    "status": new_status,
-                                    "goal": goal,
-                                },
-                            )
-                        except Exception as notif_err:
-                            print(f"[QueueWorker] Notification dispatch notice: {notif_err}")
-
-            except asyncio.CancelledError:
-                print("[QueueWorker] Task received cancellation signal.")
-                if state.current_process and state.current_process.returncode is None:
-                    await cls._terminate_worker_process(state.current_process)
-                break
-            except Exception as e:
-                print(f"[QueueWorker] Unexpected error executing task: {e}")
-                await asyncio.sleep(0.5)
-            finally:
-                await cls._finish_output_forwarder(output_task)
-                # 5. Clean up completed task from queue and reset execution state
-                if sess_id:
-                    cls._remove_task(sess_id)
+        except asyncio.CancelledError:
+            print(f"[QueueWorker] Task [{sess_id}] received cancellation signal.")
+            if proc is not None and proc.returncode is None:
+                await cls._terminate_worker_process(proc)
+            raise
+        except Exception as e:
+            print(f"[QueueWorker] Unexpected error executing task [{sess_id}]: {e}")
+        finally:
+            await cls._finish_output_forwarder(output_task)
+            # 5. Clean up the finished task and release this run's scheduling slot
+            if sess_id:
+                cls._remove_task(sess_id)
+                state.cancelled_session_ids.discard(str(sess_id))
+            state.cancelled_session_ids.discard(run_key)
+            state.active_runs.pop(run_key, None)
+            if proc is not None and state.current_process is proc:
                 state.current_process = None
+            if not state.active_runs:
                 state.active_session_id = None
                 state.current_goal = None
                 state.current_profile = None
                 state.was_stopped_manually = False
-                state.wake_event.set()
+            state.wake_event.set()
 
     @classmethod
     async def enqueue_tasks(
@@ -564,6 +717,38 @@ class TaskQueueService:
                     "total_queued": len(state.queue_tasks),
                 }
 
+        # Strict device binding: reject an explicitly requested serial that is not
+        # attached and authorized, instead of silently running on another device.
+        if device_serial:
+            try:
+                from artemis.runtime import device_pool
+
+                norm = DeviceExecutionLock._normalize_device_id
+                attached = {
+                    norm(d.serial): d.state
+                    for d in await device_pool.list_devices_async()
+                }
+            except Exception:
+                attached = None
+            # Empty enumeration (no adb / transient failure) skips validation so the
+            # task can proceed and fail downstream with a clear no-device error,
+            # mirroring mcp_server.tools.task_runner._validate_device_serial.
+            if attached and attached.get(norm(device_serial)) != "device":
+                dev_state = attached.get(norm(device_serial))
+                error_detail = (
+                    f"Device '{device_serial}' is not connected. "
+                    f"Attached devices: {sorted(attached) if attached else 'none'}."
+                    if dev_state is None
+                    else f"Device '{device_serial}' is attached but not ready (state: '{dev_state}')."
+                )
+                return {
+                    "status": "rejected",
+                    "error": error_detail,
+                    "tasks": [],
+                    "enqueued_count": 0,
+                    "total_queued": len(state.queue_tasks),
+                }
+
         for i, goal in enumerate(goals):
             sess_id = (session_id if (session_id and len(goals) == 1) else str(uuid.uuid4()))
             assigned_serial = device_serial
@@ -690,8 +875,22 @@ class TaskQueueService:
                             },
                         )
 
-            if state.current_process:
+            if state.active_runs or state.current_process:
                 state.was_stopped_manually = True
+            for run_key, run in list(state.active_runs.items()):
+                # Track the stop per run so each finalizer resolves its terminal
+                # status as cancelled even if the global flag is reset meanwhile.
+                state.cancelled_session_ids.add(str(run_key))
+                run_proc = run.get("process")
+                if run_proc is not None and run_proc.returncode is None:
+                    try:
+                        run_proc.kill()
+                    except Exception:
+                        pass
+            # active_runs entries are popped by each run's finalizer once the
+            # process exit is observed; clearing them here would free the device
+            # slots before the processes are actually gone.
+            if state.current_process:
                 try:
                     state.current_process.kill()
                 except Exception:
@@ -749,7 +948,25 @@ class TaskQueueService:
             else False
         )
         owner_pid = owner.pid if owner else None
-        local_pid = getattr(state.current_process, "pid", None)
+
+        # Resolve the locally-managed run for this target (concurrent scheduling
+        # keeps one subprocess per run in state.active_runs).
+        local_run = None
+        if target_sid:
+            local_run = state.active_runs.get(target_sid)
+        elif target_device:
+            local_run = next(
+                (
+                    run
+                    for run in state.active_runs.values()
+                    if run.get("device_id") and str(run["device_id"]) == target_device
+                ),
+                None,
+            )
+        elif len(state.active_runs) == 1:
+            local_run = next(iter(state.active_runs.values()))
+        local_proc = (local_run or {}).get("process") or state.current_process
+        local_pid = getattr(local_proc, "pid", None)
         is_local_owner = bool(owner_pid and local_pid and owner_pid == local_pid)
 
         running_item = next(
@@ -795,19 +1012,24 @@ class TaskQueueService:
             # Never fall back to a frontend PID while another process has an
             # owner record that is still being published or cannot be parsed.
             return False
-        elif owner is None and state.current_process and (
-            not target_sid or str(state.active_session_id) == target_sid
+        elif owner is None and local_proc is not None and (
+            local_run is not None
+            or not target_sid
+            or str(state.active_session_id) == target_sid
         ):
-            # The frontend worker can be stopped during its short initialization
-            # window before Agent acquires the global device lease.
-            state.was_stopped_manually = True
+            # The locally-managed worker can be stopped during its short
+            # initialization window before Agent acquires the device lease.
+            if target_sid:
+                state.cancelled_session_ids.add(target_sid)
+            else:
+                state.was_stopped_manually = True
             if local_pid:
                 try:
                     stopped = process_supervisor.terminate_tree(local_pid)
                 except Exception:
                     stopped = False
             try:
-                state.current_process.kill()
+                local_proc.kill()
                 stopped = True
             except Exception:
                 pass
@@ -849,10 +1071,14 @@ class TaskQueueService:
             return False
 
         if is_local_owner:
-            state.was_stopped_manually = True
-            state.current_process = None
             if stopped_session_id:
+                # Per-session cancellation: the run's own finalizer resolves the
+                # terminal status without affecting other concurrent runs.
                 state.cancelled_session_ids.add(str(stopped_session_id))
+            else:
+                state.was_stopped_manually = True
+            if local_proc is not None and state.current_process is local_proc:
+                state.current_process = None
 
         for sid, conn_info in list(state.active_connections.items()):
             if (stopped_session_id and str(sid) == str(stopped_session_id)) or (

artemis/agents/flash/flash_runner.md

@@ -15,7 +15,7 @@ You operate in a dynamic observation-reasoning-execution loop. **CRITICAL RULE:
 # 2. DYNAMIC ENVIRONMENT & TIME AWARENESS
 Keep in mind that the mobile device is an asynchronous, constantly evolving environment. However, your actions entail an inherent "turn latency" (a 3–7 second delay caused by model inference and network transmission between normal consecutive actions).
 - **State Drift & Progression Tolerance**: While you think, video playback advances, banners scroll, and web pages finish loading. If the latest observation has progressed further than expected (e.g., an ad automatically skipped or a redirect landed), **do not treat it as an error**. Adapt smoothly to the live screen in front of you.
-- **Timed Waiting & Transitions**: When facing mid-transition animations, loading spinners, required watch durations, or ad countdown timers, use the precise `wait_for_delay` command to allow time to pass or the UI state to stabilize. Some transition states are subtle and may even resemble a phone bug or system freeze; it is always advisable to wait first, and only consider retrying or choosing an alternative path if the state remains broken.
+{% if "wait_for_delay" in available_tools %}- **Timed Waiting & Transitions**: When facing mid-transition animations, loading spinners, required watch durations, or ad countdown timers, use the precise `wait_for_delay` command to allow time to pass or the UI state to stabilize. Some transition states are subtle and may even resemble a phone bug or system freeze; it is always advisable to wait first, and only consider retrying or choosing an alternative path if the state remains broken.{% endif %}
 - **Time-Sensitive Tasks & Transient UI**: First, you must understand that each of your decision turns takes several seconds of model inference and network delay, while the mobile device state is continuously changing. A target element that you see on the current screenshot (e.g., auto-dismissing overlays, temporary message bars, menus or control bars with short timeouts) may have already vanished by the time your physical click command reaches the device! This is one of the most common reasons why the UI does not change as expected after a single step. We call these **Time-Sensitive Tasks**.
   - *Mental Model*: When facing these tasks, any attempt to interact step-by-step (such as tapping once to wake up a menu/bar and waiting for the next turn to tap the target button) WILL fail because the element will auto-dismiss during your decision delay. You MUST combine the summon action on the trigger element (`Trigger`) and the target action (`Target`) into a single atomic sequence.
   - *Chained Execution*: Use `click_sequence(sequence=[[trigger_x, trigger_y], [target_x, target_y]])` in `0-1000` normalized scale to execute both taps consecutively with a 50ms delay, catching the transient element before the timeout closes it.
@@ -32,7 +32,7 @@ Keep in mind that the mobile device is an asynchronous, constantly evolving envi
 1. **Normalized Coordinates (`0-1000` Scale)**: Always use normalized `[x, y]` coordinates in `0-1000` scale for any location-based target (e.g., `target=[500, 600]` or `click_sequence=[[300, 400], [500, 600]]`).
 2. **Do not determine element coordinates based on guesswork.** If the element is visible in the screenshot but its coordinates are missing from the provided XML tree, please use the `ask_explorer` tool to locate the element first.
 3. **Screenshot Pruning Awareness**: To optimize speed, the system **prunes old intermediate screenshots from your history**—you only ever see the *latest* live screenshot and UI tree. Therefore, if you spot critical text in an earlier step that you will need later (e.g., verification codes, specific titles, search lists), **you must explicitly verbalize and write those details into your text thinking/notes** so they persist across turns.
-4. **App Launching**: To start or reset an application, always use `manage_app(action="launch", app_name="...")` or `action="stop"`. Do not manually swipe across home screens.
+{% if "manage_app" in available_tools %}4. **App Launching**: To start or reset an application, always use `manage_app(action="launch", app_name="...")` or `action="stop"`. Do not manually swipe across home screens.{% endif %}
 
 ---
 

artemis/agents/flash/runner.py

@@ -36,10 +36,8 @@ from langchain_core.messages import (
 from artemis.agents.flash.context_compressor import compress_flash_messages
 from artemis.agents.flash.summarizer import VisualStepSummarizer
 from artemis.agents.validator.tool_declarations import (
-    ACTION_TOOL_NAMES,
     ASK_EXPLORER_TOOL,
     CLICK_SEQUENCE_TOOL,
-    MobileActionExecutor,
     REPORT_TASK_STATUS_TOOL,
     VALIDATOR_TOOLS_DECLARATION,
     capture_screenshot_and_parse_ui,
@@ -51,6 +49,7 @@ from artemis.controllers.unified_controller import UnifiedMobileController
 from artemis.data_engine.trace import trace
 from artemis.graph.perception import _check_injected_instruction_file
 from artemis.graph.state import State
+from artemis.mcp.action_executor import McpActionExecutor
 from artemis.services.llm import (
     RobustChatModelWrapper,
     get_google_llm,
@@ -78,7 +77,7 @@ class FlashRunner:
             self.step_summarizer_cfg = StepSummarizerConfig()
 
         self.controller = UnifiedMobileController(ctx)
-        self.executor = MobileActionExecutor(ctx, self.controller)
+        self.executor = McpActionExecutor(ctx, self.controller)
         self.summarizer = (
             VisualStepSummarizer(ctx, model_name=self.step_summarizer_cfg.model)
             if self.step_summarizer_cfg.enabled
@@ -90,6 +89,14 @@ class FlashRunner:
         tools.insert(1, CLICK_SEQUENCE_TOOL)
         tools.append(ASK_EXPLORER_TOOL)
         tools.append(REPORT_TASK_STATUS_TOOL)
+        # With an actuator installed, drop declarations for device actions the
+        # backend does not implement (and append its extension tools); without
+        # one, the full historical declaration set is kept.
+        actuator = getattr(self.ctx, "actuator", None)
+        if actuator is not None:
+            from artemis.mcp.action_manifest import filter_declarations
+
+            tools = filter_declarations(tools, actuator, "flash")
         return tools
 
     def _prune_intermediate_screenshots(self, messages: list[BaseMessage]) -> None:
@@ -144,10 +151,15 @@ class FlashRunner:
             }
         )
 
-        # Render System Prompt
+        # Render System Prompt. Tool-teaching segments are gated on the available
+        # tool set so an absent tool leaves no trace in the prompt; until an actuator
+        # is wired in, the full manifest set reproduces the historical prompt.
         prompt_path = Path(__file__).parent / "flash_runner.md"
         prompt_template = prompt_path.read_text(encoding="utf-8")
-        system_prompt = Template(prompt_template).render(goal=self.goal)
+        available_tools = frozenset(t.name for t in tools_declaration)
+        system_prompt = Template(prompt_template).render(
+            goal=self.goal, available_tools=available_tools
+        )
 
         messages: list[BaseMessage] = [
             SystemMessage(content=system_prompt),
@@ -432,8 +444,12 @@ class FlashRunner:
                 try:
                     exec_result = await self.executor.execute(name, args, tc_id, state)
 
+                    # Dynamic dispatch set: manifest device actions plus any backend
+                    # extension tools, so extension steps are recorded like actions.
+                    action_names = self.executor.action_tool_names
+
                     post_img_bytes = exec_result.screenshot_bytes
-                    if not post_img_bytes and name in ACTION_TOOL_NAMES:
+                    if not post_img_bytes and name in action_names:
                         try:
                             controller = UnifiedMobileController(self.ctx)
                             screen_data = await controller.get_screen_data()
@@ -447,7 +463,7 @@ class FlashRunner:
 
                     # Record telemetry / step in DataEngine
                     recorded_step_id = None
-                    if self.ctx.data_engine and name in ACTION_TOOL_NAMES:
+                    if self.ctx.data_engine and name in action_names:
                         try:
                             if self.ctx.data_engine.current_step_id is None:
                                 self.ctx.data_engine.allocate_step_id()
@@ -517,7 +533,7 @@ class FlashRunner:
                             logger.warning(f"Error recording step in FlashRunner: {step_err}")
 
                     # ⚡ Non-blocking dispatch of objective visual transition summarizer
-                    if self.summarizer and name in ACTION_TOOL_NAMES:
+                    if self.summarizer and name in action_names:
                         action_sequence += 1
                         self.summarizer.dispatch(
                             step_number=action_sequence,

artemis/agents/operator/operator.py

@@ -114,6 +114,30 @@ class OperatorNode:
             logger.error(f"Failed to load operator prompts: {e}")
             self.prompts = {}
 
+    def _available_device_actions(self) -> frozenset[str]:
+        """Device actions the installed actuator backend provides.
+
+        Without an explicit ``ctx.actuator`` the full manifest set applies (the
+        default AdbActuator implements everything), so behavior is unchanged until a
+        partial backend is actually installed.
+        """
+        from artemis.mcp.action_manifest import (
+            OPTIONAL_ACTIONS,
+            REQUIRED_ACTIONS,
+            available_device_actions,
+        )
+
+        actuator = getattr(self.ctx, "actuator", None)
+        if actuator is not None and callable(getattr(actuator, "capabilities", None)):
+            try:
+                extension_names = frozenset(
+                    e.name for e in actuator.extensions() if "operator" in e.targets
+                )
+                return available_device_actions(actuator) | extension_names
+            except Exception as e:
+                logger.warning(f"Failed to read actuator capabilities: {e}")
+        return REQUIRED_ACTIONS | OPTIONAL_ACTIONS
+
     def _check_infinite_loop(self, state: State):
         subagent_calls = state.subagent_calls or []
         if len(subagent_calls) >= 3:
@@ -386,15 +410,9 @@ class OperatorNode:
 
             current_messages.append(response)
 
-            action_tool_names = [
-                "click",
-                "input_text",
-                "swipe",
-                "press_key",
-                "manage_app",
-                "wait_for_delay",
-                "long_press",
-            ]
+            # Manifest-driven, so a backend's extension actions are classified as
+            # turn-ending device actions without touching this file.
+            action_tool_names = sorted(self._available_device_actions())
 
             def normalize_name(name: str) -> str:
                 return name.split(":")[-1] if ":" in name else name
@@ -804,23 +822,24 @@ class OperatorNode:
 
         current_step_num = len(steps) + 1
 
-        # 5. Prepare Tools
-        click_tool = self._get_click_tool()
-        input_text_tool = self._get_input_text_tool()
-        swipe_tool = self._get_swipe_tool()
-        press_key_tool = self._get_press_key_tool()
-        manage_app_tool = self._get_manage_app_tool()
-        wait_for_delay_tool = self._get_wait_for_delay_tool()
-        long_press_tool = self._get_long_press_tool()
-
+        # 5. Prepare Tools. Device-action declarations are assembled against the
+        # installed actuator backend's capabilities: an action the backend does not
+        # implement is simply never declared (and the prompt assembly drops its
+        # teaching segments in lockstep).
+        available_actions = self._available_device_actions()
+        action_tool_factories = {
+            "click": self._get_click_tool,
+            "input_text": self._get_input_text_tool,
+            "swipe": self._get_swipe_tool,
+            "press_key": self._get_press_key_tool,
+            "manage_app": self._get_manage_app_tool,
+            "wait_for_delay": self._get_wait_for_delay_tool,
+            "long_press": self._get_long_press_tool,
+        }
         all_tools = [
-            click_tool,
-            input_text_tool,
-            swipe_tool,
-            press_key_tool,
-            manage_app_tool,
-            wait_for_delay_tool,
-            long_press_tool,
+            factory()
+            for name, factory in action_tool_factories.items()
+            if name in available_actions
         ] + self.tools
 
         if self._has_checker_feedback():

artemis/agents/operator/prompt_builder.py

@@ -39,12 +39,18 @@ class OperatorPromptBuilder:
     """Builds prompt messages and multimodal contents for the Operator Agent."""
 
     @classmethod
-    def build_system_message(cls, template_name: str = "main_template") -> str:
+    def build_system_message(
+        cls,
+        template_name: str = "main_template",
+        available_tools: frozenset[str] | None = None,
+    ) -> str:
         from artemis.agents.operator.prompts import apply_operator_prompt_contract
 
         prompts = load_operator_prompts()
         try:
-            return apply_operator_prompt_contract(prompts[template_name])
+            return apply_operator_prompt_contract(
+                prompts[template_name], available_tools=available_tools
+            )
         except KeyError as exc:
             raise ValueError(f"Unknown Operator template: {template_name}") from exc
 

artemis/agents/operator/prompts.py

@@ -33,21 +33,139 @@ from artemis.utils.task_tree import get_active_subgoal_hashes
 logger = get_logger(__name__)
 
 
-_LEGACY_TOOL_CALLING_RULE = """- **Tool Calling Iron Rule**: Do NOT submit a Turn-Ending Action at the same time (in the same tool-call list) as a Pre-Decision Exploratory Tool. You must first gather information (e.g., finding coordinates or diagnosing a state), manage ADB background tasks, or update memory notes. You can use pre-decision exploratory tools to complete this task. You will be prompted again with the tool's result, at which point you can output your final physical/turn-ending action."""
+from artemis.agents.prompt_assembly import (
+    gate_segment,
+    render_tool_enum,
+    resolve_available,
+)
 
-_TOOL_CALLING_RULE = """- **Tool Calling Contract**: Tools that return information needed for the decision (`ask_explorer`, `ask_diagnoser`, `video_analyzer`, `run_adb_command`, `manage_task`, `analyze_task_output`, `read_note`, `list_notes`, and `save_note`) are result-dependent Pre-Decision Tools. Do not submit them in the same tool-call list as a Turn-Ending Action; inspect their result first. The write-through tools `update_note` and `append_note` may accompany at most one Turn-Ending Action when their content is based entirely on evidence already available before that action. Never write an action's expected outcome as if it had already been observed."""
+_LEGACY_TOOL_CALLING_RULE = """- **Tool Calling Iron Rule**: Do NOT submit a Turn-Ending Action at the same time (in the same tool-call list) as a Pre-Decision Exploratory Tool. You must first gather information (e.g., finding coordinates or diagnosing a state), manage ADB background tasks, or update memory notes. You can use pre-decision exploratory tools to complete this task. You will be prompted again with the tool's result, at which point you can output your final physical/turn-ending action."""
 
 _LEGACY_TOOL_PROTOCOL = """1. **Pre-Decision Exploratory Tools**:
    - *What they are*: Helper/Subagent tools (such as `ask_explorer`, `ask_diagnoser`, `video_analyzer`), ADB command tools (`run_adb_command`, `manage_task`), and memory note tools (`read_note`, `list_notes`, `save_note`, `update_note`, `append_note`).
    - *How they work*: These tools gather details or update/read memory. When you invoke these tools, the framework will immediately execute them and return the results, allowing you to continue thinking and make your final decision.
 2. **Turn-Ending Actions**:"""
 
-_TOOL_PROTOCOL = """1. **Result-Dependent Pre-Decision Tools**:
-   - *What they are*: Helper/Subagent tools (`ask_explorer`, `ask_diagnoser`, `video_analyzer`), ADB/task tools (`run_adb_command`, `manage_task`, `analyze_task_output`), and memory tools whose result must be inspected (`read_note`, `list_notes`, `save_note`).
-   - *How they work*: Invoke these without a Turn-Ending Action, inspect the returned result, and then decide.
-2. **Write-Through Memory Tools**:
-   - `update_note` and `append_note` may run alongside at most one Turn-Ending Action only when recording facts already observed in the current context. If the note content depends on the action's result, wait for the next observation before writing it.
-3. **Turn-Ending Actions**:"""
+# --- Assembled tool references -------------------------------------------------------
+# The orderings below reproduce the historical prompt wording exactly; with the full
+# tool set the rendered output is byte-identical to the previous literals. See
+# artemis/agents/prompt_assembly.py for the assembly rationale.
+
+_PRE_DECISION_HELPER_TOOLS = ("ask_explorer", "ask_diagnoser", "video_analyzer")
+_PRE_DECISION_ADB_TOOLS = ("run_adb_command", "manage_task", "analyze_task_output")
+_PRE_DECISION_MEMORY_TOOLS = ("read_note", "list_notes", "save_note")
+_PRE_DECISION_ALL_TOOLS = (
+    _PRE_DECISION_HELPER_TOOLS + _PRE_DECISION_ADB_TOOLS + _PRE_DECISION_MEMORY_TOOLS
+)
+
+# The two device-action enumeration slots in operator.json (identical in both
+# templates), in their historical orders.
+_PHYSICAL_ACTIONS_ORDER = (
+    "click",
+    "input_text",
+    "swipe",
+    "press_key",
+    "manage_app",
+    "wait_for_delay",
+    "long_press",
+)
+_TURN_ENDING_ORDER = (
+    "click",
+    "swipe",
+    "input_text",
+    "long_press",
+    "press_key",
+    "manage_app",
+    "wait_for_delay",
+)
+
+_PHYSICAL_ACTIONS_SLOT = (
+    "Physical device actions (`click`, `input_text`, `swipe`, `press_key`,"
+    " `manage_app`, `wait_for_delay`, `long_press`)"
+)
+_TURN_ENDING_SLOT = (
+    "Turn-Ending Action (`click`, `swipe`, `input_text`, `long_press`,"
+    " `press_key`, `manage_app`, or `wait_for_delay`)"
+)
+
+# Self-contained instruction segments that teach a single tool. Removed wholesale when
+# the tool is unavailable, so nothing in the prompt dangles.
+_WAIT_FOR_DELAY_TRANSITIONS_SEGMENT = (
+    "- **Loading & Transitions**: When entering page transitions (e.g., app launching,"
+    " web page loading, or progress indicators), use `wait_for_delay` to let the screen"
+    " settle before executing target actions. Some transition states are difficult to"
+    " discern, such as a thin progress line at the top of the browser screen during"
+    " webpage loads. Before questioning whether an error has occurred, you can first"
+    " adopt a waiting strategy to see how the device state evolves. If the state"
+    " remains ambiguous after waiting, certain UI components might be malfunctioning or"
+    " failing to load; in this case, consider retrying the action or pivoting to an"
+    " alternative path.\n"
+)
+_WAIT_FOR_DELAY_INTERVAL_PARENTHETICAL = (
+    " (convert minutes to milliseconds accurately for `wait_for_delay`)"
+)
+_VIDEO_ANALYZER_TRANSIENT_SEGMENT = (
+    "   - *Missed Transient States*: If the current state jumped ahead and you suspect"
+    " you missed an important initial or intermediate screen (e.g., a number or flash"
+    " message that was overwritten by your last action), consider using the"
+    " `video_analyzer` tool to look back at the recent history.\n"
+)
+_VIDEO_ANALYZER_SNAPSHOT_SENTENCE = (
+    " If you have already missed certain critical information and cannot re-view it by"
+    " going back or other operations, you can use the `video_analyzer` to look back at"
+    " historical information."
+)
+# Tail of the "Action Scope & Interaction Precision" bullet: everything past the two
+# generic gesture-scope sentences is swipe/drag teaching.
+_SWIPE_PRECISION_SEGMENT = (
+    " For any task requiring continuous range interactions, sliding, or boundary"
+    " selection, prefer using targeted swipe/drag gestures spanning from the element's"
+    " start bounds [xmin, ymin] to end bounds [xmax, ymax] to ensure the action is"
+    " strictly confined to the target element. For drag-and-drop, list reordering, or"
+    " sliding sliders/SeekBars, set duration >= 1000 (e.g. 1500) and always drag"
+    " slightly PAST the target position to overcome touch slop and reliably trigger the"
+    " drop/snap/value update. When setting a slider to Maximum (100%) or Minimum (0%),"
+    " always swipe fully to the extreme boundary to guarantee reaching the absolute"
+    " limits."
+)
+
+#: Every tool name the operator prompt slots can reference. ``available_tools=None``
+#: resolves to this set, preserving the historical output.
+OPERATOR_PROMPT_TOOLSET: frozenset[str] = frozenset(
+    _PRE_DECISION_ALL_TOOLS + _PHYSICAL_ACTIONS_ORDER
+)
+
+
+def _tool_calling_rule(available: frozenset[str]) -> str:
+    tools = render_tool_enum(_PRE_DECISION_ALL_TOOLS, available, final_sep="and")
+    return (
+        "- **Tool Calling Contract**: Tools that return information needed for the"
+        f" decision ({tools}) are result-dependent Pre-Decision Tools. Do not submit"
+        " them in the same tool-call list as a Turn-Ending Action; inspect their result"
+        " first. The write-through tools `update_note` and `append_note` may accompany"
+        " at most one Turn-Ending Action when their content is based entirely on"
+        " evidence already available before that action. Never write an action's"
+        " expected outcome as if it had already been observed."
+    )
+
+
+def _tool_protocol(available: frozenset[str]) -> str:
+    helper = render_tool_enum(_PRE_DECISION_HELPER_TOOLS, available)
+    adb = render_tool_enum(_PRE_DECISION_ADB_TOOLS, available)
+    memory = render_tool_enum(_PRE_DECISION_MEMORY_TOOLS, available)
+    return (
+        "1. **Result-Dependent Pre-Decision Tools**:\n"
+        f"   - *What they are*: Helper/Subagent tools ({helper}), ADB/task tools"
+        f" ({adb}), and memory tools whose result must be inspected ({memory}).\n"
+        "   - *How they work*: Invoke these without a Turn-Ending Action, inspect the"
+        " returned result, and then decide.\n"
+        "2. **Write-Through Memory Tools**:\n"
+        "   - `update_note` and `append_note` may run alongside at most one Turn-Ending"
+        " Action only when recording facts already observed in the current context. If"
+        " the note content depends on the action's result, wait for the next"
+        " observation before writing it.\n"
+        "3. **Turn-Ending Actions**:"
+    )
 
 _LEGACY_CHECKER_REJECTION_TRIGGER = """   - **Validation/Checker Rejection**: The verification agent (Checker) rejected your subgoal completion (i.e., you are in troubleshooter mode and this is a retry)."""
 
@@ -70,15 +188,28 @@ _LARGE_LIST_STRATEGY = """- **Large List & Long Text Exploration Strategy (Zero-
   4. **Single-Pass Trust & Anti-Oscillation (No Over-Verification)**: Treat recorded notes as verified ground truth. Once a segment is traversed with confirmed anchor continuity and logged, consider it permanently resolved. Do NOT scroll back-and-forth or perform redundant re-scans for "double-checking", even if older execution history has been pruned. Resume from the last recorded anchor and direction. Only the single bounded recovery above, or a refreshed/mutated list, permits limited re-verification; otherwise continue the single pass over new content."""
 
 
-def apply_operator_prompt_contract(prompt_template: str) -> str:
-    """Align prompt-level tool and recovery rules with Operator runtime semantics."""
+def apply_operator_prompt_contract(
+    prompt_template: str,
+    available_tools: frozenset[str] | None = None,
+) -> str:
+    """Align prompt-level tool and recovery rules with Operator runtime semantics.
+
+    Args:
+        prompt_template: One of the raw operator.json templates.
+        available_tools: Tools that actually exist this run. ``None`` renders with the
+            full historical tool set, producing byte-identical output to the
+            pre-assembly contract. Unavailable tools disappear from every enumeration
+            slot, and instruction segments teaching them are removed wholesale.
+    """
+    available = frozenset(resolve_available(available_tools, OPERATOR_PROMPT_TOOLSET))
+
     prompt_template = prompt_template.replace(
         _LEGACY_TOOL_CALLING_RULE,
-        _TOOL_CALLING_RULE,
+        _tool_calling_rule(available),
     )
     prompt_template = prompt_template.replace(
         _LEGACY_TOOL_PROTOCOL,
-        _TOOL_PROTOCOL,
+        _tool_protocol(available),
     )
     prompt_template = prompt_template.replace(
         _LEGACY_CHECKER_REJECTION_TRIGGER,
@@ -92,6 +223,44 @@ def apply_operator_prompt_contract(prompt_template: str) -> str:
         _LEGACY_LARGE_LIST_STRATEGY,
         _LARGE_LIST_STRATEGY,
     )
+
+    # Device-action enumeration slots (identical in both templates).
+    prompt_template = prompt_template.replace(
+        _PHYSICAL_ACTIONS_SLOT,
+        "Physical device actions ("
+        + render_tool_enum(_PHYSICAL_ACTIONS_ORDER, available)
+        + ")",
+    )
+    prompt_template = prompt_template.replace(
+        _TURN_ENDING_SLOT,
+        "Turn-Ending Action ("
+        + render_tool_enum(_TURN_ENDING_ORDER, available, final_sep="or")
+        + ")",
+    )
+
+    # Instruction segments that teach a single tool.
+    prompt_template = prompt_template.replace(
+        _WAIT_FOR_DELAY_TRANSITIONS_SEGMENT,
+        gate_segment(_WAIT_FOR_DELAY_TRANSITIONS_SEGMENT, available, "wait_for_delay"),
+    )
+    prompt_template = prompt_template.replace(
+        _WAIT_FOR_DELAY_INTERVAL_PARENTHETICAL,
+        gate_segment(
+            _WAIT_FOR_DELAY_INTERVAL_PARENTHETICAL, available, "wait_for_delay"
+        ),
+    )
+    prompt_template = prompt_template.replace(
+        _VIDEO_ANALYZER_TRANSIENT_SEGMENT,
+        gate_segment(_VIDEO_ANALYZER_TRANSIENT_SEGMENT, available, "video_analyzer"),
+    )
+    prompt_template = prompt_template.replace(
+        _VIDEO_ANALYZER_SNAPSHOT_SENTENCE,
+        gate_segment(_VIDEO_ANALYZER_SNAPSHOT_SENTENCE, available, "video_analyzer"),
+    )
+    prompt_template = prompt_template.replace(
+        _SWIPE_PRECISION_SEGMENT,
+        gate_segment(_SWIPE_PRECISION_SEGMENT, available, "swipe"),
+    )
     return prompt_template
 
 
@@ -143,7 +312,31 @@ class TemplatePromptComponent(PromptComponent):
                 "Failed to format prompt, template not found in operator prompts config."
             )
 
-        prompt_template = apply_operator_prompt_contract(prompt_template)
+        # video_analyzer is bound conditionally (graph.py gates it on
+        # video_recording_tools_enabled); the prompt must not advertise it when the
+        # tool is not actually available this run.
+        available = set(OPERATOR_PROMPT_TOOLSET)
+        setup = getattr(ctx, "execution_setup", None)
+        if not (setup and getattr(setup, "video_recording_tools_enabled", False)):
+            available.discard("video_analyzer")
+
+        # Device actions the installed actuator backend does not implement disappear
+        # from the prompt in lockstep with their tool declarations.
+        actuator = getattr(ctx, "actuator", None)
+        if actuator is not None and callable(getattr(actuator, "capabilities", None)):
+            try:
+                from artemis.mcp.action_manifest import (
+                    DEVICE_ACTIONS,
+                    available_device_actions,
+                )
+
+                available -= DEVICE_ACTIONS - available_device_actions(actuator)
+            except Exception as e:
+                logger.warning(f"Failed to assemble prompt against actuator: {e}")
+
+        prompt_template = apply_operator_prompt_contract(
+            prompt_template, available_tools=frozenset(available)
+        )
 
         plan_and_history = kwargs.get("plan_and_history", "No plan or history yet.")
 

artemis/agents/prompt_assembly.py

@@ -0,0 +1,79 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Helpers for assembling tool references into otherwise-static prompts.
+
+Prompts stay hand-written text; only the spots that mention tools are assembled:
+
+* **Enumeration slots** -- lists like ``(`click`, `swipe`, ... , or `wait_for_delay`)``
+  are re-rendered from the actually-available tool set, so an absent tool never
+  appears. With the full tool set the rendering reproduces the original wording
+  byte-for-byte (ordering, backticks, Oxford ``or``/``and``), which is what the
+  regression tests pin.
+* **Instruction segments** -- self-contained blocks that teach one tool (e.g. the
+  ``manage_app`` app-launching rule) are included only while that tool exists.
+
+An unavailable tool therefore leaves no trace in the prompt at all -- the executable
+definition of "an unimplemented tool must cost the model nothing".
+"""
+
+from collections.abc import Iterable, Sequence, Set
+
+__all__ = ["gate_segment", "render_tool_enum", "resolve_available"]
+
+
+def render_tool_enum(
+    tools: Sequence[str],
+    available: Set[str],
+    final_sep: str | None = None,
+) -> str:
+    """Renders an ordered, backticked tool enumeration limited to available tools.
+
+    Args:
+        tools: Tool names in the exact order the prompt historically used.
+        available: Tools that currently exist.
+        final_sep: ``"or"``/``"and"`` to join the last item Oxford-style
+            (``"`a`, `b`, or `c`"``); ``None`` for a plain comma list.
+
+    Returns:
+        The rendered enumeration, or ``""`` when none of the tools are available.
+    """
+    ticked = [f"`{name}`" for name in tools if name in available]
+    if not ticked:
+        return ""
+    if len(ticked) == 1:
+        return ticked[0]
+    if final_sep is None:
+        return ", ".join(ticked)
+    if len(ticked) == 2:
+        return f"{ticked[0]} {final_sep} {ticked[1]}"
+    return ", ".join(ticked[:-1]) + f", {final_sep} " + ticked[-1]
+
+
+def gate_segment(segment: str, available: Set[str], *tools: str) -> str:
+    """Returns ``segment`` when every tool it teaches is available, else ``""``."""
+    if all(name in available for name in tools):
+        return segment
+    return ""
+
+
+def resolve_available(available: Iterable[str] | None, full_set: Set[str]) -> Set[str]:
+    """Normalizes an optional availability argument.
+
+    ``None`` means "everything" -- callers that have no actuator wired yet keep
+    today's output unchanged. Passing an explicit set opts into assembly.
+    """
+    if available is None:
+        return full_set
+    return frozenset(available)

artemis/agents/validator/failure_analyzer.py

@@ -36,7 +36,7 @@ from langchain_core.messages import (
 from artemis.agents.validator.tool_declarations import (
     ASK_EXPLORER_TOOL,
     CLICK_SEQUENCE_TOOL,
-    MobileActionExecutor,
+    MobileActionExecutor,  # Legacy shims below; the loop itself uses McpActionExecutor.
     ToolDeclaration,
     VALIDATOR_TOOLS_DECLARATION,
     capture_screenshot_and_parse_ui,
@@ -46,6 +46,7 @@ from artemis.context import ArtemisContext
 from artemis.controllers.unified_controller import UnifiedMobileController
 from artemis.data_engine.trace import trace
 from artemis.graph.state import State
+from artemis.mcp.action_executor import McpActionExecutor
 from artemis.services.llm import get_llm
 from artemis.utils.logger import get_logger
 from artemis.utils.notes import get_note_file_path
@@ -230,6 +231,16 @@ class FailureAnalysisStrategy:
     def get_tools(self) -> list:
         return VALIDATOR_TOOLS_DECLARATION
 
+    def required_tools(self) -> frozenset[str]:
+        """Tools this strategy's prompt depends on structurally.
+
+        A strategy whose prompt is built around a tool (rather than merely listing it)
+        must declare it here; strategy selection falls back to the base strategy when
+        the current backend does not provide every required tool, so the dependent
+        prompt is never rendered against a backend that cannot satisfy it.
+        """
+        return frozenset()
+
     def get_user_message_suffix(self, pre_screenshot: bool, post_screenshot: bool) -> str:
         suffix = (
             "Your objective is:\n"
@@ -268,6 +279,11 @@ class TargetDisappearedStrategy(FailureAnalysisStrategy):
         tools.append(ASK_EXPLORER_TOOL)
         return tools
 
+    def required_tools(self) -> frozenset[str]:
+        # The whole prompt is built around atomic chained execution to defeat turn
+        # latency, which *is* click_sequence.
+        return frozenset({"click_sequence"})
+
     def get_user_message_suffix(self, pre_screenshot: bool, post_screenshot: bool) -> str:
         return ""
 
@@ -284,6 +300,9 @@ class PixelTargetDisappearedStrategy(FailureAnalysisStrategy):
         tools.append(ASK_EXPLORER_TOOL)
         return tools
 
+    def required_tools(self) -> frozenset[str]:
+        return frozenset({"click_sequence"})
+
     def get_user_message_suffix(self, pre_screenshot: bool, post_screenshot: bool) -> str:
         return ""
 
@@ -295,15 +314,33 @@ class FailureAnalyzer:
         self.ctx = ctx
         self.max_iterations = 15
 
-    def _select_strategy(self, error_category: ValidationErrorCategory) -> FailureAnalysisStrategy:
+    def _select_strategy(
+        self,
+        error_category: ValidationErrorCategory,
+        available_tools: frozenset[str] | None = None,
+    ) -> FailureAnalysisStrategy:
         if error_category == ValidationErrorCategory.PIXEL_TARGET_DISAPPEARED:
             logger.info("Routing failure analysis to specialized PixelTargetDisappearedStrategy.")
-            return PixelTargetDisappearedStrategy()
-        if error_category == ValidationErrorCategory.TARGET_DISAPPEARED:
+            strategy: FailureAnalysisStrategy = PixelTargetDisappearedStrategy()
+        elif error_category == ValidationErrorCategory.TARGET_DISAPPEARED:
             logger.info("Routing failure analysis to specialized TargetDisappearedStrategy.")
-            return TargetDisappearedStrategy()
-        logger.info("Routing failure analysis to DefaultAnalysisStrategy.")
-        return FailureAnalysisStrategy()
+            strategy = TargetDisappearedStrategy()
+        else:
+            logger.info("Routing failure analysis to DefaultAnalysisStrategy.")
+            strategy = FailureAnalysisStrategy()
+
+        # Capability gating: a strategy and its prompt are one unit. If the backend
+        # cannot satisfy the tools the prompt is built around, fall back to the base
+        # strategy so the dependent prompt is never rendered. `None` = no gating.
+        if available_tools is not None:
+            missing = strategy.required_tools() - available_tools
+            if missing:
+                logger.warning(
+                    f"Strategy {type(strategy).__name__} requires unavailable tool(s)"
+                    f" {sorted(missing)}; falling back to base FailureAnalysisStrategy."
+                )
+                return FailureAnalysisStrategy()
+        return strategy
 
     def _get_active_subgoal_hash(self) -> str:
         if not self.ctx.data_engine:
@@ -363,7 +400,12 @@ class FailureAnalyzer:
         if not pre_screenshot:
             raise ValueError("Failure analysis requires valid screenshots.")
 
-        strategy = self._select_strategy(error_category)
+        controller = UnifiedMobileController(self.ctx)
+        executor = McpActionExecutor(self.ctx, controller)
+
+        strategy = self._select_strategy(
+            error_category, available_tools=frozenset(executor.action_tool_names)
+        )
         prompt_template_name = strategy.get_prompt_template_name()
         tools_declaration = strategy.get_tools()
 
@@ -372,9 +414,6 @@ class FailureAnalyzer:
         except Exception:
             llm = get_llm(self.ctx, name="validator")
 
-        controller = UnifiedMobileController(self.ctx)
-        executor = MobileActionExecutor(self.ctx, controller)
-
         # Pre-Action and Post-Action XML formatting
         pre_xml_list_str = "Not available."
         if hasattr(state, "latest_ui_hierarchy") and state.latest_ui_hierarchy:

artemis/agents/validator/tool_declarations.py

@@ -15,35 +15,31 @@
 """Universal Tool Declarations, Execution Results, and Dispatcher for Artemis."""
 
 import ast
-import asyncio
 import base64
 import hashlib
-import inspect
 import json
 from pathlib import Path
-import time
 from typing import Any, Literal
 
 from google.genai import types as genai_types
 from langchain_core.messages import ToolMessage
 from pydantic import BaseModel, Field
 
-from artemis.config import get_temp_dir, resolve_explorer_version
+from artemis.config import resolve_explorer_version
 from artemis.context import ArtemisContext
 from artemis.controllers.unified_controller import UnifiedMobileController
 from artemis.core.tool_declaration import ToolDeclaration
 from artemis.data_engine.trace import trace
+from artemis.mcp.action_types import ActionCode
+from artemis.mcp.actuators.adb import AdbActuator
+from artemis.mcp.observation import observe
 from artemis.tools.explorer_tool import _run_explorer_logic
 from artemis.graph.state import State
-from artemis.tools.mobile.launch_app import find_package
-from artemis.utils.app_launch_utils import launch_app_with_retries
 from artemis.utils.coordinates import (
     compute_smart_swipe_coordinates,
     parse_swipe_parameters,
 )
 from artemis.utils.logger import get_logger
-from artemis.utils.ocr_xml_fusion import fuse_ocr_with_xml
-from artemis.utils.visualization import format_minimal_list_with_elements
 from artemis.utils.notes import (
     LIST_NOTES_DOCSTRING,
     READ_NOTE_ARG_KEY_DESC,
@@ -186,65 +182,22 @@ async def capture_screenshot_and_parse_ui(
     controller: UnifiedMobileController,
     skip_settling: bool = False,
 ) -> tuple[str | None, bytes | None, str | None]:
-    """Captures screenshot and parses fused XML tree after optional screen settling delay."""
-    try:
-        if skip_settling:
-            logger.info("Retrieving screen data directly (skip settling)...")
-            device_data = await controller.get_screen_data()
-            latest_screenshot_b64 = device_data.base64
-        else:
-            logger.info("Delaying 0.4s before capturing screen state...")
-            await asyncio.sleep(0.4)
-            device_data = await controller.get_screen_data()
-            latest_screenshot_b64 = device_data.base64
+    """Captures screenshot and parses fused XML tree after optional screen settling delay.
 
-        latest_screenshot_bytes = base64.b64decode(latest_screenshot_b64)
-    except Exception as e:
-        logger.error(f"Failed to capture screen state: {e}")
+    Thin adapter over :func:`artemis.mcp.observation.observe` that adds the LangGraph
+    ``State`` write-back (indexed points/elements) the agents rely on.
+    """
+    obs, screenshot_bytes = await observe(
+        ctx, controller, settle_ms=0 if skip_settling else 400
+    )
+    if not obs.ok:
         return None, None, None
 
-    try:
-        xml_hierarchy = device_data.elements
-        width = device_data.width or 1080
-        height = device_data.height or 2400
-        if ctx.device:
-            ctx.device.device_width = width
-            ctx.device.device_height = height
+    if obs.hierarchy_ok:
+        state.indexed_points = [el["center"] for el in obs.elements]
+        state.indexed_elements = obs.elements
 
-        ocr_results = []
-
-        fused_xml = fuse_ocr_with_xml(xml_hierarchy, ocr_results)
-
-        minimal_list_str, elements, _ = format_minimal_list_with_elements(fused_xml, width, height)
-
-        state.indexed_points = [el["center"] for el in elements]
-        state.indexed_elements = elements
-    except Exception as e:
-        logger.error(f"Failed to fetch or fuse UI hierarchy: {e}")
-        minimal_list_str = "Not available due to hierarchy error."
-
-    screenshot_path = None
-    if ctx.data_engine:
-        try:
-            image_name = ctx.data_engine.get_or_create_image(
-                latest_screenshot_bytes,
-                ui_tree=xml_hierarchy,
-                ocr_result=ocr_results,
-            )
-            screenshot_path = str(ctx.data_engine.get_image_path(image_name))
-        except Exception as e:
-            logger.error(f"Failed to save image in DataEngine: {e}")
-
-    if not screenshot_path:
-        try:
-            temp_dir = get_temp_dir("screenshots")
-            temp_file = temp_dir / f"screenshot_{int(time.time())}.jpg"
-            temp_file.write_bytes(latest_screenshot_bytes)
-            screenshot_path = str(temp_file)
-        except Exception as e:
-            logger.error(f"Failed to save fallback screenshot: {e}")
-
-    return screenshot_path, latest_screenshot_bytes, minimal_list_str
+    return obs.screenshot_path, screenshot_bytes, obs.elements_text
 
 
 def normalize_coordinate_target(target: Any) -> int | list[int] | Any:
@@ -313,11 +266,23 @@ def serialize_mobile_action_result(result: Any) -> dict[str, Any]:
 
 
 class MobileActionExecutor:
-    """Encapsulates device action execution, observation capture, and result reporting."""
+    """Adapts LLM tool calls onto an actuator backend and captures observations.
 
-    def __init__(self, ctx: ArtemisContext, controller: UnifiedMobileController | None = None):
+    Device-call bodies live in the actuator (``artemis/mcp/actuators/``); this class
+    keeps the agent-side responsibilities: argument normalization, index resolution
+    against LangGraph ``State``, act-then-observe screenshot capture, tracing, and the
+    legacy 4-tuple result contract.
+    """
+
+    def __init__(
+        self,
+        ctx: ArtemisContext,
+        controller: UnifiedMobileController | None = None,
+        actuator: "AdbActuator | None" = None,
+    ):
         self.ctx = ctx
-        self.controller = controller or UnifiedMobileController(ctx)
+        self.actuator = actuator or AdbActuator(ctx, controller)
+        self.controller = self.actuator.controller
 
     @trace(type="action", name="click", serializer=serialize_mobile_action_result)
     async def exec_click(
@@ -327,27 +292,16 @@ class MobileActionExecutor:
         times: int = 1,
         delay_ms: int = 100,
     ) -> tuple[str, bytes | None, str | None, str | None]:
-        width = getattr(self.ctx.device, "device_width", 1080)
-        height = getattr(self.ctx.device, "device_height", 2400)
         try:
             target = normalize_coordinate_target(target)
             if not isinstance(target, (list, tuple)) or len(target) != 2:
                 raise ValueError(f"Invalid target format: {target}")
             nx, ny = target
-            x = int(max(0, min(width - 1, int(nx) * width / 1000)))
-            y = int(max(0, min(height - 1, int(ny) * height / 1000)))
-
-            result = await self.controller.tap_at(x, y, times=times, delay_ms=delay_ms)
-            err = getattr(result, "error", None) if result else None
-            success = err is None
-            outcome = (
-                f"Clicked at [{nx}, {ny}] (normalized) successfully."
-                if success
-                else f"Error executing click: {err}"
-            )
+            res = await self.actuator.click(int(nx), int(ny), times=times, delay_ms=delay_ms)
+            outcome = res.message
 
             img_bytes, shot_path, xml_list = None, None, None
-            if success:
+            if res.ok:
                 shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                     self.ctx, state, self.controller
                 )
@@ -385,15 +339,20 @@ class MobileActionExecutor:
                     None,
                 )
 
-            outcomes = []
-            for i, raw_target in enumerate(sequence):
+            # Resolve each entry to normalized coordinates: integer element indices go
+            # through state.indexed_points (pixel centers -> normalized), coordinate
+            # pairs are already normalized.
+            norm_points: list[tuple[int, int]] = []
+            for raw_target in sequence:
                 target = normalize_coordinate_target(raw_target)
                 if isinstance(target, int):
                     idx = target
                     points = getattr(state, "indexed_points", []) or []
                     if 1 <= idx <= len(points):
                         pt = points[idx - 1]
-                        x, y = int(pt[0]), int(pt[1])
+                        px, py = int(pt[0]), int(pt[1])
+                        nx = int(max(0, min(1000, round(px * 1000 / max(1, width)))))
+                        ny = int(max(0, min(1000, round(py * 1000 / max(1, height)))))
                     else:
                         return (
                             (
@@ -405,9 +364,7 @@ class MobileActionExecutor:
                             None,
                         )
                 elif isinstance(target, (list, tuple)) and len(target) == 2:
-                    nx, ny = target
-                    x = int(max(0, min(width - 1, int(nx) * width / 1000)))
-                    y = int(max(0, min(height - 1, int(ny) * height / 1000)))
+                    nx, ny = int(target[0]), int(target[1])
                 else:
                     return (
                         f"Error during click sequence: Invalid target format: {raw_target}",
@@ -415,25 +372,16 @@ class MobileActionExecutor:
                         None,
                         None,
                     )
+                norm_points.append((nx, ny))
 
-                result = await self.controller.tap_at(x, y)
-                err = getattr(result, "error", None) if result else None
-                if err:
-                    return (
-                        f"Error executing click at step {i + 1}: {err}",
-                        None,
-                        None,
-                        None,
-                    )
-                outcomes.append(f"Tapped at [{x}, {y}]")
-                if i < len(sequence) - 1:
-                    await asyncio.sleep(max(0, delay_ms) / 1000.0)
+            res = await self.actuator.click_sequence(norm_points, delay_ms=delay_ms)
+            if not res.ok:
+                return res.message, None, None, None
 
-            outcome_str = f"Sequence clicked successfully: {'; '.join(outcomes)}"
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )
-            return outcome_str, img_bytes, shot_path, xml_list
+            return res.message, img_bytes, shot_path, xml_list
         except Exception as e:
             return f"Error executing click sequence: {e}", None, None, None
 
@@ -445,8 +393,6 @@ class MobileActionExecutor:
         duration_ms: int = 1000,
         duration: int | None = None,
     ) -> tuple[str, bytes | None, str | None, str | None]:
-        width = getattr(self.ctx.device, "device_width", 1080)
-        height = getattr(self.ctx.device, "device_height", 2400)
         if duration is not None:
             duration_ms = duration
         try:
@@ -454,22 +400,11 @@ class MobileActionExecutor:
             if not isinstance(target, (list, tuple)) or len(target) != 2:
                 raise ValueError(f"Invalid target format: {target}")
             nx, ny = target
-            x = int(max(0, min(width - 1, int(nx) * width / 1000)))
-            y = int(max(0, min(height - 1, int(ny) * height / 1000)))
-
-            result = await self.controller.tap_at(
-                x, y, long_press=True, long_press_duration=duration_ms
-            )
-            err = getattr(result, "error", None) if result else None
-            success = err is None
-            outcome = (
-                f"Long pressed at [{nx}, {ny}] (normalized) for {duration_ms}ms successfully."
-                if success
-                else f"Error executing long press: {err}"
-            )
+            res = await self.actuator.long_press(int(nx), int(ny), duration_ms=duration_ms)
+            outcome = res.message
 
             img_bytes, shot_path, xml_list = None, None, None
-            if success:
+            if res.ok:
                 shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                     self.ctx, state, self.controller
                 )
@@ -487,24 +422,16 @@ class MobileActionExecutor:
         state: State,
         clear_exist: bool = True,
     ) -> tuple[str, bytes | None, str | None, str | None]:
-        width = getattr(self.ctx.device, "device_width", 1080)
-        height = getattr(self.ctx.device, "device_height", 2400)
         try:
+            norm_target: tuple[int, int] | None = None
             if target:
                 target = normalize_coordinate_target(target)
                 if not isinstance(target, (list, tuple)) or len(target) != 2:
                     raise ValueError(f"Invalid target format: {target}")
-                nx, ny = target
-                x = int(max(0, min(width - 1, int(nx) * width / 1000)))
-                y = int(max(0, min(height - 1, int(ny) * height / 1000)))
+                norm_target = (int(target[0]), int(target[1]))
 
-                await self.controller.tap_at(x, y)
-            if clear_exist and hasattr(self.controller, "erase_text"):
-                await self.controller.erase_text()
-            if hasattr(self.controller, "type_text"):
-                await self.controller.type_text(text)
-
-            outcome = f"Executed typing '{text}'."
+            res = await self.actuator.input_text(text, norm_target, clear_exist=clear_exist)
+            outcome = res.message
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )
@@ -540,6 +467,8 @@ class MobileActionExecutor:
         try:
             if kind == "direction":
                 dir_name = target
+                # Smart-swipe resolution needs State (indexed elements + ui tree), so
+                # it stays client-side; the actuator only receives the two points.
                 x1, y1, x2, y2, smart_dur = compute_smart_swipe_coordinates(
                     direction=target,
                     target=swipe_input.get("target"),
@@ -550,19 +479,21 @@ class MobileActionExecutor:
                     duration=final_duration,
                 )
                 final_duration = smart_dur
-                err = await self.controller.swipe_coords(x1, y1, x2, y2, final_duration)
-                if err:
-                    return f"Error swiping {dir_name}: {err}", None, None, None
+                nx1 = int(max(0, min(1000, round(x1 * 1000 / max(1, width)))))
+                ny1 = int(max(0, min(1000, round(y1 * 1000 / max(1, height)))))
+                nx2 = int(max(0, min(1000, round(x2 * 1000 / max(1, width)))))
+                ny2 = int(max(0, min(1000, round(y2 * 1000 / max(1, height)))))
+                res = await self.actuator.swipe((nx1, ny1), (nx2, ny2), final_duration)
+                if not res.ok:
+                    return f"Error swiping {dir_name}: {res.detail}", None, None, None
                 outcome = f"Swipe completed successfully. Swiped {dir_name}."
             elif kind == "coords":
                 x1, y1, x2, y2 = target
-                px1 = int(max(0, min(width - 1, int(x1) * width / 1000)))
-                py1 = int(max(0, min(height - 1, int(y1) * height / 1000)))
-                px2 = int(max(0, min(width - 1, int(x2) * width / 1000)))
-                py2 = int(max(0, min(height - 1, int(y2) * height / 1000)))
-                err = await self.controller.swipe_coords(px1, py1, px2, py2, final_duration)
-                if err:
-                    return f"Error dragging: {err}", None, None, None
+                res = await self.actuator.swipe(
+                    (int(x1), int(y1)), (int(x2), int(y2)), final_duration
+                )
+                if not res.ok:
+                    return f"Error dragging: {res.detail}", None, None, None
                 outcome = f"Swipe completed successfully. Swiped from [{x1}, {y1}] to [{x2}, {y2}]."
             else:
                 return (
@@ -589,24 +520,11 @@ class MobileActionExecutor:
         state: State,
     ) -> tuple[str, bytes | None, str | None, str | None]:
         try:
-            valid_keys = {"home", "back", "enter", "delete", "tab", "search", "menu", "app_switch"}
-            key_str = str(key).lower()
-            if key_str not in valid_keys:
-                return f"Error executing key press '{key}'.", None, None, None
+            res = await self.actuator.press_key(key)
+            if not res.ok:
+                return res.message, None, None, None
 
-            if key_str == "back" and hasattr(self.controller, "go_back"):
-                await self.controller.go_back()
-            elif key_str == "home" and hasattr(self.controller, "go_home"):
-                await self.controller.go_home()
-            elif key_str == "enter" and hasattr(self.controller, "press_enter"):
-                await self.controller.press_enter()
-            elif hasattr(self.controller, "press_key"):
-                res = await self.controller.press_key(key)
-                err = getattr(res, "error", None) if res else None
-                if err:
-                    return f"Error executing key press '{key}': {err}", None, None, None
-
-            outcome = f"Executed key press '{key}'."
+            outcome = res.message
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )
@@ -624,35 +542,13 @@ class MobileActionExecutor:
         state: State,
     ) -> tuple[str, bytes | None, str | None, str | None]:
         try:
-            res = find_package(self.ctx, app_name, use_fallback=False)
-            pkg = await res if inspect.iscoroutine(res) else res
-            if not pkg:
-                return f"Error finding package for app: {app_name}", None, None, None
-            target_pkg = pkg
-
-            if action.lower() == "launch":
-                res_launch = launch_app_with_retries(self.ctx, target_pkg)
-                if inspect.iscoroutine(res_launch):
-                    res_launch = await res_launch
-                if isinstance(res_launch, tuple):
-                    success, error_msg = res_launch
-                else:
-                    success, error_msg = bool(res_launch), ""
-
-                outcome = (
-                    f"Launched app '{app_name}' ({target_pkg}) successfully."
-                    if success
-                    else f"Failed to launch app '{app_name}': {error_msg}"
-                )
-            elif action.lower() == "stop":
-                if hasattr(self.controller, "terminate_app"):
-                    res_term = self.controller.terminate_app(target_pkg)
-                    if inspect.iscoroutine(res_term):
-                        await res_term
-                outcome = f"Terminated app '{app_name}' successfully."
-            else:
-                return f"Invalid manage_app action: {action}", None, None, None
+            res = await self.actuator.manage_app(action, app_name)
+            # Argument-level failures return without an observation, exactly as the
+            # historical early returns did; a failed launch still captures the screen.
+            if res.code in (ActionCode.PACKAGE_NOT_FOUND, ActionCode.INVALID_ARGS):
+                return res.message, None, None, None
 
+            outcome = res.message
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )
@@ -669,9 +565,8 @@ class MobileActionExecutor:
         state: State,
     ) -> tuple[str, bytes | None, str | None, str | None]:
         try:
-            delay_s = max(0.0, float(time_in_ms) / 1000.0)
-            await asyncio.sleep(delay_s)
-            outcome = f"Waited for {time_in_ms}ms successfully."
+            res = await self.actuator.wait_for_delay(time_in_ms)
+            outcome = res.message
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )
@@ -690,27 +585,9 @@ class MobileActionExecutor:
         state: State,
     ) -> tuple[str, bytes | None, str | None, str | None]:
         try:
-            timeout_s = (timeout_ms or 5000) / 1000.0
-            start = time.time()
-            found = False
-            target_state = (wait_state or "appear").lower()
-
-            while time.time() - start < timeout_s:
-                tree = await self.controller.get_ui_elements()
-                text_present = text.lower() in (tree or "").lower()
-                if target_state == "appear" and text_present:
-                    found = True
-                    break
-                elif target_state == "disappear" and not text_present:
-                    found = True
-                    break
-                await asyncio.sleep(0.5)
-
-            outcome = (
-                f"Successfully waited for text '{text}' to {target_state}."
-                if found
-                else f"Timed out waiting for text '{text}' to {target_state}."
-            )
+            res = await self.actuator.wait_for_text(text, wait_state, timeout_ms)
+            outcome = res.message
+            # A timeout still captures the screen, as the original loop did.
             shot_path, img_bytes, xml_list = await capture_screenshot_and_parse_ui(
                 self.ctx, state, self.controller
             )

artemis/agents/validator/validator.py

@@ -17,39 +17,31 @@ import base64
 import difflib
 import json
 import math
-import os
 from pathlib import Path
-import psutil
 import re
-import sys
 import time
 import traceback
 import uuid
 from uuid import UUID
 
-from adbutils import AdbClient
-from mcp import ClientSession, StdioServerParameters
-from mcp.client.stdio import stdio_client
-
 from langchain_core.messages import HumanMessage, SystemMessage
 from artemis.agents.validator.failure_analyzer import (
     FailureAnalyzer,
     ValidationErrorCategory,
 )
-from artemis.clients.ui_automator_client import UIAutomatorClient
 from artemis.constants import (
     VALIDATOR_POLL_INTERVAL,
     VALIDATOR_POLL_TIMEOUT,
     VALIDATOR_UI_HIERARCHY_TIMEOUT,
 )
-from artemis.context import ArtemisContext, DeviceContext, DevicePlatform
+from artemis.context import ArtemisContext
 from artemis.controllers.unified_controller import UnifiedMobileController
 from artemis.data_engine.trace import CURRENT_TRACE_ID, trace
 from artemis.graph.state import State
-from artemis.platform import platform
+from artemis.mcp.action_names import to_canonical_call
+from artemis.mcp.action_session import ActionSession, get_action_session
 from artemis.services.llm import get_llm
-from artemis.tools.mobile.launch_app import find_package
-from artemis.utils import app_launch_utils, image_diff, visualization
+from artemis.utils import image_diff, visualization
 from artemis.utils.decorators import wrap_with_callbacks
 from artemis.utils.logger import get_logger
 
@@ -85,151 +77,14 @@ class ValidatorNode:
     def __init__(self, ctx: ArtemisContext):
         self.ctx = ctx
 
-    def _kill_mcp_server_instantly(self):
-        """Instantly terminate MCP ADB server child processes."""
+    async def _get_mcp_session(self) -> ActionSession:
+        """Returns the in-process unified action session (created lazily on ctx).
 
-        try:
-            current_process = psutil.Process()
-            children = current_process.children(recursive=True)
-            for child in children:
-                try:
-                    cmdline = child.cmdline()
-                    if any("adb_server.py" in part for part in cmdline):
-                        logger.warning(f"Instantly killing MCP Server child process: {child.pid}")
-                        child.kill()
-                except psutil.NoSuchProcess:
-                    pass
-        except Exception as e:
-            logger.error(f"Failed to instantly kill MCP server child processes: {e}")
-
-    async def _close_failed_mcp_session(
-        self,
-        *,
-        session,
-        session_entered: bool,
-        client_ctx,
-        client_entered: bool,
-    ) -> bool:
-        """Exit partially-entered MCP contexts in reverse order.
-
-        The MCP stdio transport owns an AnyIO task group and cancellation
-        scope. Dropping an entered transport without calling ``__aexit__``
-        leaves that scope attached to the validator task and can cancel an
-        unrelated action later in the same node.
-
-        Returns ``True`` when every entered context closed cleanly.
+        The previous stdio-subprocess spawn -- and its local-controller fallback,
+        which on Windows was the *only* path that ever ran -- is gone: the server now
+        lives in-process, so there is no spawn to fail and exactly one execution path.
         """
-        self.ctx.mcp_session = None
-        self.ctx.mcp_client_ctx = None
-        cleanup_succeeded = True
-
-        for manager, entered, label in (
-            (session, session_entered, "MCP session"),
-            (client_ctx, client_entered, "MCP stdio transport"),
-        ):
-            if not entered or manager is None:
-                continue
-            try:
-                await manager.__aexit__(None, None, None)
-            except asyncio.CancelledError:
-                cleanup_succeeded = False
-                logger.warning(f"{label} cleanup was cancelled.")
-            except Exception as cleanup_error:
-                cleanup_succeeded = False
-                logger.warning(f"Failed to close {label}: {cleanup_error}")
-
-        return cleanup_succeeded
-
-    async def _get_mcp_session(self):
-        if getattr(self.ctx, "mcp_session", None) is not None:
-            return self.ctx.mcp_session
-
-        root_dir = Path(__file__).parent.parent.parent
-        venv_python = root_dir / ".venv" / "bin" / "python3"
-        python_exe = str(venv_python) if venv_python.exists() else sys.executable
-
-        server_env = os.environ.copy()
-        # The parent Artemis process already owns the device-awake policy.
-        # Starting it again in this short-lived child can block the MCP
-        # handshake on cross-process ADB/lease cleanup.
-        server_env["ARTEMIS_KEEP_DEVICE_AWAKE"] = "false"
-        server_params = StdioServerParameters(
-            command=python_exe,
-            args=[str(root_dir / "mcp" / "adb_server.py")],
-            env=server_env,
-        )
-
-        logger.info("Starting persistent MCP server session...")
-        client_ctx = stdio_client(server_params)
-        session = None
-        client_entered = False
-        session_entered = False
-        self.ctx.mcp_client_ctx = client_ctx
-        try:
-            read, write = await client_ctx.__aenter__()
-            client_entered = True
-            session = ClientSession(read, write)
-            self.ctx.mcp_session = session
-            await session.__aenter__()
-            session_entered = True
-            # Handshake timeout protection
-            await asyncio.wait_for(session.initialize(), timeout=15.0)
-            return session
-        except asyncio.CancelledError:
-            await self._close_failed_mcp_session(
-                session=session,
-                session_entered=session_entered,
-                client_ctx=client_ctx,
-                client_entered=client_entered,
-            )
-            raise
-        except Exception as e:
-            err_stack = traceback.format_exc()
-            logger.critical(
-                "CRITICAL: Failed to initialize MCP server session:"
-                f" {e}\n{err_stack}. Cleaning up child processes."
-            )
-            cleanup_succeeded = await self._close_failed_mcp_session(
-                session=session,
-                session_entered=session_entered,
-                client_ctx=client_ctx,
-                client_entered=client_entered,
-            )
-            if not cleanup_succeeded:
-                self._kill_mcp_server_instantly()
-
-            logger.warning(
-                "Falling back to robust local in-process execution bypassing MCP protocol."
-            )
-
-            try:
-                adb = AdbClient(host="localhost", port=5037)
-                devices = adb.device_list()
-                if devices:
-                    device_id = devices[0].serial
-                    ui_client = UIAutomatorClient(device_id=device_id)
-                    try:
-                        ui_data = ui_client.get_screen_data()
-                        w, h = ui_data.width, ui_data.height
-                    except Exception:
-                        w, h = 1080, 2400
-                    local_ctx = ArtemisContext(
-                        trace_id="local-fallback",
-                        device=DeviceContext(
-                            host_platform=platform.os_type.name,
-                            mobile_platform=DevicePlatform.ANDROID,
-                            device_id=device_id,
-                            device_width=w,
-                            device_height=h,
-                        ),
-                        adb_client=adb,
-                        ui_adb_client=ui_client,
-                    )
-                    self._local_controller = UnifiedMobileController(local_ctx)
-            except Exception as le:
-                logger.error(f"Failed to setup local fallback controller: {le}")
-
-            return None
+        return await get_action_session(self.ctx)
 
     def _parse_decisions(self, structured_decisions: str) -> tuple[list[dict] | None, str | None]:
         if not structured_decisions:
@@ -270,20 +125,11 @@ class ValidatorNode:
         error_msg = ""
 
         while time.time() - start_time < timeout:
-            if session is not None:
-                result = await session.call_tool("take_screenshot", {})
-                success_img, content_img = self._parse_mcp_result(result)
-            elif getattr(self, "_local_controller", None):
-                try:
-                    content_img = await self._local_controller.take_screenshot()
-                    success_img = True
-                except Exception as e:
-                    success_img, content_img = False, str(e)
-            else:
-                success_img, content_img = (
-                    False,
-                    "No session or local controller",
-                )
+            try:
+                content_img = await session.screenshot_b64()
+                success_img = True
+            except Exception as e:
+                success_img, content_img = False, str(e)
             if success_img:
                 post_screenshot_b64 = content_img
                 img_before_bytes = base64.b64decode(pre_screenshot_b64)
@@ -465,15 +311,7 @@ class ValidatorNode:
 
                     # Capture the live mismatch screenshot to provide context for FailureAnalyzer
                     try:
-                        if session is not None:
-                            result = await session.call_tool("take_screenshot", {})
-                            success_img, content = self._parse_mcp_result(result)
-                            if success_img and content:
-                                post_screenshot_b64 = content
-                            else:
-                                logger.warning(f"Take screenshot via MCP returned non-success: {content}")
-                        elif getattr(self, "_local_controller", None):
-                            post_screenshot_b64 = await self._local_controller.take_screenshot()
+                        post_screenshot_b64 = await session.screenshot_b64()
                     except Exception as e:
                         logger.error(f"Failed to capture live screenshot for failure analysis: {e}")
                         post_screenshot_b64 = None
@@ -504,17 +342,9 @@ class ValidatorNode:
                     if not success and not post_screenshot_b64:
                         logger.info("Action failed, capturing failure screenshot...")
                         try:
-                            if session is not None:
-                                result = await session.call_tool("take_screenshot", {})
-                                success_img, content = self._parse_mcp_result(result)
-                                if success_img and content:
-                                    post_screenshot_b64 = content
-                                else:
-                                    logger.warning(f"Take failure screenshot via MCP returned non-success: {content}")
-                            elif getattr(self, "_local_controller", None):
-                                post_screenshot_b64 = await self._local_controller.take_screenshot()
+                            post_screenshot_b64 = await session.screenshot_b64()
                         except Exception as e:
-                            logger.error(f"Failed to capture failure screenshot: {e}")
+                            logger.error(f"Failed to capture failure screenshot: {e!r}")
                             post_screenshot_b64 = None
 
                 # Enrich and record execution
@@ -661,10 +491,9 @@ class ValidatorNode:
         try:
             return await self._execute_validation_loop(state)
         except asyncio.CancelledError:
-            logger.warning(
-                "Validator task cancelled. Instantly killing MCP server processes."
-            )
-            self._kill_mcp_server_instantly()
+            # In-process session teardown happens in ArtemisContext.__aexit__; there
+            # is no subprocess left to kill.
+            logger.warning("Validator task cancelled (Stop requested).")
             raise
         except Exception as e:
             err_stack = traceback.format_exc()
@@ -681,226 +510,42 @@ class ValidatorNode:
                     )
                 except Exception:
                     pass
-            self._kill_mcp_server_instantly()
             raise e
         finally:
             if self.ctx.data_engine:
                 self.ctx.data_engine.current_step_id = original_step_id
 
-    async def _exec_action(
-        self, session: ClientSession | None, action_item: dict
-    ) -> tuple[bool, str]:
+    async def _exec_action(self, session: ActionSession, action_item: dict) -> tuple[bool, str]:
+        """Executes one Operator action item through the unified action session.
+
+        The Operator's internal verbs (tap, long_press_on, focus_and_input_text, ...)
+        are translated to canonical tool calls in ``to_canonical_call`` using the
+        ``normalized_coordinates`` the Operator already computed. Success comes from
+        the structured ``ActionResult.ok`` -- no string parsing.
+        """
         action_name = action_item.get("action")
-        coordinates = action_item.get("coordinates")
 
-        # Intercept non-wait_for_text actions for local fallback
-        if session is None and getattr(self, "_local_controller", None) is not None:
-            ctrl = self._local_controller
-            logger.info(f"Executing in-process action fallback: {action_name}")
-            try:
-                if action_name == "tap":
-                    if coordinates and len(coordinates) == 2:
-                        times = action_item.get("times", 1)
-                        delay_ms = action_item.get("delay_ms", 100)
-                        res = await ctrl.tap_at(
-                            coordinates[0],
-                            coordinates[1],
-                            times=times,
-                            delay_ms=delay_ms,
-                        )
-                        return (True, "Success") if not res.error else (False, res.error)
-                    return False, "Invalid coords"
-                elif action_name == "long_press_on":
-                    d = action_item.get("duration", 1000)
-                    if coordinates and len(coordinates) == 2:
-                        res = await ctrl.tap_at(
-                            coordinates[0],
-                            coordinates[1],
-                            long_press=True,
-                            long_press_duration=d,
-                        )
-                        return (True, "Success") if not res.error else (False, res.error)
-                    return False, "Invalid coords"
-                elif action_name == "swipe":
-                    d = action_item.get("duration", 400)
-                    if coordinates and len(coordinates) == 4:
-                        err = await ctrl.swipe_coords(
-                            coordinates[0],
-                            coordinates[1],
-                            coordinates[2],
-                            coordinates[3],
-                            duration=d,
-                        )
-                        return (True, "Success") if not err else (False, str(err))
-                    return False, "Invalid coords"
-                elif action_name == "focus_and_input_text":
-                    t = action_item.get("text")
-                    clear_before = action_item.get("clear_before_input", False)
-                    if coordinates and len(coordinates) == 2:
-                        await ctrl.tap_at(coordinates[0], coordinates[1])
+        if action_name == "wait_for_delay":
+            time_in_ms = action_item.get("time_in_ms", 0)
+            logger.info(f"Validator performing wait_for_delay for {time_in_ms}ms...")
+            await asyncio.sleep(time_in_ms / 1000.0)
+            return True, ""
 
-                        await asyncio.sleep(0.5)
-                        if clear_before:
-                            await ctrl.erase_text()
-                        else:
-                            await ctrl.press_key("123")  # Move cursor to end for clean append
-                        success = await ctrl.type_text(t, clear_existing=False)
-                        return (True, "Success") if success else (False, "Failed typing")
-                    return False, "Invalid coords"
-                elif action_name == "focus_and_clear_text":
-                    if coordinates and len(coordinates) == 2:
-                        await ctrl.tap_at(coordinates[0], coordinates[1])
+        width = getattr(self.ctx.device, "device_width", 1080) if self.ctx.device else 1080
+        height = getattr(self.ctx.device, "device_height", 2400) if self.ctx.device else 2400
 
-                        await asyncio.sleep(0.5)
-                        success = await ctrl.erase_text()
-                        return (True, "Success") if success else (False, "Failed erase")
-                    return False, "Invalid coords"
-                elif action_name == "erase_one_char":
-                    success = await ctrl.erase_text(nb_chars=1)
-                    return (True, "Success") if success else (False, "Failed erase")
-                elif action_name == "press_key":
-                    keycode = action_item.get("keycode")
-                    success = await ctrl.press_key(keycode)
-                    return (True, "Success") if success else (False, f"Failed press {keycode}")
-                elif action_name == "back":
-                    success = await ctrl.go_back()
-                    return (True, "Success") if success else (False, "Failed back")
-                elif action_name == "launch_app":
-                    app_name = action_item.get("app_name")
-                    package_name = await find_package(self.ctx, app_name, use_fallback=False)
-                    if package_name:
-                        success, err_msg = await app_launch_utils.launch_app_with_retries(
-                            ctrl.ctx, package_name
-                        )
-                        return (True, "Success") if success else (False, err_msg)
-                    return False, "Package not found"
-                elif action_name == "stop_app":
-                    app_name = action_item.get("app_name")
-                    package_name = await find_package(self.ctx, app_name, use_fallback=False)
-                    if package_name:
-                        success = await ctrl.terminate_app(package_name)
-                        return (True, "Success") if success else (False, "Failed terminate")
-                    return False, "Package not found"
-                elif action_name == "open_link":
-                    url = action_item.get("url")
-                    success = await ctrl.open_url(url)
-                    return (True, "Success") if success else (False, "Failed open url")
-                elif action_name == "wait_for_delay":
-                    time_in_ms = action_item.get("time_in_ms", 0)
-
-                    await asyncio.sleep(time_in_ms / 1000.0)
-                    return True, ""
-                else:
-                    return (
-                        False,
-                        f"Unsupported action for local fallback: {action_name}",
-                    )
-            except Exception as e:
-                return False, f"In-process fallback failed: {e}"
-
-        # Normal MCP Execution Path
         try:
-            if action_name == "tap":
-                coordinates = action_item.get("coordinates")
-                times = action_item.get("times") or action_item.get("click_times") or 1
-                delay_ms = action_item.get("delay_ms") or action_item.get("delay") or 100
-                result = await session.call_tool(
-                    "tap",
-                    {
-                        "coordinates": coordinates,
-                        "times": times,
-                        "delay_ms": delay_ms,
-                    },
-                )
-                return self._parse_mcp_result(result)
+            tool_name, wire_args = to_canonical_call(action_item, dims=(width, height))
+        except ValueError as e:
+            return False, str(e)
 
-            elif action_name == "long_press_on":
-                coordinates = action_item.get("coordinates")
-                duration = action_item.get("duration", 1000)
-                result = await session.call_tool(
-                    "long_press_on",
-                    {"coordinates": coordinates, "duration": duration},
-                )
-                return self._parse_mcp_result(result)
-
-            elif action_name == "swipe":
-                coordinates = action_item.get("coordinates")
-                duration = action_item.get("duration", 400)
-                result = await session.call_tool(
-                    "swipe", {"coordinates": coordinates, "duration": duration}
-                )
-                return self._parse_mcp_result(result)
-
-            elif action_name == "focus_and_input_text":
-                coordinates = action_item.get("coordinates")
-                text = action_item.get("text", "")
-                clear_before_input = action_item.get("clear_before_input", False)
-                result = await session.call_tool(
-                    "focus_and_input_text",
-                    {
-                        "coordinates": coordinates,
-                        "text": text,
-                        "clear_before_input": clear_before_input,
-                    },
-                )
-                return self._parse_mcp_result(result)
-
-            elif action_name == "focus_and_clear_text":
-                coordinates = action_item.get("coordinates")
-                result = await session.call_tool(
-                    "focus_and_clear_text", {"coordinates": coordinates}
-                )
-                return self._parse_mcp_result(result)
-
-            elif action_name == "erase_one_char":
-                result = await session.call_tool("erase_one_char", {})
-                return self._parse_mcp_result(result)
-
-            elif action_name == "press_key":
-                keycode = action_item.get("keycode", "")
-                result = await session.call_tool("press_key", {"keycode": keycode})
-                return self._parse_mcp_result(result)
-
-            elif action_name == "back":
-                result = await session.call_tool("back", {})
-                return self._parse_mcp_result(result)
-
-            elif action_name == "launch_app":
-                app_name = action_item.get("app_name")
-                package_name = await find_package(self.ctx, app_name, use_fallback=False)
-                if not package_name:
-                    return False, f"Failed to find package for app: {app_name}"
-
-                success, err_msg = await app_launch_utils.launch_app_with_retries(
-                    self.ctx, package_name
-                )
-                return success, "Success" if success else err_msg
-
-            elif action_name == "stop_app":
-                app_name = action_item.get("app_name")
-                package_name = await find_package(self.ctx, app_name, use_fallback=False)
-                if not package_name:
-                    return False, f"Failed to find package for app: {app_name}"
-                result = await session.call_tool("stop_app", {"package_name": package_name})
-                return self._parse_mcp_result(result)
-
-            elif action_name == "open_link":
-                url = action_item.get("url")
-                result = await session.call_tool("open_link", {"url": url})
-                return self._parse_mcp_result(result)
-
-            elif action_name == "wait_for_delay":
-                time_in_ms = action_item.get("time_in_ms", 0)
-                logger.info(f"Validator performing wait_for_delay for {time_in_ms}ms...")
-
-                await asyncio.sleep(time_in_ms / 1000.0)
-                return True, ""
-
-            else:
-                return False, f"Unsupported action: {action_name}"
+        try:
+            res = await session.call(tool_name, wire_args)
         except Exception as e:
             return False, f"MCP call failed: {e}"
 
+        return (True, "") if res.ok else (False, res.message)
+
     @trace(type="tool", name="safety_net_validation")
     async def _validate_action_precondition(
         self, session, action_item: dict, state: State | None = None
@@ -1001,45 +646,21 @@ class ValidatorNode:
 
         try:
             elements = None
-            if session is not None:
-                try:
-                    result = await asyncio.wait_for(
-                        session.call_tool("get_ui_hierarchy", {}),
-                        timeout=VALIDATOR_UI_HIERARCHY_TIMEOUT,
-                    )
-                    if hasattr(result, "content") and result.content:
-                        text_content = (
-                            result.content[0].text
-                            if hasattr(result.content[0], "text")
-                            else str(result.content[0])
-                        )
-                        elements = json.loads(text_content)
-                except Exception as e:
-                    logger.warning(
-                        f"Failed to get live XML via MCP: {e}. Falling back to"
-                        " Pixel-based validation."
-                    )
-                    return (
-                        False,
-                        ValidationErrorCategory.XML_BYPASSED,
-                        f"XML hierarchy fetch timed out or errored: {e}",
-                    )
-            elif getattr(self, "_local_controller", None):
-                try:
-                    elements = await asyncio.wait_for(
-                        self._local_controller.get_ui_elements(),
-                        timeout=VALIDATOR_UI_HIERARCHY_TIMEOUT,
-                    )
-                except Exception as e:
-                    logger.warning(
-                        f"Failed to get live XML via local controller: {e}."
-                        " Falling back to Pixel-based validation."
-                    )
-                    return (
-                        False,
-                        ValidationErrorCategory.XML_BYPASSED,
-                        f"XML hierarchy fetch timed out or errored: {e}",
-                    )
+            try:
+                # The timeout must ride inside the session (MCP read timeout), never an
+                # outer asyncio.wait_for: cancelling call_tool mid-flight corrupts the
+                # in-memory transport and bricks the session for all later callers.
+                elements = await session.ui_hierarchy(timeout=VALIDATOR_UI_HIERARCHY_TIMEOUT)
+            except Exception as e:
+                logger.warning(
+                    f"Failed to get live XML via MCP: {e!r}. Falling back to"
+                    " Pixel-based validation."
+                )
+                return (
+                    False,
+                    ValidationErrorCategory.XML_BYPASSED,
+                    f"XML hierarchy fetch timed out or errored: {e!r}",
+                )
 
             if not elements or not isinstance(elements, list):
                 logger.warning(
@@ -1275,6 +896,9 @@ class ValidatorNode:
                         f" {new_coords}."
                     )
                     action_item["coordinates"] = new_coords
+                    # Drop the now-stale normalized coordinates so the canonical
+                    # translation re-derives them from the healed pixel center.
+                    action_item.pop("normalized_coordinates", None)
             else:
                 logger.info(
                     "Pre-execution validation SUCCESS"
@@ -1435,23 +1059,6 @@ class ValidatorNode:
 
         return passed, category, reason
 
-    def _parse_mcp_result(self, result) -> tuple[bool, str]:
-        """Helper to parse MCP tool result."""
-        if hasattr(result, "content") and result.content:
-            text_content = (
-                result.content[0].text
-                if hasattr(result.content[0], "text")
-                else str(result.content[0])
-            )
-            if text_content.startswith("Error:") or text_content.startswith("Failed:"):
-                return False, text_content
-            elif text_content == "Success":
-                return True, ""
-            elif text_content == "Failed":
-                return False, "Action failed on server"
-            return True, text_content
-        return True, ""
-
     @trace(type="tool", name="safety_net_pixel_validation")
     async def _validate_action_precondition_pixel(
         self,
@@ -1535,13 +1142,10 @@ class ValidatorNode:
             try:
                 # A. Take fresh live screenshot (captures state changes / dynamic loading settling)
                 live_screenshot_b64 = None
-                if session is not None:
-                    result = await session.call_tool("take_screenshot", {})
-                    success_img, live_screenshot_b64 = self._parse_mcp_result(result)
-                elif getattr(self, "_local_controller", None):
-                    live_screenshot_b64 = await self._local_controller.take_screenshot()
+                try:
+                    live_screenshot_b64 = await session.screenshot_b64()
                     success_img = True
-                else:
+                except Exception:
                     success_img, live_screenshot_b64 = False, None
 
                 if not success_img or not live_screenshot_b64:

artemis/context.py

@@ -176,11 +176,26 @@ class ArtemisContext(BaseModel):
     _mobile_controller: Any | None = PrivateAttr(default=None)
     mcp_client_ctx: Any | None = None
     mcp_session: Any | None = None
+    action_session: Any | None = None
+    """In-process unified action MCP session (artemis.mcp.action_session)."""
+    actuator: Any | None = None
+    """Optional actuator backend override (artemis.mcp.actuators). ``None`` selects
+    the default AdbActuator; installing e.g. a robot-arm backend happens here."""
 
     async def __aenter__(self) -> ArtemisContext:
         return self
 
     async def __aexit__(self, exc_type, exc_val, exc_tb):
+        # Close the in-process action session before draining background tasks so its
+        # owner task exits cleanly rather than being cancelled below.
+        if self.action_session is not None:
+            try:
+                await self.action_session.aclose()
+            except Exception:
+                pass
+            finally:
+                self.action_session = None
+
         if self.background_tasks:
             tasks = list(self.background_tasks)
             pending_tasks = [task for task in tasks if not task.done()]

artemis/interfaces/cli/commands/mcp.py

@@ -157,11 +157,15 @@ def _get_config_snippet(client: str, python_exe: str, project_root: str) -> dict
         return {"mcpServers": {"artemis": config_body}}
 
 
-def _parse_json_lenient(text: str) -> dict:
-    """Parses JSON or JSONC (JSON with comments / trailing commas) safely."""
+def _parse_json_lenient(text: str) -> dict | None:
+    """Parses JSON or JSONC (JSON with comments / trailing commas) safely.
+
+    Returns ``None`` when the text cannot be parsed as a JSON object, so callers
+    can tell a genuinely empty ``{}`` file apart from a corrupt one.
+    """
     try:
         data = json.loads(text)
-        return data if isinstance(data, dict) else {}
+        return data if isinstance(data, dict) else None
     except Exception:
         pass
     # Remove // single-line comments
@@ -172,9 +176,9 @@ def _parse_json_lenient(text: str) -> dict:
     cleaned = re.sub(r",\s*([}\]])", r"\1", cleaned)
     try:
         data = json.loads(cleaned)
-        return data if isinstance(data, dict) else {}
+        return data if isinstance(data, dict) else None
     except Exception:
-        return {}
+        return None
 
 
 def _merge_json_file(
@@ -183,15 +187,29 @@ def _merge_json_file(
     server_config: dict,
     key_name: str | tuple[str, ...] = "mcpServers",
     remove_paths: tuple[tuple[str, ...], ...] = (),
+    strict_parse: bool = False,
 ) -> bool:
-    """Merges server configuration into a target JSON file without overwriting existing servers."""
+    """Merges server configuration into a target JSON file without overwriting existing servers.
+
+    With ``strict_parse=True``, an existing non-empty file that cannot be parsed
+    aborts the merge instead of being replaced. Use this for files that hold
+    state beyond MCP config (e.g. ~/.claude.json), where a degraded rewrite
+    would destroy unrelated data.
+    """
     try:
         file_path.parent.mkdir(parents=True, exist_ok=True)
         data: dict = {}
         if file_path.exists() and file_path.stat().st_size > 0:
             raw_text = file_path.read_text(encoding="utf-8")
-            data = _parse_json_lenient(raw_text)
-            if not data and raw_text.strip():
+            parsed = _parse_json_lenient(raw_text)
+            data = parsed or {}
+            if parsed is None and raw_text.strip():
+                if strict_parse:
+                    logger.warning(
+                        f"Existing JSON in {file_path} could not be parsed; refusing to rewrite it. "
+                        "Fix or remove the file, then re-run the install."
+                    )
+                    return False
                 # Backup unparseable existing file to prevent accidental loss
                 backup_path = file_path.with_suffix(file_path.suffix + ".bak")
                 try:
@@ -305,6 +323,36 @@ def _merge_codex_toml(file_path: Path, server_config: dict) -> bool:
         return False
 
 
+def _remove_rules_block(file_path: Path) -> bool:
+    """Removes a previously injected managed ARTEMIS block from a rules file.
+
+    Used to migrate clients that load both their main rules file and a
+    standalone rule file (e.g. Claude Code loads ~/.claude/CLAUDE.md AND
+    ~/.claude/rules/*.md), where keeping the injected block would duplicate
+    the rules in the model's context. If the file contains nothing but the
+    managed block, the file is deleted entirely.
+    """
+    try:
+        if not file_path.exists():
+            return True
+        begin_marker = "<!-- BEGIN ARTEMIS MOBILE TESTING RULES -->"
+        end_marker = "<!-- END ARTEMIS MOBILE TESTING RULES -->"
+        existing = file_path.read_text(encoding="utf-8")
+        if begin_marker not in existing or end_marker not in existing:
+            return True
+        prefix = existing.split(begin_marker)[0]
+        suffix = existing.split(end_marker)[1]
+        remainder = f"{prefix.rstrip()}\n\n{suffix.lstrip()}".strip()
+        if remainder:
+            file_path.write_text(remainder + "\n", encoding="utf-8")
+        else:
+            file_path.unlink()
+        return True
+    except Exception as e:
+        logger.warning(f"Could not remove rules block from {file_path}: {e}")
+        return False
+
+
 def _inject_rules_block(file_path: Path, content: str) -> bool:
     """Injects or updates a managed ARTEMIS block in a global rules file without overwriting user content."""
     try:
@@ -419,13 +467,22 @@ def install_rules(client: str, project_root: str) -> list[str]:
                 installed_paths.append(str(cursor_rules_file))
             if _write_cursor_mdc(global_mdc, raw_rules):
                 installed_paths.append(str(global_mdc))
-        elif target in ("claude", "claude_code", "claude_desktop"):
+        elif target in ("claude", "claude_code"):
+            # Claude Code loads BOTH ~/.claude/CLAUDE.md and ~/.claude/rules/*.md
+            # into context every session, so install the rules in exactly one
+            # place (the standalone rule file) and migrate away any block a
+            # previous version injected into CLAUDE.md.
             claude_md = Path.home() / ".claude" / "CLAUDE.md"
             global_rule = Path.home() / ".claude" / "rules" / "artemis.md"
-            if _inject_rules_block(claude_md, raw_rules):
-                installed_paths.append(str(claude_md))
+            _remove_rules_block(claude_md)
             if _write_rule_file(global_rule, raw_rules):
                 installed_paths.append(str(global_rule))
+        elif target == "claude_desktop":
+            # Claude Desktop only reads ~/.claude/CLAUDE.md (not rules/*.md), so
+            # the rules block stays injected there for this target.
+            claude_md = Path.home() / ".claude" / "CLAUDE.md"
+            if _inject_rules_block(claude_md, raw_rules):
+                installed_paths.append(str(claude_md))
         elif target == "windsurf":
             global_rule = Path.home() / ".codeium" / "windsurf" / "rules" / "artemis.md"
             global_mem = Path.home() / ".codeium" / "windsurf" / "memories" / "global_rules.md"
@@ -516,9 +573,11 @@ def install_mcp_config(client: str, python_exe: str, project_root: str) -> list[
             if _merge_json_file(claude_path, "artemis", server_cfg):
                 installed_paths.append(str(claude_path))
 
-            # Also install to Claude Code CLI global config (~/.claude.json)
+            # Also install to Claude Code CLI global config (~/.claude.json).
+            # This file holds Claude Code state well beyond MCP config, so a
+            # parse failure must abort the merge rather than rewrite the file.
             claude_code_path = Path.home() / ".claude.json"
-            if _merge_json_file(claude_code_path, "artemis", server_cfg):
+            if _merge_json_file(claude_code_path, "artemis", server_cfg, strict_parse=True):
                 installed_paths.append(str(claude_code_path))
         elif target == "cursor":
             server_cfg = snippet["mcpServers"]["artemis"]
@@ -737,10 +796,16 @@ def mcp_command(
             else:
                 agent_mcp.run(transport="stdio")
         elif st == "adb":
-            logger.info(f"Starting Artemis ADB MCP Server over {transport}...")
             if transport.lower() == "sse":
+                logger.info(f"Starting Artemis ADB MCP Server over {transport}...")
                 adb_mcp.run(transport="sse", host=host, port=port)
             else:
+                # stdio carries the MCP JSON-RPC stream: redirect logging and detach
+                # from the parent DataEngine before any output can corrupt it.
+                from artemis.mcp.adb_server import configure_stdio_mode
+
+                configure_stdio_mode()
+                logger.info("Starting Artemis ADB MCP Server over stdio...")
                 adb_mcp.run(transport="stdio")
         elif st == "xml":
             from artemis.mcp.xml_search_server import mcp as xml_mcp

artemis/mcp/action_executor.py

@@ -0,0 +1,546 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""MCP-backed action executor for FlashRunner and FailureAnalyzer.
+
+Same public contract as the legacy ``MobileActionExecutor`` --
+``execute(name, args, tool_call_id, state) -> ToolExecutionResult`` -- but execution
+routes through the in-process action MCP session, and dispatch is table-driven so a
+backend's extension tools are callable without touching this file.
+
+Kept agent-side (by design, not omission): argument normalization, element-index
+resolution against LangGraph ``State``, smart-swipe resolution, act-then-observe
+capture and ``State`` write-back, tracing (a ``ContextVar`` cannot cross the server's
+task boundary -- see the plan's R2), and the non-device tools (``read_note``,
+``list_notes``, ``ask_explorer``).
+
+Status is carried by ``ActionResult.ok`` -- the historical substring sniffing on
+``"Error"``/``"Failed"`` is gone, so typing the literal text "Failed" into a field no
+longer marks the step as failed, and a successful tap with a failed screenshot is no
+longer misreported as an error.
+"""
+
+import ast
+import hashlib
+import json
+from pathlib import Path
+from typing import Any
+
+from artemis.config import resolve_explorer_version
+from artemis.context import ArtemisContext
+from artemis.controllers.unified_controller import UnifiedMobileController
+from artemis.data_engine.trace import TraceSpan
+from artemis.mcp.action_manifest import OPTIONAL_ACTIONS, REQUIRED_ACTIONS
+from artemis.mcp.action_session import ActionSession, get_action_session
+from artemis.mcp.action_types import ActionCode, ActionResult
+from artemis.mcp.actuators.adb import AdbActuator
+from artemis.agents.validator.tool_declarations import (
+    ToolExecutionResult,
+    normalize_coordinate_target,
+)
+from artemis.utils.coordinates import (
+    compute_smart_swipe_coordinates,
+    parse_swipe_parameters,
+)
+from artemis.utils.logger import get_logger
+from artemis.utils.notes import (
+    format_list_notes_failure,
+    format_list_notes_success,
+    format_read_note_failure,
+    list_notes_info,
+    read_note_content,
+)
+
+logger = get_logger(__name__)
+
+__all__ = ["McpActionExecutor"]
+
+# Wording for wrapped exceptions; matches the historical executor `except` arms.
+_EXCEPTION_PREFIX = {
+    "click": "Error during click",
+    "click_sequence": "Error executing click sequence",
+    "long_press": "Error during long press",
+    "input_text": "Error during input text",
+    "swipe": "Error during swipe",
+    "press_key": "Error during press_key",
+    "manage_app": "Error during manage_app",
+    "wait_for_delay": "Error during wait_for_delay",
+    "wait_for_text": "Error during wait_for_text",
+}
+
+
+class _ArgError(ValueError):
+    """Argument-translation failure whose message is already fully formatted."""
+
+
+class McpActionExecutor:
+    """Routes agent tool calls through the unified action MCP session."""
+
+    def __init__(
+        self,
+        ctx: ArtemisContext,
+        controller: UnifiedMobileController | None = None,
+        actuator: AdbActuator | None = None,
+    ):
+        self.ctx = ctx
+        self.actuator = (
+            actuator or getattr(ctx, "actuator", None) or AdbActuator(ctx, controller)
+        )
+        self.controller = self.actuator.controller
+        self._session: ActionSession | None = None
+
+    @property
+    def action_tool_names(self) -> frozenset[str]:
+        """Device actions plus backend extension names -- the dynamic dispatch set."""
+        return (
+            (REQUIRED_ACTIONS | OPTIONAL_ACTIONS)
+            | {e.name for e in self.actuator.extensions()}
+        )
+
+    async def _session_or_start(self) -> ActionSession:
+        if self._session is None or not self._session.started:
+            self._session = await get_action_session(self.ctx, actuator=self.actuator)
+        return self._session
+
+    # --- Public entry ----------------------------------------------------------------
+
+    async def execute(
+        self,
+        name: str,
+        args: dict[str, Any],
+        tool_call_id: str,
+        state: Any,
+    ) -> ToolExecutionResult:
+        """Executes the named tool and wraps the outcome for the calling agent."""
+        raw_name = name.split(":")[-1] if ":" in name else name
+
+        if raw_name in ("read_note", "list_notes", "ask_explorer"):
+            return await self._execute_agent_tool(raw_name, name, args, tool_call_id, state)
+
+        if raw_name in self.action_tool_names:
+            return await self._execute_device_action(
+                raw_name, name, args, tool_call_id, state
+            )
+
+        return ToolExecutionResult(
+            tool_call_id=tool_call_id,
+            tool_name=name,
+            status="error",
+            text_summary=f"Error: Tool '{name}' not supported.",
+        )
+
+    # --- Device actions --------------------------------------------------------------
+
+    async def _execute_device_action(
+        self,
+        raw_name: str,
+        name: str,
+        args: dict[str, Any],
+        tool_call_id: str,
+        state: Any,
+    ) -> ToolExecutionResult:
+        span = TraceSpan(name=raw_name, trace_type="action", ctx=self.ctx)
+        span.payload = {"args": args}
+
+        message = ""
+        res: ActionResult | None = None
+        img_bytes: bytes | None = None
+        shot_path: str | None = None
+        xml_list: str | None = None
+
+        with span:
+            try:
+                session = await self._session_or_start()
+                wire_name, wire_args, finalize = self._translate(raw_name, args, state)
+                extension = raw_name not in (REQUIRED_ACTIONS | OPTIONAL_ACTIONS)
+
+                if extension:
+                    raw_result = await session.call_raw(wire_name, wire_args)
+                    message = next(
+                        (b.text for b in raw_result.content if getattr(b, "type", "") == "text"),
+                        f"Extension tool '{raw_name}' completed.",
+                    )
+                    res = ActionResult.success(raw_name, message)
+                else:
+                    res = await session.call(wire_name, wire_args)
+                    message = finalize(res) if finalize else res.message
+
+                if res.ok or self._observe_despite_failure(raw_name, res):
+                    obs = await session.observe(settle_ms=400)
+                    if obs.ok:
+                        shot_path = obs.screenshot_path
+                        xml_list = obs.elements_text
+                        if obs.hierarchy_ok:
+                            state.indexed_points = [el["center"] for el in obs.elements]
+                            state.indexed_elements = obs.elements
+                        if shot_path:
+                            try:
+                                img_bytes = Path(shot_path).read_bytes()
+                            except Exception as read_err:
+                                logger.warning(
+                                    f"Failed to read observed screenshot: {read_err}"
+                                )
+            except _ArgError as e:
+                res = ActionResult.failure(raw_name, str(e), code=ActionCode.INVALID_ARGS)
+                message = str(e)
+            except Exception as e:
+                prefix = _EXCEPTION_PREFIX.get(raw_name, f"Error during {raw_name}")
+                message = f"{prefix}: {e}"
+                res = ActionResult.failure(raw_name, message, detail=repr(e))
+
+            if shot_path:
+                state.latest_screenshot = shot_path
+
+            status = "success" if res.ok else "error"
+            post_image_name = None
+            if shot_path:
+                post_image_name = Path(shot_path).stem
+            elif img_bytes:
+                post_image_name = hashlib.sha256(img_bytes).hexdigest()
+            span.result = {
+                "outcome": message,
+                "post_image_name": post_image_name,
+                "has_xml": bool(xml_list),
+                "status": status,
+            }
+            if status == "error":
+                span.status = "failed"
+                span.error = message
+
+        return ToolExecutionResult(
+            tool_call_id=tool_call_id,
+            tool_name=name,
+            status=status,
+            text_summary=message,
+            screenshot_bytes=img_bytes,
+            screenshot_path=shot_path,
+            ui_elements_text=xml_list,
+            metadata={
+                "code": res.code.value,
+                "normalized_coordinates": res.normalized_coordinates,
+            },
+        )
+
+    @staticmethod
+    def _observe_despite_failure(raw_name: str, res: ActionResult) -> bool:
+        """Failures that still observe the screen, mirroring the legacy executor.
+
+        A failed app launch and a wait_for_text timeout captured the screen; argument
+        and package errors returned without one.
+        """
+        if raw_name == "manage_app":
+            return res.code not in (ActionCode.PACKAGE_NOT_FOUND, ActionCode.INVALID_ARGS)
+        if raw_name == "wait_for_text":
+            return res.code is ActionCode.TIMEOUT
+        return False
+
+    # --- Argument translation --------------------------------------------------------
+
+    def _translate(
+        self, raw_name: str, args: dict[str, Any], state: Any
+    ) -> tuple[str, dict[str, Any], Any]:
+        """Maps agent-facing args to wire args; returns (name, args, finalize).
+
+        ``finalize(res)`` post-processes the ActionResult message where the historical
+        wording depended on client-side context (direction swipes).
+        """
+        if raw_name == "click":
+            target = self._require_pair(
+                args.get("target") or args.get("coordinates") or [], "click"
+            )
+            return (
+                "click",
+                {
+                    "target": list(target),
+                    "times": args.get("times", 1),
+                    "delay_ms": args.get("delay_ms", 100),
+                },
+                None,
+            )
+
+        if raw_name == "long_press":
+            target = self._require_pair(
+                args.get("target") or args.get("coordinates") or [], "long press"
+            )
+            return (
+                "long_press",
+                {
+                    "target": list(target),
+                    "duration_ms": args.get("duration_ms", args.get("duration", 1000)),
+                },
+                None,
+            )
+
+        if raw_name == "input_text":
+            raw_target = args.get("target") or args.get("coordinates")
+            target = None
+            if raw_target:
+                target = list(self._require_pair(raw_target, "input text"))
+            return (
+                "input_text",
+                {
+                    "text": args.get("text", ""),
+                    "target": target,
+                    "clear_exist": args.get("clear_exist", True),
+                },
+                None,
+            )
+
+        if raw_name == "click_sequence":
+            return (
+                "click_sequence",
+                {
+                    "sequence": self._resolve_sequence(args.get("sequence") or [], state),
+                    "delay_ms": args.get("delay_ms", 50),
+                },
+                None,
+            )
+
+        if raw_name == "swipe":
+            return self._translate_swipe(args, state)
+
+        if raw_name == "press_key":
+            return "press_key", {"key": args.get("key", "BACK")}, None
+
+        if raw_name == "manage_app":
+            return (
+                "manage_app",
+                {
+                    "action": args.get("action", "launch"),
+                    "app_name": args.get("app_name", ""),
+                },
+                None,
+            )
+
+        if raw_name == "wait_for_delay":
+            return "wait_for_delay", {"time_in_ms": args.get("time_in_ms", 1000)}, None
+
+        if raw_name == "wait_for_text":
+            return (
+                "wait_for_text",
+                {
+                    "text": args.get("text", ""),
+                    "wait_state": args.get("wait_state") or "appear",
+                    "timeout_ms": args.get("timeout_ms", 5000),
+                },
+                None,
+            )
+
+        # Backend extension: pass the arguments straight through.
+        return raw_name, dict(args), None
+
+    @staticmethod
+    def _require_pair(raw: Any, label: str) -> tuple[int, int]:
+        target = normalize_coordinate_target(raw)
+        if not isinstance(target, (list, tuple)) or len(target) != 2:
+            prefix = {
+                "click": "Error during click",
+                "long press": "Error during long press",
+                "input text": "Error during input text",
+            }[label]
+            raise _ArgError(f"{prefix}: Invalid target format: {raw}")
+        return int(target[0]), int(target[1])
+
+    def _resolve_sequence(self, sequence: Any, state: Any) -> list[list[int]]:
+        """Resolves click_sequence entries (indices or pairs) to normalized pairs."""
+        if isinstance(sequence, str):
+            sequence_str = sequence.strip()
+            try:
+                sequence = json.loads(sequence_str)
+            except Exception:
+                try:
+                    sequence = ast.literal_eval(sequence_str)
+                except Exception:
+                    pass
+
+        if not isinstance(sequence, (list, tuple)):
+            raise _ArgError(
+                f"Error during click sequence: Invalid sequence format: {sequence}"
+            )
+
+        width = getattr(self.ctx.device, "device_width", 1080) if self.ctx.device else 1080
+        height = getattr(self.ctx.device, "device_height", 2400) if self.ctx.device else 2400
+
+        resolved: list[list[int]] = []
+        for raw_target in sequence:
+            target = normalize_coordinate_target(raw_target)
+            if isinstance(target, int):
+                idx = target
+                points = getattr(state, "indexed_points", []) or []
+                if not 1 <= idx <= len(points):
+                    raise _ArgError(
+                        "Error during click sequence: Index"
+                        f" {idx} is out of range (available: {len(points)})"
+                    )
+                px, py = int(points[idx - 1][0]), int(points[idx - 1][1])
+                nx = int(max(0, min(1000, round(px * 1000 / max(1, width)))))
+                ny = int(max(0, min(1000, round(py * 1000 / max(1, height)))))
+            elif isinstance(target, (list, tuple)) and len(target) == 2:
+                nx, ny = int(target[0]), int(target[1])
+            else:
+                raise _ArgError(
+                    f"Error during click sequence: Invalid target format: {raw_target}"
+                )
+            resolved.append([nx, ny])
+        return resolved
+
+    def _translate_swipe(
+        self, args: dict[str, Any], state: Any
+    ) -> tuple[str, dict[str, Any], Any]:
+        width = getattr(self.ctx.device, "device_width", 1080) if self.ctx.device else 1080
+        height = getattr(self.ctx.device, "device_height", 2400) if self.ctx.device else 2400
+        default_duration = args.get("duration", 400)
+        kind, target, final_duration = parse_swipe_parameters(
+            dict(args), default_duration=default_duration
+        )
+
+        if kind == "direction":
+            dir_name = target
+            x1, y1, x2, y2, smart_dur = compute_smart_swipe_coordinates(
+                direction=target,
+                target=args.get("target"),
+                indexed_elements=getattr(state, "indexed_elements", None) if state else None,
+                ui_hierarchy=getattr(state, "ui_tree", None) if state else None,
+                width=width,
+                height=height,
+                duration=final_duration,
+            )
+
+            def _norm(v: float, size: int) -> int:
+                return int(max(0, min(1000, round(v * 1000 / max(1, size)))))
+
+            def finalize(res: ActionResult) -> str:
+                if not res.ok:
+                    return f"Error swiping {dir_name}: {res.detail}"
+                return f"Swipe completed successfully. Swiped {dir_name}."
+
+            return (
+                "swipe",
+                {
+                    "start": [_norm(x1, width), _norm(y1, height)],
+                    "end": [_norm(x2, width), _norm(y2, height)],
+                    "duration_ms": smart_dur,
+                },
+                finalize,
+            )
+
+        if kind == "coords":
+            x1, y1, x2, y2 = target
+
+            def finalize(res: ActionResult) -> str:
+                if not res.ok:
+                    return f"Error dragging: {res.detail}"
+                return (
+                    "Swipe completed successfully. Swiped from"
+                    f" [{x1}, {y1}] to [{x2}, {y2}]."
+                )
+
+            return (
+                "swipe",
+                {
+                    "start": [int(x1), int(y1)],
+                    "end": [int(x2), int(y2)],
+                    "duration_ms": final_duration,
+                },
+                finalize,
+            )
+
+        raise _ArgError(f"Error during swipe: Invalid direction: {args}")
+
+    # --- Non-device tools (stay agent-side) ------------------------------------------
+
+    async def _execute_agent_tool(
+        self,
+        raw_name: str,
+        name: str,
+        args: dict[str, Any],
+        tool_call_id: str,
+        state: Any,
+    ) -> ToolExecutionResult:
+        span = TraceSpan(name=raw_name, trace_type="tool", ctx=self.ctx)
+        span.payload = {"args": args}
+        with span:
+            if raw_name == "read_note":
+                text = await self._read_note(
+                    args.get("key", ""), args.get("start_line"), args.get("end_line")
+                )
+            elif raw_name == "list_notes":
+                text = await self._list_notes()
+            else:
+                text = await self._ask_explorer(
+                    args.get("query") or args.get("task_description") or "",
+                    args.get("context_feedback"),
+                    state,
+                )
+            span.result = {"outcome": text}
+
+        # These texts come from our own failure formatters, so the historical
+        # "Error" marker check is reliable here (unlike free-form device output).
+        return ToolExecutionResult(
+            tool_call_id=tool_call_id,
+            tool_name=name,
+            status="error" if "Error" in (text or "") else "success",
+            text_summary=text,
+        )
+
+    async def _read_note(
+        self, key: str, start_line: int | None, end_line: int | None
+    ) -> str:
+        try:
+            base_dir = self.ctx.data_engine.base_dir if self.ctx.data_engine else None
+            if not base_dir:
+                return format_read_note_failure(key, "DataEngine not initialized.")
+            return read_note_content(base_dir, key, start_line, end_line)
+        except Exception as e:
+            return format_read_note_failure(key, str(e))
+
+    async def _list_notes(self) -> str:
+        try:
+            base_dir = self.ctx.data_engine.base_dir if self.ctx.data_engine else None
+            if not base_dir:
+                return format_list_notes_failure("DataEngine not initialized.")
+            return format_list_notes_success(list_notes_info(base_dir))
+        except Exception as e:
+            return format_list_notes_failure(str(e))
+
+    async def _ask_explorer(
+        self, query: str, context_feedback: str | None, state: Any
+    ) -> str:
+        # Imported lazily: the explorer stack is heavy and recursive (it spawns an LLM
+        # sub-agent), which is also why it must never live behind the action server.
+        from artemis.tools.explorer_tool import _run_explorer_logic
+
+        try:
+            active_version = resolve_explorer_version(
+                self.ctx,
+                explicit_version=None,
+                agent_or_profile_name="validator",
+            )
+            result = await _run_explorer_logic(
+                self.ctx,
+                state,
+                query,
+                context_feedback or "",
+                version=active_version,
+            )
+            if isinstance(result, list):
+                texts = [
+                    item["text"]
+                    for item in result
+                    if isinstance(item, dict) and item.get("type") == "text"
+                ]
+                return "\n".join(texts) if texts else str(result)
+            return str(result)
+        except Exception as e:
+            return f"Error executing ask_explorer: {e}"

artemis/mcp/action_manifest.py

@@ -0,0 +1,319 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Contract layer between actuator backends and the agent-facing tool surface.
+
+This module is the single place that declares *what a backend must provide*. It sits
+between the actuator implementations (``artemis/mcp/actuators/``) and the agents that
+consume tools, so that a backend -- ADB today, a robot arm tomorrow -- can omit tools
+it cannot perform, and add tools nobody anticipated, without any agent knowing.
+
+Two rules govern the split between required and optional:
+
+1. A tool is REQUIRED only when a prompt depends on it *structurally*, i.e. the prompt
+   cannot be assembled around its absence. Today that is ``click_sequence`` alone: the
+   two ``*_disappeared_analyzer.md`` prompts are built around "atomic chained execution
+   to defeat turn latency", which *is* ``click_sequence``.
+2. Everything else is OPTIONAL, because every other prompt reference lives in a tool
+   enumeration slot or a self-contained instruction block that the assembly layer
+   (``artemis/agents/prompt_assembly.py``) renders conditionally. An optional tool that
+   a backend does not implement disappears from the declarations *and* from the prompt,
+   so it costs the model nothing.
+
+``tests/unit/mcp/test_action_manifest.py`` re-derives rule 2 by scanning the prompt
+sources, so adding a tool name to a prompt without classifying it here fails CI.
+"""
+
+from collections.abc import Awaitable, Callable
+from dataclasses import dataclass, field
+from typing import Any
+
+__all__ = [
+    "ActuatorContractError",
+    "AGENT_ROLES",
+    "ALL_KNOWN_TOOLS",
+    "BACKEND_INDEPENDENT_TOOLS",
+    "DEVICE_ACTIONS",
+    "ExtensionTool",
+    "INTERNAL_ACTIONS",
+    "MIN_EXTENSION_DESCRIPTION_LENGTH",
+    "OPTIONAL_ACTIONS",
+    "REQUIRED_ACTIONS",
+    "available_device_actions",
+    "filter_declarations",
+    "validate_actuator",
+]
+
+
+# --- Tool classification -------------------------------------------------------------
+
+#: Device actions a backend MUST implement. See rule 1 in the module docstring.
+#:
+#: ``click_sequence`` implies the ability to tap, so a backend providing it can
+#: trivially provide ``click`` as well; ``click`` is nonetheless optional because no
+#: prompt depends on it structurally once the enumeration slots are assembled.
+REQUIRED_ACTIONS: frozenset[str] = frozenset(
+    {
+        "click_sequence",
+    }
+)
+
+#: Device actions a backend MAY implement. Absent ones vanish from both the tool
+#: declarations and the rendered prompts.
+OPTIONAL_ACTIONS: frozenset[str] = frozenset(
+    {
+        "click",
+        "long_press",
+        "input_text",
+        "swipe",
+        "press_key",
+        "manage_app",
+        "wait_for_delay",
+        # The four below appear in no prompt at all. `wait_for_text` corroborates the
+        # classification: it is listed in the legacy ACTION_TOOL_NAMES but has never had
+        # a ToolDeclaration, i.e. it has always been unreachable by any LLM.
+        "wait_for_text",
+        "open_link",
+        "erase_one_char",
+        "focus_and_clear_text",
+    }
+)
+
+#: Used by the client-side adapter only; never declared to any LLM, so the
+#: "no cognitive load" rule does not apply. The adapter cannot function without them,
+#: so they are validated as strictly as REQUIRED_ACTIONS.
+INTERNAL_ACTIONS: frozenset[str] = frozenset(
+    {
+        "observe_screen",
+        "take_screenshot",
+        "get_ui_hierarchy",
+    }
+)
+
+#: Tools that are not device control at all -- notes, sub-agents, diagnostics, and the
+#: loop-termination sentinels. They are unaffected by which actuator is installed.
+#:
+#: ``run_adb_command`` and ``manage_app`` ride the *system channel* rather than physical
+#: actuation: a robot arm driving a handset still has ADB attached, so ``am start``
+#: suffices and no icon-hunting is required. (``manage_app`` is nonetheless classified
+#: as an optional device action above, since it is declared through the same path.)
+BACKEND_INDEPENDENT_TOOLS: frozenset[str] = frozenset(
+    {
+        "read_note",
+        "list_notes",
+        "save_note",
+        "update_note",
+        "append_note",
+        "ask_explorer",
+        "ask_diagnoser",
+        "ask_committee",
+        "video_analyzer",
+        "run_adb_command",
+        "manage_task",
+        "analyze_task_output",
+        "reply_to_checker",
+        "report_task_status",
+        "report_failure_analysis",
+    }
+)
+
+#: Everything an actuator may legitimately claim in ``capabilities()``.
+DEVICE_ACTIONS: frozenset[str] = REQUIRED_ACTIONS | OPTIONAL_ACTIONS | INTERNAL_ACTIONS
+
+#: Every name the manifest knows about. Extension tools must not collide with these.
+ALL_KNOWN_TOOLS: frozenset[str] = DEVICE_ACTIONS | BACKEND_INDEPENDENT_TOOLS
+
+#: Agent roles an extension tool may target.
+AGENT_ROLES: frozenset[str] = frozenset(
+    {
+        "operator",
+        "flash",
+        "failure_analyzer",
+        "validator",
+    }
+)
+
+#: Extension descriptions carry the entire usage contract (see ``ExtensionTool``), so a
+#: one-word description is a bug rather than a terse style choice.
+MIN_EXTENSION_DESCRIPTION_LENGTH = 40
+
+
+class ActuatorContractError(RuntimeError):
+    """Raised when an actuator does not satisfy the manifest contract.
+
+    Always raised at session start rather than mid-run, so a misconfigured backend
+    fails before the agent has taken any action on the device.
+    """
+
+
+@dataclass(frozen=True)
+class ExtensionTool:
+    """A tool contributed by a backend that the manifest does not know about.
+
+    Extension tools are invisible to the prompt layer by construction: prompts are
+    static text that cannot anticipate future backends, so an extension gets **no**
+    prompt-level teaching. Its ``description`` must therefore be self-contained --
+    stating when to reach for it and what it does -- or the model will never use it
+    correctly. :func:`validate_actuator` enforces a length floor as a crude guard.
+    """
+
+    name: str
+    description: str
+    input_schema: dict[str, Any]
+    handler: Callable[..., Awaitable[Any]]
+    targets: frozenset[str] = field(default=AGENT_ROLES)
+
+
+# --- Contract validation -------------------------------------------------------------
+
+
+def validate_actuator(actuator: Any) -> None:
+    """Checks an actuator against the manifest, raising on any violation.
+
+    Called once from ``get_action_session`` before the first device interaction.
+    """
+    caps = frozenset(actuator.capabilities())
+
+    missing_required = REQUIRED_ACTIONS - caps
+    if missing_required:
+        raise ActuatorContractError(
+            f"{type(actuator).__name__} does not implement required action(s): "
+            f"{sorted(missing_required)}. These are structurally depended on by prompts "
+            f"and cannot be assembled away."
+        )
+
+    missing_internal = INTERNAL_ACTIONS - caps
+    if missing_internal:
+        raise ActuatorContractError(
+            f"{type(actuator).__name__} does not implement internal action(s): "
+            f"{sorted(missing_internal)}. The client-side adapter cannot observe the "
+            f"device without them."
+        )
+
+    unknown = caps - DEVICE_ACTIONS
+    if unknown:
+        raise ActuatorContractError(
+            f"{type(actuator).__name__} claims capabilities unknown to the manifest: "
+            f"{sorted(unknown)}. Backend-specific tools belong in extensions(), not "
+            f"capabilities()."
+        )
+
+    _validate_extensions(actuator)
+
+
+def _validate_extensions(actuator: Any) -> None:
+    """Validates extension tools for name collisions and self-sufficient descriptions."""
+    extensions = list(actuator.extensions())
+    seen: set[str] = set()
+
+    for ext in extensions:
+        if ext.name in ALL_KNOWN_TOOLS:
+            raise ActuatorContractError(
+                f"Extension tool '{ext.name}' collides with a manifest tool of the same "
+                f"name. Extension names must be unique across the whole tool surface."
+            )
+        if ext.name in seen:
+            raise ActuatorContractError(
+                f"{type(actuator).__name__} registers extension '{ext.name}' more than once."
+            )
+        seen.add(ext.name)
+
+        unknown_targets = frozenset(ext.targets) - AGENT_ROLES
+        if unknown_targets:
+            raise ActuatorContractError(
+                f"Extension tool '{ext.name}' targets unknown agent role(s): "
+                f"{sorted(unknown_targets)}. Valid roles: {sorted(AGENT_ROLES)}."
+            )
+
+        if len(ext.description.strip()) < MIN_EXTENSION_DESCRIPTION_LENGTH:
+            raise ActuatorContractError(
+                f"Extension tool '{ext.name}' has a description of "
+                f"{len(ext.description.strip())} characters. Extensions receive no "
+                f"prompt-level guidance, so the description must state when to use the "
+                f"tool and what it does (minimum "
+                f"{MIN_EXTENSION_DESCRIPTION_LENGTH} characters)."
+            )
+
+
+# --- Surface derivation --------------------------------------------------------------
+
+
+def available_device_actions(actuator: Any) -> frozenset[str]:
+    """Returns the LLM-facing device actions this actuator supports.
+
+    Internal actions are excluded: they are adapter plumbing and never reach a model.
+    """
+    caps = frozenset(actuator.capabilities())
+    return (REQUIRED_ACTIONS | OPTIONAL_ACTIONS) & caps
+
+
+def filter_declarations(
+    declarations: list[Any],
+    actuator: Any,
+    agent: str,
+) -> list[Any]:
+    """Filters a declaration list down to what ``actuator`` actually provides.
+
+    Declarations for known tools keep coming from the hand-tuned ``ToolDeclaration``
+    constants -- this layer only removes entries, it never rewrites descriptions.
+    Extension declarations are appended from the actuator itself, since the manifest
+    cannot know them in advance.
+
+    Args:
+        declarations: Declarations the agent would use if every tool existed.
+        actuator: The installed backend.
+        agent: One of :data:`AGENT_ROLES`; selects which extensions apply.
+
+    Returns:
+        Declarations in their original order, with unavailable device actions dropped
+        and this agent's extension tools appended.
+    """
+    if agent not in AGENT_ROLES:
+        raise ValueError(f"Unknown agent role '{agent}'. Valid roles: {sorted(AGENT_ROLES)}.")
+
+    available = available_device_actions(actuator)
+
+    kept = [
+        decl
+        for decl in declarations
+        # Only device actions are gated. Backend-independent tools and anything the
+        # manifest does not classify (e.g. an agent's own bespoke tool) pass through.
+        if _declaration_name(decl) not in DEVICE_ACTIONS
+        or _declaration_name(decl) in available
+    ]
+
+    for ext in actuator.extensions():
+        if agent in ext.targets:
+            kept.append(_extension_declaration(ext))
+
+    return kept
+
+
+def _declaration_name(declaration: Any) -> str:
+    """Reads a tool name off either a ToolDeclaration mapping or a LangChain tool."""
+    name = getattr(declaration, "name", None)
+    if name is None and isinstance(declaration, dict):
+        name = declaration.get("name")
+    return name or ""
+
+
+def _extension_declaration(ext: ExtensionTool) -> Any:
+    """Renders an ExtensionTool into the same ToolDeclaration shape as known tools."""
+    from artemis.core.tool_declaration import ToolDeclaration
+
+    return ToolDeclaration(
+        name=ext.name,
+        description=ext.description,
+        parameters=ext.input_schema,
+    )

artemis/mcp/action_names.py

@@ -0,0 +1,172 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""The one place where the historical verb split is resolved.
+
+Canonical tool names are the agent-facing ones (``click``, ``long_press``,
+``input_text``, ``manage_app``, ...) because those are what the prompts teach and the
+prompts are the contract. The Operator/Validator-internal vocabulary
+(``tap``, ``long_press_on``, ``focus_and_input_text``, ``launch_app``/``stop_app``,
+``back``) is translated here and nowhere else.
+
+``to_canonical_call`` converts a Validator action item (the dicts Operator writes into
+``state.structured_decisions``) into a canonical ``(name, kwargs)`` pair for the
+actuator/session layer, using the ``normalized_coordinates`` the Operator already
+computed so the canonical surface never needs a pixel escape hatch.
+"""
+
+from typing import Any
+
+__all__ = ["OPERATOR_ACTION_TO_CANONICAL", "to_canonical_call"]
+
+#: Operator-internal action verb -> canonical tool name.
+OPERATOR_ACTION_TO_CANONICAL: dict[str, str] = {
+    "tap": "click",
+    "long_press_on": "long_press",
+    "swipe": "swipe",
+    "focus_and_input_text": "input_text",
+    "focus_and_clear_text": "focus_and_clear_text",
+    "erase_one_char": "erase_one_char",
+    "press_key": "press_key",
+    "back": "press_key",
+    "launch_app": "manage_app",
+    "stop_app": "manage_app",
+    "open_link": "open_link",
+    "wait_for_delay": "wait_for_delay",
+}
+
+
+def _norm_pair(
+    action_item: dict[str, Any], dims: tuple[int, int] | None = None
+) -> tuple[int, int] | None:
+    """Reads the Operator-computed normalized [nx, ny] off an action item.
+
+    Falls back to converting the pixel ``coordinates`` when the item predates the
+    ``normalized_coordinates`` field and screen ``dims`` are provided.
+    """
+    coords = action_item.get("normalized_coordinates")
+    if isinstance(coords, (list, tuple)) and len(coords) >= 2:
+        return int(coords[0]), int(coords[1])
+
+    pixel = action_item.get("coordinates")
+    if dims and isinstance(pixel, (list, tuple)) and len(pixel) >= 2:
+        width, height = dims
+        nx = int(max(0, min(1000, round(int(pixel[0]) * 1000 / max(1, width)))))
+        ny = int(max(0, min(1000, round(int(pixel[1]) * 1000 / max(1, height)))))
+        return nx, ny
+    return None
+
+
+def to_canonical_call(
+    action_item: dict[str, Any], dims: tuple[int, int] | None = None
+) -> tuple[str, dict[str, Any]]:
+    """Translates a Validator action item into a canonical (tool, kwargs) call.
+
+    Args:
+        action_item: One entry of the Operator's structured decisions.
+        dims: Optional (width, height) for pixel->normalized fallback on legacy items
+            lacking ``normalized_coordinates``.
+
+    Raises:
+        ValueError: for an unknown action verb or an item missing the coordinates the
+            canonical call requires.
+    """
+    verb = str(action_item.get("action", ""))
+    canonical = OPERATOR_ACTION_TO_CANONICAL.get(verb)
+    if canonical is None:
+        raise ValueError(f"Unsupported action: {verb}")
+
+    if verb == "tap":
+        pair = _norm_pair(action_item, dims)
+        if pair is None:
+            raise ValueError("Invalid coords")
+        return "click", {
+            "target": [pair[0], pair[1]],
+            "times": action_item.get("times") or action_item.get("click_times") or 1,
+            "delay_ms": action_item.get("delay_ms") or action_item.get("delay") or 100,
+        }
+
+    if verb == "long_press_on":
+        pair = _norm_pair(action_item, dims)
+        if pair is None:
+            raise ValueError("Invalid coords")
+        return "long_press", {
+            "target": [pair[0], pair[1]],
+            "duration_ms": action_item.get("duration", 1000),
+        }
+
+    if verb == "swipe":
+        coords = action_item.get("normalized_coordinates")
+        if not (isinstance(coords, (list, tuple)) and len(coords) == 4):
+            pixel = action_item.get("coordinates")
+            if dims and isinstance(pixel, (list, tuple)) and len(pixel) == 4:
+                width, height = dims
+                coords = [
+                    int(max(0, min(1000, round(int(pixel[0]) * 1000 / max(1, width))))),
+                    int(max(0, min(1000, round(int(pixel[1]) * 1000 / max(1, height))))),
+                    int(max(0, min(1000, round(int(pixel[2]) * 1000 / max(1, width))))),
+                    int(max(0, min(1000, round(int(pixel[3]) * 1000 / max(1, height))))),
+                ]
+            else:
+                raise ValueError("Invalid coords")
+        return "swipe", {
+            "start": [int(coords[0]), int(coords[1])],
+            "end": [int(coords[2]), int(coords[3])],
+            "duration_ms": action_item.get("duration", 400),
+        }
+
+    if verb == "focus_and_input_text":
+        pair = _norm_pair(action_item, dims)
+        if pair is None:
+            raise ValueError("Invalid coords")
+        return "input_text", {
+            "text": action_item.get("text", ""),
+            "target": [pair[0], pair[1]],
+            "clear_exist": bool(action_item.get("clear_before_input", False)),
+        }
+
+    if verb == "focus_and_clear_text":
+        pair = _norm_pair(action_item, dims)
+        if pair is None:
+            raise ValueError("Invalid coords")
+        return "focus_and_clear_text", {"target": [pair[0], pair[1]]}
+
+    if verb == "erase_one_char":
+        return "erase_one_char", {}
+
+    if verb == "press_key":
+        keycode = str(action_item.get("keycode", ""))
+        # Operator emits Android-style KEYCODE_* names; the canonical tool takes the
+        # bare key word for the common keys. Anything else keeps its original spelling
+        # so the driver can forward it verbatim (arbitrary KEYCODE_* / numeric codes).
+        bare = keycode.removeprefix("KEYCODE_").lower() if keycode else ""
+        known = {"home", "back", "enter", "delete", "tab", "search", "menu", "app_switch"}
+        return "press_key", {"key": bare if bare in known else keycode}
+
+    if verb == "back":
+        return "press_key", {"key": "back"}
+
+    if verb in ("launch_app", "stop_app"):
+        return "manage_app", {
+            "action": "launch" if verb == "launch_app" else "stop",
+            "app_name": action_item.get("app_name", ""),
+        }
+
+    if verb == "open_link":
+        return "open_link", {"url": action_item.get("url", "")}
+
+    if verb == "wait_for_delay":
+        return "wait_for_delay", {"time_in_ms": action_item.get("time_in_ms", 0)}
+
+    raise ValueError(f"Unsupported action: {verb}")

artemis/mcp/action_server.py

@@ -0,0 +1,353 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""The unified device action MCP server.
+
+``build_action_server`` turns an actuator into a ``FastMCP`` server that registers
+**only** the tools the actuator implements, plus its extension tools -- so
+``list_tools()`` is clean by construction and an absent optional tool is invisible to
+every consumer.
+
+Return protocol: every device action returns a ``CallToolResult`` whose
+``structuredContent`` is an ``ActionResult`` -- ``ok``/``code`` carry the real status
+(killing the historical ``"Error" in text`` sniffing) while ``content`` keeps the
+historical human-readable message. ``isError`` is reserved for protocol-level
+failures; a device refusing an action is ``isError=False, ok=False`` so it reaches the
+model as an observation, not an exception.
+
+Exceptions raised by the actuator are wrapped here with the historical
+``"Error during X: {e}"`` wording the agents' transcripts already contain.
+"""
+
+import asyncio
+from typing import Annotated, Any
+
+from mcp.server.fastmcp import FastMCP
+from mcp.types import CallToolResult, ImageContent, TextContent
+
+from artemis.mcp.action_manifest import validate_actuator
+from artemis.mcp.action_types import ActionCode, ActionResult, ObserveResult
+from artemis.mcp.actuators.base import Actuator
+from artemis.mcp.observation import observe as observe_impl
+from artemis.utils.logger import get_logger
+
+logger = get_logger(__name__)
+
+__all__ = ["build_action_server"]
+
+# Exception wrapping per tool; wording matches the historical executor `except` arms.
+_EXCEPTION_PREFIX = {
+    "click": "Error during click",
+    "click_sequence": "Error executing click sequence",
+    "long_press": "Error during long press",
+    "input_text": "Error during input text",
+    "swipe": "Error during swipe",
+    "press_key": "Error during press_key",
+    "manage_app": "Error during manage_app",
+    "wait_for_delay": "Error during wait_for_delay",
+    "wait_for_text": "Error during wait_for_text",
+}
+
+
+def _wrap(res: ActionResult) -> CallToolResult:
+    return CallToolResult(
+        content=[TextContent(type="text", text=res.message)],
+        structuredContent=res.model_dump(mode="json"),
+        isError=False,
+    )
+
+
+def _wrap_exception(action: str, exc: Exception) -> CallToolResult:
+    prefix = _EXCEPTION_PREFIX.get(action, f"Error during {action}")
+    return _wrap(
+        ActionResult.failure(action, f"{prefix}: {exc}", detail=repr(exc))
+    )
+
+
+def build_action_server(actuator: Actuator, name: str = "artemis_actions") -> FastMCP:
+    """Builds a FastMCP server exposing exactly what ``actuator`` implements.
+
+    Raises ``ActuatorContractError`` when the actuator violates the manifest, so a
+    misconfigured backend fails before serving anything.
+    """
+    validate_actuator(actuator)
+    caps = actuator.capabilities()
+    mcp = FastMCP(name)
+
+    # --- Device actions (registered only when implemented) ---------------------------
+
+    if "click" in caps:
+
+        @mcp.tool()
+        async def click(
+            target: list[int], times: int = 1, delay_ms: int = 100
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Tap at a 0-1000 normalized [x, y] coordinate."""
+            try:
+                return _wrap(
+                    await actuator.click(
+                        int(target[0]), int(target[1]), times=times, delay_ms=delay_ms
+                    )
+                )
+            except Exception as e:
+                return _wrap_exception("click", e)
+
+    if "click_sequence" in caps:
+
+        @mcp.tool()
+        async def click_sequence(
+            sequence: list[list[int]], delay_ms: int = 50
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Tap a series of 0-1000 normalized [x, y] points in one atomic burst."""
+            try:
+                points = [(int(p[0]), int(p[1])) for p in sequence]
+                return _wrap(await actuator.click_sequence(points, delay_ms=delay_ms))
+            except Exception as e:
+                return _wrap_exception("click_sequence", e)
+
+    if "long_press" in caps:
+
+        @mcp.tool()
+        async def long_press(
+            target: list[int], duration_ms: int = 1000
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Long-press at a 0-1000 normalized [x, y] coordinate."""
+            try:
+                return _wrap(
+                    await actuator.long_press(
+                        int(target[0]), int(target[1]), duration_ms=duration_ms
+                    )
+                )
+            except Exception as e:
+                return _wrap_exception("long_press", e)
+
+    if "input_text" in caps:
+
+        @mcp.tool()
+        async def input_text(
+            text: str,
+            target: list[int] | None = None,
+            clear_exist: bool = True,
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Type text, optionally focusing a 0-1000 normalized [x, y] target first."""
+            try:
+                norm = (int(target[0]), int(target[1])) if target else None
+                return _wrap(
+                    await actuator.input_text(text, norm, clear_exist=clear_exist)
+                )
+            except Exception as e:
+                return _wrap_exception("input_text", e)
+
+    if "swipe" in caps:
+
+        @mcp.tool()
+        async def swipe(
+            start: list[int], end: list[int], duration_ms: int = 800
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Swipe between two 0-1000 normalized [x, y] points."""
+            try:
+                return _wrap(
+                    await actuator.swipe(
+                        (int(start[0]), int(start[1])),
+                        (int(end[0]), int(end[1])),
+                        duration_ms,
+                    )
+                )
+            except Exception as e:
+                return _wrap_exception("swipe", e)
+
+    if "press_key" in caps:
+
+        @mcp.tool()
+        async def press_key(key: str) -> Annotated[CallToolResult, ActionResult]:
+            """Press a device key (home, back, enter, delete, tab, search, menu, app_switch)."""
+            try:
+                return _wrap(await actuator.press_key(key))
+            except Exception as e:
+                return _wrap_exception("press_key", e)
+
+    if "manage_app" in caps:
+
+        @mcp.tool()
+        async def manage_app(
+            action: str, app_name: str
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Launch or stop an app by human-readable name or package."""
+            try:
+                return _wrap(await actuator.manage_app(action, app_name))
+            except Exception as e:
+                return _wrap_exception("manage_app", e)
+
+    if "wait_for_delay" in caps:
+
+        @mcp.tool()
+        async def wait_for_delay(
+            time_in_ms: int,
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Wait for a fixed number of milliseconds."""
+            try:
+                return _wrap(await actuator.wait_for_delay(time_in_ms))
+            except Exception as e:
+                return _wrap_exception("wait_for_delay", e)
+
+    if "wait_for_text" in caps:
+
+        @mcp.tool()
+        async def wait_for_text(
+            text: str, wait_state: str = "appear", timeout_ms: int = 5000
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Wait for text to appear on or disappear from the screen."""
+            try:
+                return _wrap(await actuator.wait_for_text(text, wait_state, timeout_ms))
+            except Exception as e:
+                return _wrap_exception("wait_for_text", e)
+
+    if "open_link" in caps:
+
+        @mcp.tool()
+        async def open_link(url: str) -> Annotated[CallToolResult, ActionResult]:
+            """Open a URL on the device."""
+            try:
+                return _wrap(await actuator.open_link(url))
+            except Exception as e:
+                return _wrap_exception("open_link", e)
+
+    if "erase_one_char" in caps:
+
+        @mcp.tool()
+        async def erase_one_char() -> Annotated[CallToolResult, ActionResult]:
+            """Erase a single character in the focused field."""
+            try:
+                return _wrap(await actuator.erase_one_char())
+            except Exception as e:
+                return _wrap_exception("erase_one_char", e)
+
+    if "focus_and_clear_text" in caps:
+
+        @mcp.tool()
+        async def focus_and_clear_text(
+            target: list[int],
+        ) -> Annotated[CallToolResult, ActionResult]:
+            """Focus the field at a 0-1000 normalized [x, y] and clear its text."""
+            try:
+                return _wrap(
+                    await actuator.focus_and_clear_text(int(target[0]), int(target[1]))
+                )
+            except Exception as e:
+                return _wrap_exception("focus_and_clear_text", e)
+
+    # --- Internal observation tools (never declared to an LLM) -----------------------
+
+    if "observe_screen" in caps:
+
+        @mcp.tool()
+        async def observe_screen(
+            settle_ms: int = 400, include_image: bool = False
+        ) -> Annotated[CallToolResult, ObserveResult]:
+            """Capture and index the current screen (adapter-internal)."""
+            try:
+                obs, img_bytes = await observe_impl(
+                    getattr(actuator, "ctx", None),
+                    actuator.controller,
+                    settle_ms=settle_ms,
+                )
+                content: list[Any] = [TextContent(type="text", text=obs.message)]
+                if include_image and img_bytes:
+                    import base64 as _b64
+
+                    content.append(
+                        ImageContent(
+                            type="image",
+                            data=_b64.b64encode(img_bytes).decode("utf-8"),
+                            mimeType="image/jpeg",
+                        )
+                    )
+                return CallToolResult(
+                    content=content,
+                    structuredContent=obs.model_dump(mode="json"),
+                    isError=False,
+                )
+            except Exception as e:
+                obs = ObserveResult(
+                    ok=False,
+                    code=ActionCode.DEVICE_ERROR,
+                    message=f"Error during observe_screen: {e}",
+                    hierarchy_ok=False,
+                )
+                return CallToolResult(
+                    content=[TextContent(type="text", text=obs.message)],
+                    structuredContent=obs.model_dump(mode="json"),
+                    isError=False,
+                )
+
+    # Timeouts on the two observation tools run INSIDE the tool, around the actuator
+    # call only. They must never be expressed as a transport-level read timeout
+    # (``read_timeout_seconds``) or a caller-side ``asyncio.wait_for``: both produce a
+    # late response to an abandoned request, which crashes the mcp-1.29 client
+    # receive loop (``_handle_response`` sends into the request's already-closed
+    # response stream) and bricks the in-memory session for every later caller.
+    # A server-side timeout yields a normal error payload and no late response.
+
+    if "take_screenshot" in caps:
+
+        @mcp.tool()
+        async def take_screenshot(timeout_ms: int | None = None) -> CallToolResult:
+            """Return the current screen as base64 (adapter-internal, no persistence)."""
+            try:
+                coro = actuator.take_screenshot()
+                if timeout_ms:
+                    coro = asyncio.wait_for(coro, timeout=timeout_ms / 1000.0)
+                b64 = await coro
+                payload: dict[str, Any] = {"ok": True, "image_b64": b64}
+            except (TimeoutError, asyncio.TimeoutError):
+                payload = {"ok": False, "error": f"screenshot timed out after {timeout_ms}ms"}
+            except Exception as e:
+                payload = {"ok": False, "error": str(e)}
+            return CallToolResult(
+                content=[TextContent(type="text", text="screenshot" if payload["ok"] else str(payload))],
+                structuredContent=payload,
+                isError=False,
+            )
+
+    if "get_ui_hierarchy" in caps:
+
+        @mcp.tool()
+        async def get_ui_hierarchy(timeout_ms: int | None = None) -> CallToolResult:
+            """Return the raw UI element hierarchy (adapter-internal)."""
+            try:
+                coro = actuator.get_ui_elements()
+                if timeout_ms:
+                    coro = asyncio.wait_for(coro, timeout=timeout_ms / 1000.0)
+                elements = await coro
+                payload: dict[str, Any] = {"ok": True, "elements": elements}
+            except (TimeoutError, asyncio.TimeoutError):
+                payload = {"ok": False, "error": f"ui hierarchy fetch timed out after {timeout_ms}ms"}
+            except Exception as e:
+                payload = {"ok": False, "error": str(e)}
+            return CallToolResult(
+                content=[TextContent(type="text", text="ui_hierarchy" if payload["ok"] else str(payload))],
+                structuredContent=payload,
+                isError=False,
+            )
+
+    # --- Backend extension tools -----------------------------------------------------
+
+    for ext in actuator.extensions():
+        mcp.add_tool(ext.handler, name=ext.name, description=ext.description)
+
+    logger.info(
+        f"Action server '{name}' built with {len(caps)} device actions and"
+        f" {len(actuator.extensions())} extension tools."
+    )
+    return mcp

artemis/mcp/action_session.py

@@ -0,0 +1,249 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""In-process MCP session over the unified action server.
+
+The in-memory transport (``create_connected_server_and_client_session``) wraps the
+server in an ``anyio`` task group whose cancel scope must be entered and exited **in
+the same task**. ``ActionSession`` therefore runs the whole context manager inside one
+owner task and communicates through events: ``call()`` and ``aclose()`` are safe from
+any task, which is what lets the session be created lazily inside an agent node and
+torn down from ``ArtemisContext.__aexit__``.
+
+Transport operations additionally run **only in the owner task**, via a request
+queue: callers enqueue ``(future, name, args, timeout)`` and await the future. A
+caller that times out or is cancelled only abandons its future -- the underlying
+``call_tool`` is never cancelled mid-flight. This matters because cancelling
+``call_tool`` on the in-memory transport corrupts the shared memory streams and
+bricks the session for every subsequent caller (observed live: one 1-second
+``asyncio.wait_for`` around a slow hierarchy fetch killed a 24-minute run, with
+every later call failing on an empty-message ``BrokenResourceError``).
+
+MCP's native ``read_timeout_seconds`` is just as fatal here (also observed live):
+mcp 1.29's ``_handle_response`` delivers a LATE response into the timed-out
+request's already-closed response stream, which crashes the client receive loop.
+Per-call timeouts therefore travel as a ``timeout_ms`` tool argument and fire
+inside the server tool, around the actuator call only -- a timed-out operation
+produces a normal error payload and never a late response.
+
+If the transport does die despite all this, the owner loop exits, which flips
+``started`` to False so the next ``get_action_session`` builds a fresh session
+instead of leaving the rest of the run to fail on a corpse.
+
+The single owner loop also serializes calls, which enforces ARTEMIS's
+single-device policy at the one choke point all agents share -- in particular it
+stops a nested Validator -> FailureAnalyzer flow from interleaving two device
+actions.
+"""
+
+import asyncio
+from typing import Any
+
+import anyio
+from mcp.shared.memory import create_connected_server_and_client_session
+
+from artemis.mcp.action_types import ActionResult, ObserveResult
+from artemis.utils.logger import get_logger
+
+logger = get_logger(__name__)
+
+__all__ = ["ActionSession", "get_action_session"]
+
+_SHUTDOWN = object()  # queue sentinel
+
+
+class ActionSession:
+    """Owns the in-memory MCP client/server pair for one device run."""
+
+    def __init__(self, server: Any):
+        self._server = server
+        self._session: Any = None
+        self._ready = asyncio.Event()
+        self._owner: asyncio.Task | None = None
+        self._error: BaseException | None = None
+        self._requests: asyncio.Queue = asyncio.Queue()
+
+    async def _run(self) -> None:
+        try:
+            # Enter and exit strictly within this task (anyio cancel-scope rule).
+            async with create_connected_server_and_client_session(self._server) as session:
+                self._session = session
+                self._ready.set()
+                await self._serve(session)
+        except BaseException as e:
+            self._error = e
+            self._ready.set()
+            raise
+        finally:
+            self._session = None
+            self._fail_pending("ActionSession owner task has exited.")
+
+    async def _serve(self, session: Any) -> None:
+        """Executes queued transport calls until the shutdown sentinel arrives."""
+        while True:
+            item = await self._requests.get()
+            if item is _SHUTDOWN:
+                return
+            fut, name, args = item
+            if fut.cancelled():
+                continue  # caller gave up before we started; nothing was sent
+            try:
+                result = await session.call_tool(name, args)
+            except BaseException as e:
+                if not fut.cancelled():
+                    fut.set_exception(e)
+                if isinstance(e, asyncio.CancelledError):
+                    raise
+                if isinstance(e, (anyio.ClosedResourceError, anyio.BrokenResourceError)):
+                    # The transport is dead; no future call on this session can
+                    # succeed. Exit so `started` flips False and the next
+                    # get_action_session() builds a fresh session.
+                    logger.error(
+                        "Action session transport failed (%r); retiring this session.", e
+                    )
+                    return
+            else:
+                if not fut.cancelled():
+                    fut.set_result(result)
+
+    def _fail_pending(self, reason: str) -> None:
+        while not self._requests.empty():
+            item = self._requests.get_nowait()
+            if item is _SHUTDOWN:
+                continue
+            fut = item[0]
+            if not fut.done():
+                fut.set_exception(RuntimeError(reason))
+
+    async def start(self) -> "ActionSession":
+        if self._owner is not None:
+            return self
+        self._owner = asyncio.create_task(self._run(), name="artemis-action-session")
+        await self._ready.wait()
+        if self._error is not None:
+            error = self._error
+            self._owner = None
+            self._error = None
+            raise RuntimeError(f"Failed to start action session: {error}") from error
+        return self
+
+    @property
+    def started(self) -> bool:
+        return self._session is not None
+
+    async def call_raw(self, name: str, args: dict[str, Any]) -> Any:
+        """Calls a tool and returns the raw ``CallToolResult``.
+
+        There is deliberately no transport-level timeout here (see the module
+        docstring). Tools that support one take a ``timeout_ms`` argument and time
+        out server-side. Wrapping this coroutine in ``asyncio.wait_for`` merely
+        abandons the caller's future -- harmless, because the transport call itself
+        runs in the owner task and cannot be cancelled from here.
+        """
+        if self._session is None:
+            raise RuntimeError("ActionSession is not started.")
+        fut: asyncio.Future = asyncio.get_running_loop().create_future()
+        self._requests.put_nowait((fut, name, args))
+        result = await fut
+        if getattr(result, "isError", False):
+            # Protocol-level failure (unknown tool, schema violation) -- a programming
+            # error, not a device observation.
+            text = ""
+            for block in getattr(result, "content", []) or []:
+                if getattr(block, "type", None) == "text":
+                    text = block.text
+                    break
+            raise RuntimeError(f"MCP tool '{name}' failed: {text}")
+        return result
+
+    async def call(self, name: str, args: dict[str, Any]) -> ActionResult:
+        """Calls a device action tool and returns its typed result."""
+        result = await self.call_raw(name, args)
+        return ActionResult.model_validate(result.structuredContent)
+
+    async def observe(
+        self, settle_ms: int = 400, include_image: bool = False
+    ) -> ObserveResult:
+        """Captures and indexes the current screen via the internal observe tool."""
+        result = await self.call_raw(
+            "observe_screen", {"settle_ms": settle_ms, "include_image": include_image}
+        )
+        return ObserveResult.model_validate(result.structuredContent)
+
+    async def screenshot_b64(self, timeout: float | None = None) -> str:
+        """Returns the current screen as a base64 string (no persistence)."""
+        args = {"timeout_ms": int(timeout * 1000)} if timeout else {}
+        result = await self.call_raw("take_screenshot", args)
+        payload = result.structuredContent or {}
+        # FastMCP wraps plain-dict returns as {"result": ...} only for non-dict types;
+        # dicts pass through.
+        data = payload.get("result", payload)
+        if not data.get("ok"):
+            raise RuntimeError(f"take_screenshot failed: {data.get('error')}")
+        return data["image_b64"]
+
+    async def ui_hierarchy(self, timeout: float | None = None) -> Any:
+        """Returns the raw UI element hierarchy."""
+        args = {"timeout_ms": int(timeout * 1000)} if timeout else {}
+        result = await self.call_raw("get_ui_hierarchy", args)
+        payload = result.structuredContent or {}
+        data = payload.get("result", payload)
+        if not data.get("ok"):
+            raise RuntimeError(f"get_ui_hierarchy failed: {data.get('error')}")
+        return data["elements"]
+
+    async def aclose(self) -> None:
+        """Shuts the session down; safe to call from any task."""
+        if self._owner is None:
+            return
+        self._requests.put_nowait(_SHUTDOWN)
+        try:
+            await asyncio.wait_for(asyncio.shield(self._owner), timeout=5.0)
+        except (TimeoutError, asyncio.CancelledError, Exception) as e:
+            logger.warning(f"Action session owner task did not exit cleanly: {e!r}")
+        finally:
+            self._owner = None
+            self._ready = asyncio.Event()
+
+
+async def get_action_session(ctx: Any, actuator: Any = None) -> ActionSession:
+    """Returns the context's action session, creating and starting it on first use.
+
+    Contract validation happens here (inside ``build_action_server``), so a backend
+    that cannot satisfy the manifest fails before the first device interaction.
+    """
+    existing = getattr(ctx, "action_session", None)
+    if existing is not None and existing.started:
+        return existing
+    if existing is not None:
+        # A dead session still owns a task and memory streams: release them
+        # before the replacement is built.
+        try:
+            await existing.aclose()
+        except Exception:
+            logger.debug("Closing a dead action session failed; replacing it anyway.")
+
+    from artemis.mcp.action_server import build_action_server
+    from artemis.mcp.actuators.adb import AdbActuator
+
+    actuator = actuator or getattr(ctx, "actuator", None) or AdbActuator(ctx)
+    server = build_action_server(actuator)
+    session = ActionSession(server)
+    await session.start()
+    try:
+        ctx.action_session = session
+    except Exception:
+        # Contexts that forbid new attributes (strict mocks) can still use the session.
+        logger.debug("Could not store action session on ctx; proceeding unattached.")
+    return session

artemis/mcp/action_types.py

@@ -0,0 +1,86 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Typed results for the device action layer.
+
+These models replace the ``"Error" in text`` substring sniffing: success is carried by
+``ok``/``code``, while ``message`` remains the human/LLM-facing summary and keeps its
+historical wording. Kept dependency-free (pydantic only) so servers, adapters, and
+tests can all import it cheaply.
+"""
+
+from enum import Enum
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+__all__ = ["ActionCode", "ActionResult", "ObserveResult"]
+
+
+class ActionCode(str, Enum):
+    """Machine-readable outcome classification for a device action."""
+
+    OK = "OK"
+    INVALID_ARGS = "INVALID_ARGS"
+    TARGET_NOT_FOUND = "TARGET_NOT_FOUND"
+    DEVICE_ERROR = "DEVICE_ERROR"
+    PACKAGE_NOT_FOUND = "PACKAGE_NOT_FOUND"
+    TIMEOUT = "TIMEOUT"
+    UNSUPPORTED = "UNSUPPORTED"
+
+
+class ActionResult(BaseModel):
+    """Outcome of one device action, independent of any transport or agent."""
+
+    ok: bool
+    code: ActionCode
+    action: str
+    message: str
+    """Agent-facing summary; wording matches the historical executor outcomes."""
+    detail: str | None = None
+    """Raw driver/controller error for diagnostics; never shown to the LLM."""
+    normalized_coordinates: list[int] | None = None
+    duration_ms: int | None = None
+
+    @classmethod
+    def success(cls, action: str, message: str, **kwargs: Any) -> "ActionResult":
+        return cls(ok=True, code=ActionCode.OK, action=action, message=message, **kwargs)
+
+    @classmethod
+    def failure(
+        cls,
+        action: str,
+        message: str,
+        code: ActionCode = ActionCode.DEVICE_ERROR,
+        **kwargs: Any,
+    ) -> "ActionResult":
+        return cls(ok=False, code=code, action=action, message=message, **kwargs)
+
+
+class ObserveResult(BaseModel):
+    """Post-action observation: persisted screenshot plus the parsed element list."""
+
+    ok: bool
+    code: ActionCode = ActionCode.OK
+    message: str = ""
+    screenshot_path: str | None = None
+    image_name: str | None = None
+    """Stem of ``screenshot_path``; stable key used by trace/replay consumers."""
+    width: int | None = None
+    height: int | None = None
+    elements_text: str | None = None
+    elements: list[dict[str, Any]] = Field(default_factory=list)
+    hierarchy_ok: bool = True
+    """False when the screenshot succeeded but the UI hierarchy parse failed; callers
+    must then keep their previous element index rather than clobbering it."""

artemis/mcp/actuators/__init__.py

@@ -0,0 +1,21 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Actuator backends: pluggable implementations of the device action contract."""
+
+from artemis.mcp.actuators.base import Actuator
+from artemis.mcp.actuators.adb import AdbActuator
+from artemis.mcp.actuators.mock import MockActuator
+
+__all__ = ["Actuator", "AdbActuator", "MockActuator"]

artemis/mcp/actuators/adb.py

@@ -0,0 +1,419 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""ADB-backed actuator: the reference implementation of the actuator contract.
+
+The device-call bodies here were extracted from
+``artemis.agents.validator.tool_declarations.MobileActionExecutor``; the outcome
+message wording is preserved byte-for-byte because agent transcripts, trace payloads,
+and existing tests assert on it.
+
+Error convention: device-level refusals the controller *reports* (an ``error`` field,
+a falsy success flag) come back as ``ActionResult(ok=False)`` with the historical
+message. Unexpected exceptions are allowed to propagate -- the caller (executor or MCP
+server layer) owns the ``"Error during X: {e}"`` wrapping, exactly as the original
+executor's ``try/except`` did.
+"""
+
+import asyncio
+import inspect
+import re
+import time
+from typing import Any
+
+from artemis.context import ArtemisContext
+from artemis.controllers.unified_controller import UnifiedMobileController
+from artemis.mcp.action_manifest import DEVICE_ACTIONS, ExtensionTool
+from artemis.mcp.action_types import ActionCode, ActionResult
+from artemis.utils.logger import get_logger
+
+logger = get_logger(__name__)
+
+__all__ = ["AdbActuator", "find_element_at_coords", "ensure_focus_at_coords"]
+
+
+def find_element_at_coords(elements: list[dict], x: int, y: int) -> dict | None:
+    """Finds the smallest (leaf-most) focusable element containing pixel [x, y].
+
+    Moved from ``artemis.mcp.adb_server`` so both the stdio server and in-process
+    actuator share one implementation.
+    """
+    matching_element = None
+    min_area = float("inf")
+
+    for elem in elements:
+        is_focusable = (
+            elem.get("focusable") == "true"
+            or elem.get("clickable") == "true"
+            or "EditText" in str(elem.get("class", ""))
+        )
+        if not is_focusable:
+            continue
+
+        bounds_str = elem.get("bounds")
+        if bounds_str and isinstance(bounds_str, str):
+            match = re.match(r"\[(\-?\d+),(\-?\d+)\]\[(\-?\d+),(\-?\d+)\]", bounds_str)
+            if match:
+                x1, y1, x2, y2 = map(int, match.groups())
+                if x1 <= x <= x2 and y1 <= y <= y2:
+                    area = (x2 - x1) * (y2 - y1)
+                    if area < min_area:
+                        min_area = area
+                        matching_element = elem
+
+    return matching_element
+
+
+async def ensure_focus_at_coords(controller, x: int, y: int) -> str | None:
+    """Ensures the element at pixel [x, y] is focused, tapping only if needed.
+
+    Returns an error string on failure, ``None`` on success. Moved from
+    ``artemis.mcp.adb_server``.
+    """
+    try:
+        elements = await controller.get_ui_elements()
+        elem = find_element_at_coords(elements, x, y)
+        if elem and elem.get("focused") == "true":
+            logger.info(f"Element under [{x}, {y}] is already focused. Skipping tap.")
+            return None
+    except Exception as e:
+        logger.warning(f"Failed to check focus status: {e}. Falling back to unconditional tap.")
+
+    result = await controller.tap_at(x=x, y=y)
+    if hasattr(result, "error") and result.error:
+        return result.error
+
+    # Wait for the UI to settle and keyboard to pop up after tapping
+    await asyncio.sleep(1.0)
+    return None
+
+
+class AdbActuator:
+    """Drives an Android device through ``UnifiedMobileController`` over ADB."""
+
+    def __init__(
+        self,
+        ctx: ArtemisContext,
+        controller: UnifiedMobileController | None = None,
+    ):
+        self.ctx = ctx
+        self.controller = controller or UnifiedMobileController(ctx)
+
+    # --- Contract --------------------------------------------------------------------
+
+    def capabilities(self) -> frozenset[str]:
+        return DEVICE_ACTIONS
+
+    def extensions(self) -> list[ExtensionTool]:
+        return []
+
+    # --- Coordinate helpers ----------------------------------------------------------
+
+    def _dims(self) -> tuple[int, int]:
+        width = getattr(self.ctx.device, "device_width", 1080) if self.ctx.device else 1080
+        height = getattr(self.ctx.device, "device_height", 2400) if self.ctx.device else 2400
+        return width or 1080, height or 2400
+
+    def _to_px(self, nx: int, ny: int) -> tuple[int, int]:
+        width, height = self._dims()
+        x = int(max(0, min(width - 1, int(nx) * width / 1000)))
+        y = int(max(0, min(height - 1, int(ny) * height / 1000)))
+        return x, y
+
+    # --- Required action -------------------------------------------------------------
+
+    async def click_sequence(
+        self, points: list[tuple[int, int]], delay_ms: int = 50
+    ) -> ActionResult:
+        outcomes = []
+        for i, (nx, ny) in enumerate(points):
+            x, y = self._to_px(nx, ny)
+            result = await self.controller.tap_at(x, y)
+            err = getattr(result, "error", None) if result else None
+            if err:
+                return ActionResult.failure(
+                    "click_sequence",
+                    f"Error executing click at step {i + 1}: {err}",
+                    detail=str(err),
+                )
+            outcomes.append(f"Tapped at [{x}, {y}]")
+            if i < len(points) - 1:
+                await asyncio.sleep(max(0, delay_ms) / 1000.0)
+
+        return ActionResult.success(
+            "click_sequence",
+            f"Sequence clicked successfully: {'; '.join(outcomes)}",
+        )
+
+    # --- Optional actions ------------------------------------------------------------
+
+    async def click(
+        self, nx: int, ny: int, times: int = 1, delay_ms: int = 100
+    ) -> ActionResult:
+        x, y = self._to_px(nx, ny)
+        result = await self.controller.tap_at(x, y, times=times, delay_ms=delay_ms)
+        err = getattr(result, "error", None) if result else None
+        if err is not None:
+            return ActionResult.failure(
+                "click", f"Error executing click: {err}", detail=str(err)
+            )
+        return ActionResult.success(
+            "click",
+            f"Clicked at [{nx}, {ny}] (normalized) successfully.",
+            normalized_coordinates=[int(nx), int(ny)],
+        )
+
+    async def long_press(self, nx: int, ny: int, duration_ms: int = 1000) -> ActionResult:
+        x, y = self._to_px(nx, ny)
+        result = await self.controller.tap_at(
+            x, y, long_press=True, long_press_duration=duration_ms
+        )
+        err = getattr(result, "error", None) if result else None
+        if err is not None:
+            return ActionResult.failure(
+                "long_press", f"Error executing long press: {err}", detail=str(err)
+            )
+        return ActionResult.success(
+            "long_press",
+            f"Long pressed at [{nx}, {ny}] (normalized) for {duration_ms}ms successfully.",
+            normalized_coordinates=[int(nx), int(ny)],
+            duration_ms=duration_ms,
+        )
+
+    async def input_text(
+        self,
+        text: str,
+        target: tuple[int, int] | None = None,
+        clear_exist: bool = True,
+    ) -> ActionResult:
+        coords = None
+        if target:
+            nx, ny = target
+            x, y = self._to_px(nx, ny)
+            coords = [int(nx), int(ny)]
+            err = await ensure_focus_at_coords(self.controller, x, y)
+            if err:
+                return ActionResult.failure(
+                    "input_text",
+                    f"Error focusing element: {err}",
+                    detail=str(err),
+                    normalized_coordinates=coords,
+                )
+        if clear_exist:
+            if hasattr(self.controller, "erase_text") and not await self.controller.erase_text():
+                return ActionResult.failure(
+                    "input_text",
+                    "Failed to clear existing text",
+                    normalized_coordinates=coords,
+                )
+        elif hasattr(self.controller, "press_key"):
+            # KEYCODE_MOVE_END: move cursor to the end for reliable append.
+            await self.controller.press_key("123")
+        if hasattr(self.controller, "type_text") and not await self.controller.type_text(
+            text, clear_existing=False
+        ):
+            return ActionResult.failure(
+                "input_text",
+                f"Failed typing '{text}'.",
+                normalized_coordinates=coords,
+            )
+
+        return ActionResult.success(
+            "input_text",
+            f"Executed typing '{text}'.",
+            normalized_coordinates=coords,
+        )
+
+    async def swipe(
+        self,
+        start: tuple[int, int],
+        end: tuple[int, int],
+        duration_ms: int = 800,
+    ) -> ActionResult:
+        nx1, ny1 = start
+        nx2, ny2 = end
+        px1, py1 = self._to_px(nx1, ny1)
+        px2, py2 = self._to_px(nx2, ny2)
+        err = await self.controller.swipe_coords(px1, py1, px2, py2, duration_ms)
+        if err:
+            return ActionResult.failure("swipe", f"Error dragging: {err}", detail=str(err))
+        return ActionResult.success(
+            "swipe",
+            f"Swipe completed successfully. Swiped from [{nx1}, {ny1}] to [{nx2}, {ny2}].",
+            normalized_coordinates=[int(nx1), int(ny1), int(nx2), int(ny2)],
+            duration_ms=duration_ms,
+        )
+
+    async def press_key(self, key: str) -> ActionResult:
+        key_str = str(key).lower()
+        if not key_str:
+            return ActionResult.failure(
+                "press_key",
+                f"Error executing key press '{key}'.",
+                code=ActionCode.INVALID_ARGS,
+            )
+
+        if key_str == "back" and hasattr(self.controller, "go_back"):
+            await self.controller.go_back()
+        elif key_str == "home" and hasattr(self.controller, "go_home"):
+            await self.controller.go_home()
+        elif key_str == "enter" and hasattr(self.controller, "press_enter"):
+            await self.controller.press_enter()
+        elif hasattr(self.controller, "press_key"):
+            # Pass unrecognized keycodes through verbatim (KEYCODE_* names, numeric
+            # codes): the driver resolves or forwards them, matching the historical
+            # adb_server behavior of accepting any Android key event.
+            res = await self.controller.press_key(key)
+            err = getattr(res, "error", None) if res else None
+            if err:
+                return ActionResult.failure(
+                    "press_key",
+                    f"Error executing key press '{key}': {err}",
+                    detail=str(err),
+                )
+            if not res:
+                return ActionResult.failure(
+                    "press_key", f"Error executing key press '{key}'."
+                )
+
+        return ActionResult.success("press_key", f"Executed key press '{key}'.")
+
+    async def manage_app(self, action: str, app_name: str) -> ActionResult:
+        # Imported lazily: launch_app pulls in tool wrappers that are costly at import.
+        from artemis.tools.mobile.launch_app import find_package
+        from artemis.utils.app_launch_utils import launch_app_with_retries
+
+        res = find_package(self.ctx, app_name, use_fallback=False)
+        pkg = await res if inspect.iscoroutine(res) else res
+        if not pkg:
+            return ActionResult.failure(
+                "manage_app",
+                f"Error finding package for app: {app_name}",
+                code=ActionCode.PACKAGE_NOT_FOUND,
+            )
+        target_pkg = pkg
+
+        if action.lower() == "launch":
+            res_launch = launch_app_with_retries(self.ctx, target_pkg)
+            if inspect.iscoroutine(res_launch):
+                res_launch = await res_launch
+            if isinstance(res_launch, tuple):
+                success, error_msg = res_launch
+            else:
+                success, error_msg = bool(res_launch), ""
+
+            if success:
+                return ActionResult.success(
+                    "manage_app",
+                    f"Launched app '{app_name}' ({target_pkg}) successfully.",
+                )
+            return ActionResult.failure(
+                "manage_app",
+                f"Failed to launch app '{app_name}': {error_msg}",
+                detail=error_msg or None,
+            )
+        elif action.lower() == "stop":
+            if hasattr(self.controller, "terminate_app"):
+                res_term = self.controller.terminate_app(target_pkg)
+                if inspect.iscoroutine(res_term):
+                    await res_term
+            return ActionResult.success(
+                "manage_app", f"Terminated app '{app_name}' successfully."
+            )
+        return ActionResult.failure(
+            "manage_app",
+            f"Invalid manage_app action: {action}",
+            code=ActionCode.INVALID_ARGS,
+        )
+
+    async def wait_for_delay(self, time_in_ms: int) -> ActionResult:
+        delay_s = max(0.0, float(time_in_ms) / 1000.0)
+        await asyncio.sleep(delay_s)
+        return ActionResult.success(
+            "wait_for_delay",
+            f"Waited for {time_in_ms}ms successfully.",
+            duration_ms=int(time_in_ms),
+        )
+
+    async def wait_for_text(
+        self, text: str, wait_state: str | None = None, timeout_ms: int | None = None
+    ) -> ActionResult:
+        timeout_s = (timeout_ms or 5000) / 1000.0
+        start = time.time()
+        found = False
+        target_state = (wait_state or "appear").lower()
+
+        while time.time() - start < timeout_s:
+            tree = await self.controller.get_ui_elements()
+            text_present = text.lower() in str(tree or "").lower()
+            if target_state == "appear" and text_present:
+                found = True
+                break
+            elif target_state == "disappear" and not text_present:
+                found = True
+                break
+            await asyncio.sleep(0.5)
+
+        if found:
+            return ActionResult.success(
+                "wait_for_text",
+                f"Successfully waited for text '{text}' to {target_state}.",
+            )
+        return ActionResult.failure(
+            "wait_for_text",
+            f"Timed out waiting for text '{text}' to {target_state}.",
+            code=ActionCode.TIMEOUT,
+        )
+
+    async def open_link(self, url: str) -> ActionResult:
+        success = await self.controller.open_url(url)
+        if success:
+            return ActionResult.success("open_link", f"Opened link '{url}' successfully.")
+        return ActionResult.failure("open_link", f"Failed to open link '{url}'.")
+
+    async def erase_one_char(self) -> ActionResult:
+        success = await self.controller.erase_text(nb_chars=1)
+        if success:
+            return ActionResult.success("erase_one_char", "Erased one character.")
+        return ActionResult.failure("erase_one_char", "Failed to erase one character.")
+
+    async def focus_and_clear_text(self, nx: int, ny: int) -> ActionResult:
+        x, y = self._to_px(nx, ny)
+        err = await ensure_focus_at_coords(self.controller, x, y)
+        if err:
+            return ActionResult.failure(
+                "focus_and_clear_text",
+                f"Error focusing element: {err}",
+                detail=str(err),
+                normalized_coordinates=[int(nx), int(ny)],
+            )
+        success = await self.controller.erase_text()
+        if success:
+            return ActionResult.success(
+                "focus_and_clear_text",
+                f"Cleared text at [{nx}, {ny}] (normalized) successfully.",
+                normalized_coordinates=[int(nx), int(ny)],
+            )
+        return ActionResult.failure("focus_and_clear_text", "Failed to erase text.")
+
+    # --- Internal observation primitives ---------------------------------------------
+
+    async def take_screenshot(self) -> str:
+        return await self.controller.take_screenshot()
+
+    async def get_ui_elements(self) -> Any:
+        return await self.controller.get_ui_elements()
+
+    async def get_screen_data(self) -> Any:
+        return await self.controller.get_screen_data()

artemis/mcp/actuators/base.py

@@ -0,0 +1,113 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""The actuator protocol: what any backend must look like to drive a device.
+
+An actuator answers exactly one question -- *how to perform a physical action* -- in
+the canonical 0-1000 normalized coordinate space. It knows nothing about LangGraph
+``State``, prompts, agents, screenshots-as-observations, or MCP. Pixel geometry (or a
+robot arm's motion planning) is a private detail behind this boundary.
+
+A backend advertises what it can do through :meth:`Actuator.capabilities` (names from
+``artemis.mcp.action_manifest.DEVICE_ACTIONS``) and may contribute tools nobody
+anticipated through :meth:`Actuator.extensions`. ``validate_actuator`` in the manifest
+enforces the contract at session start.
+
+Methods for actions a backend does not implement should simply not exist (or raise
+``NotImplementedError``); callers consult ``capabilities()`` first.
+"""
+
+from typing import Any, Protocol, runtime_checkable
+
+from artemis.mcp.action_manifest import ExtensionTool
+from artemis.mcp.action_types import ActionResult
+
+__all__ = ["Actuator"]
+
+
+@runtime_checkable
+class Actuator(Protocol):
+    """Protocol every actuator backend implements.
+
+    All coordinates are 0-1000 normalized. Every action coroutine returns an
+    :class:`ActionResult` and must not raise for device-level failures -- those are
+    reported through ``ok=False`` so a failed tap reaches the agent as an observation
+    rather than an exception.
+    """
+
+    def capabilities(self) -> frozenset[str]:
+        """Names from ``DEVICE_ACTIONS`` this backend implements."""
+        ...
+
+    def extensions(self) -> list[ExtensionTool]:
+        """Backend-specific tools unknown to the manifest."""
+        ...
+
+    # --- Required action -------------------------------------------------------------
+
+    async def click_sequence(
+        self, points: list[tuple[int, int]], delay_ms: int = 50
+    ) -> ActionResult: ...
+
+    # --- Optional actions ------------------------------------------------------------
+
+    async def click(
+        self, nx: int, ny: int, times: int = 1, delay_ms: int = 100
+    ) -> ActionResult: ...
+
+    async def long_press(self, nx: int, ny: int, duration_ms: int = 1000) -> ActionResult: ...
+
+    async def input_text(
+        self,
+        text: str,
+        target: tuple[int, int] | None = None,
+        clear_exist: bool = True,
+    ) -> ActionResult: ...
+
+    async def swipe(
+        self,
+        start: tuple[int, int],
+        end: tuple[int, int],
+        duration_ms: int = 800,
+    ) -> ActionResult: ...
+
+    async def press_key(self, key: str) -> ActionResult: ...
+
+    async def manage_app(self, action: str, app_name: str) -> ActionResult: ...
+
+    async def wait_for_delay(self, time_in_ms: int) -> ActionResult: ...
+
+    async def wait_for_text(
+        self, text: str, wait_state: str | None = None, timeout_ms: int | None = None
+    ) -> ActionResult: ...
+
+    async def open_link(self, url: str) -> ActionResult: ...
+
+    async def erase_one_char(self) -> ActionResult: ...
+
+    async def focus_and_clear_text(self, nx: int, ny: int) -> ActionResult: ...
+
+    # --- Internal observation primitives ---------------------------------------------
+
+    async def take_screenshot(self) -> str:
+        """Returns the current screen as a base64-encoded JPEG/PNG string."""
+        ...
+
+    async def get_ui_elements(self) -> Any:
+        """Returns the raw UI hierarchy elements as provided by the device."""
+        ...
+
+    async def get_screen_data(self) -> Any:
+        """Returns combined screen data (screenshot + elements + dimensions)."""
+        ...

artemis/mcp/actuators/mock.py

@@ -0,0 +1,70 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Mock actuator for tests: real actuator code paths over an in-memory device.
+
+Subclasses :class:`AdbActuator` deliberately, so tests exercise the same coordinate
+conversion and controller dispatch as production -- only the driver is in-memory.
+``capabilities``/``extensions`` are overridable to model partial and extended
+backends.
+"""
+
+from artemis.context import ArtemisContext, DeviceContext, DevicePlatform
+from artemis.drivers.mock.mock_driver import MockDeviceDriver
+from artemis.mcp.action_manifest import DEVICE_ACTIONS, ExtensionTool
+from artemis.mcp.actuators.adb import AdbActuator
+from artemis.platform import platform
+
+__all__ = ["MockActuator"]
+
+
+class MockActuator(AdbActuator):
+    """An :class:`AdbActuator` bound to a :class:`MockDeviceDriver`."""
+
+    def __init__(
+        self,
+        width: int = 1080,
+        height: int = 2400,
+        capabilities: frozenset[str] | None = None,
+        extensions: list[ExtensionTool] | None = None,
+    ):
+        driver = MockDeviceDriver(width=width, height=height)
+        ctx = ArtemisContext(
+            trace_id="mock-actuator",
+            device=DeviceContext(
+                host_platform=platform.os_type.name,
+                mobile_platform=DevicePlatform.ANDROID,
+                device_id=driver.device_id,
+                device_width=width,
+                device_height=height,
+            ),
+        )
+        # get_driver(ctx) returns a cached `_active_driver` when present
+        # (artemis/drivers/factory.py), the established test seam.
+        ctx._active_driver = driver
+        super().__init__(ctx)
+        self.driver = driver
+        self._capabilities = capabilities if capabilities is not None else DEVICE_ACTIONS
+        self._extensions = list(extensions or [])
+
+    def capabilities(self) -> frozenset[str]:
+        return self._capabilities
+
+    def extensions(self) -> list[ExtensionTool]:
+        return self._extensions
+
+    @property
+    def action_history(self) -> list[dict]:
+        """The mock driver's recorded actions, for assertions."""
+        return self.driver.action_history

artemis/mcp/adb_server.py

@@ -17,7 +17,6 @@ import json
 import logging
 import os
 from pathlib import Path
-import re
 import sys
 from typing import Any
 
@@ -43,33 +42,46 @@ from artemis.controllers.unified_controller import UnifiedMobileController
 from artemis.platform import platform
 from artemis.utils.app_launch_utils import launch_app_with_retries
 
-# Redirect stdio to prevent logs from breaking MCP JSON-RPC protocol and causing deadlocks.
-try:
-    from artemis.config import settings
-
-    log_path = Path(settings.TRACES_PATH) / "mcp_server.log"
-except Exception:
-    log_path = Path("traces") / "mcp_server.log"
-
-log_path.parent.mkdir(parents=True, exist_ok=True)
-
-for name in ["artemis", __name__]:
-    log_instance = logging.getLogger(name)
-    log_instance.setLevel(logging.DEBUG)
-    log_instance.propagate = False
-    # Remove standard streams handlers
-    log_instance.handlers = [
-        h for h in log_instance.handlers if not isinstance(h, logging.StreamHandler)
-    ]
-    fh = logging.FileHandler(log_path, encoding="utf-8")
-    fh.setFormatter(logging.Formatter("%(asctime)s | %(name)s | %(levelname)s | %(message)s"))
-    log_instance.addHandler(fh)
-
 logger = logging.getLogger(__name__)
-logger.info("MCP Server Python process fully started. Configuring FastMCP service...")
 
-# Avoid concurrent SQLite WAL locks by blocking child processes from connecting to primary DataEngine.
-os.environ["ARTEMIS_IPC_PORT"] = ""
+
+def configure_stdio_mode() -> None:
+    """Applies process-wide settings required when serving MCP over stdio.
+
+    These are destructive to the host process (console logging is removed and the
+    DataEngine IPC port is cleared), so they must only run when this module owns the
+    process -- i.e. from the ``__main__`` block. Importing this module for its tools
+    or for :func:`_get_controller` must leave the caller's logging and environment
+    untouched.
+    """
+    # Redirect stdio to prevent logs from breaking MCP JSON-RPC protocol and causing deadlocks.
+    try:
+        from artemis.config import settings
+
+        log_path = Path(settings.TRACES_PATH) / "mcp_server.log"
+    except Exception:
+        log_path = Path("traces") / "mcp_server.log"
+
+    log_path.parent.mkdir(parents=True, exist_ok=True)
+
+    for name in ["artemis", __name__]:
+        log_instance = logging.getLogger(name)
+        log_instance.setLevel(logging.DEBUG)
+        log_instance.propagate = False
+        # Remove standard streams handlers
+        log_instance.handlers = [
+            h for h in log_instance.handlers if not isinstance(h, logging.StreamHandler)
+        ]
+        fh = logging.FileHandler(log_path, encoding="utf-8")
+        fh.setFormatter(logging.Formatter("%(asctime)s | %(name)s | %(levelname)s | %(message)s"))
+        log_instance.addHandler(fh)
+
+    logger.info("MCP Server Python process fully started. Configuring FastMCP service...")
+
+    # Avoid concurrent SQLite WAL locks by blocking child processes from connecting
+    # to the primary DataEngine.
+    os.environ["ARTEMIS_IPC_PORT"] = ""
+
 
 # Create minimal MCP server
 mcp = FastMCP("Android_ADB_Controller")
@@ -161,52 +173,13 @@ def _get_controller(device_serial: str | None = None):
     return controller
 
 
-def _find_element_at_coords(elements: list[dict], x: int, y: int) -> dict | None:
-    """Finds the smallest (leaf-most) focusable element containing [x, y]."""
-    matching_element = None
-    min_area = float("inf")
-
-    for elem in elements:
-        is_focusable = (
-            elem.get("focusable") == "true"
-            or elem.get("clickable") == "true"
-            or "EditText" in str(elem.get("class", ""))
-        )
-        if not is_focusable:
-            continue
-
-        bounds_str = elem.get("bounds")
-        if bounds_str and isinstance(bounds_str, str):
-            match = re.match(r"\[(\-?\d+),(\-?\d+)\]\[(\-?\d+),(\-?\d+)\]", bounds_str)
-            if match:
-                x1, y1, x2, y2 = map(int, match.groups())
-                if x1 <= x <= x2 and y1 <= y <= y2:
-                    area = (x2 - x1) * (y2 - y1)
-                    if area < min_area:
-                        min_area = area
-                        matching_element = elem
-
-    return matching_element
-
-
-async def _ensure_focus_at_coords(controller, x: int, y: int) -> str | None:
-    """Ensures the element at [x, y] is focused, tapping only if it is not already focused."""
-    try:
-        elements = await controller.get_ui_elements()
-        elem = _find_element_at_coords(elements, x, y)
-        if elem and elem.get("focused") == "true":
-            logger.info(f"Element under [{x}, {y}] is already focused. Skipping tap.")
-            return None
-    except Exception as e:
-        logger.warning(f"Failed to check focus status: {e}. Falling back to unconditional tap.")
-
-    result = await controller.tap_at(x=x, y=y)
-    if hasattr(result, "error") and result.error:
-        return result.error
-
-    # Wait for the UI to settle and keyboard to pop up after tapping
-    await asyncio.sleep(1.0)
-    return None
+# Shared with the in-process actuator layer; this stdio server keeps its legacy
+# pixel-space contract for external MCP clients, but the element/focus logic has a
+# single implementation in artemis.mcp.actuators.adb.
+from artemis.mcp.actuators.adb import (  # noqa: E402  pylint: disable=wrong-import-position
+    ensure_focus_at_coords as _ensure_focus_at_coords,
+    find_element_at_coords as _find_element_at_coords,
+)
 
 
 @mcp.tool()
@@ -480,6 +453,7 @@ async def get_ui_hierarchy(ctx: Context) -> str:
 if __name__ == "__main__":
     from artemis.runtime import shutdown_awake_service, start_awake_service
 
+    configure_stdio_mode()
     start_awake_service()
     try:
         mcp.run(transport="stdio")

artemis/mcp/observation.py

@@ -0,0 +1,133 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Screen observation: capture, fuse, index, and persist -- without LangGraph State.
+
+This is the act-then-observe half that used to be welded into every executor action
+(``capture_screenshot_and_parse_ui``). Split out so that actuation and observation are
+separate calls: the Flash/FailureAnalyzer adapter observes after each action, while the
+Validator -- which runs its own UI-change polling -- simply never calls it.
+"""
+
+import asyncio
+import base64
+import time
+
+from artemis.config import get_temp_dir
+from artemis.context import ArtemisContext
+from artemis.controllers.unified_controller import UnifiedMobileController
+from artemis.mcp.action_types import ActionCode, ObserveResult
+from artemis.utils.logger import get_logger
+from artemis.utils.ocr_xml_fusion import fuse_ocr_with_xml
+from artemis.utils.visualization import format_minimal_list_with_elements
+
+logger = get_logger(__name__)
+
+__all__ = ["observe"]
+
+
+async def observe(
+    ctx: ArtemisContext,
+    controller: UnifiedMobileController,
+    settle_ms: int = 400,
+    ocr_results: list | None = None,
+) -> tuple[ObserveResult, bytes | None]:
+    """Captures and indexes the current screen.
+
+    Returns the structured observation plus the raw screenshot bytes (an in-process
+    convenience; the serialized ``ObserveResult`` carries only the persisted path).
+
+    Mirrors the historical ``capture_screenshot_and_parse_ui`` behavior exactly:
+    a settling delay, screen capture, XML fusion and element indexing, persistence via
+    the data engine with a temp-file fallback -- and the same failure semantics: a
+    failed capture yields ``ok=False``; a failed hierarchy parse still returns the
+    screenshot with ``hierarchy_ok=False``.
+    """
+    try:
+        if settle_ms > 0:
+            logger.info(f"Delaying {settle_ms / 1000:.1f}s before capturing screen state...")
+            await asyncio.sleep(settle_ms / 1000.0)
+        else:
+            logger.info("Retrieving screen data directly (skip settling)...")
+        device_data = await controller.get_screen_data()
+        screenshot_bytes = base64.b64decode(device_data.base64)
+    except Exception as e:
+        logger.error(f"Failed to capture screen state: {e}")
+        return (
+            ObserveResult(
+                ok=False,
+                code=ActionCode.DEVICE_ERROR,
+                message=f"Failed to capture screen state: {e}",
+                hierarchy_ok=False,
+            ),
+            None,
+        )
+
+    xml_hierarchy = None
+    ocr_results = ocr_results or []
+    elements: list[dict] = []
+    hierarchy_ok = True
+    width = height = None
+    try:
+        xml_hierarchy = device_data.elements
+        width = device_data.width or 1080
+        height = device_data.height or 2400
+        if ctx.device:
+            ctx.device.device_width = width
+            ctx.device.device_height = height
+
+        fused_xml = fuse_ocr_with_xml(xml_hierarchy, ocr_results)
+        minimal_list_str, elements, _ = format_minimal_list_with_elements(fused_xml, width, height)
+    except Exception as e:
+        logger.error(f"Failed to fetch or fuse UI hierarchy: {e}")
+        minimal_list_str = "Not available due to hierarchy error."
+        hierarchy_ok = False
+
+    screenshot_path = None
+    if ctx.data_engine:
+        try:
+            image_name = ctx.data_engine.get_or_create_image(
+                screenshot_bytes,
+                ui_tree=xml_hierarchy,
+                ocr_result=ocr_results,
+            )
+            screenshot_path = str(ctx.data_engine.get_image_path(image_name))
+        except Exception as e:
+            logger.error(f"Failed to save image in DataEngine: {e}")
+
+    if not screenshot_path:
+        try:
+            temp_dir = get_temp_dir("screenshots")
+            temp_file = temp_dir / f"screenshot_{int(time.time())}.jpg"
+            temp_file.write_bytes(screenshot_bytes)
+            screenshot_path = str(temp_file)
+        except Exception as e:
+            logger.error(f"Failed to save fallback screenshot: {e}")
+
+    from pathlib import Path
+
+    return (
+        ObserveResult(
+            ok=True,
+            message="Screen observed.",
+            screenshot_path=screenshot_path,
+            image_name=Path(screenshot_path).stem if screenshot_path else None,
+            width=width,
+            height=height,
+            elements_text=minimal_list_str,
+            elements=elements,
+            hierarchy_ok=hierarchy_ok,
+        ),
+        screenshot_bytes,
+    )

mcp_server/background/task_runner.py

@@ -366,7 +366,11 @@ if __name__ == "__main__":
     parser.add_argument("--trace-id", required=True, help="Unique trace identifier")
     parser.add_argument("--task-desc", required=True, help="Description of the task to run")
     parser.add_argument("--model", required=True, help="Model to use ('Flash' or 'Pro')")
-    parser.add_argument("--conversation-id", required=True, help="Active conversation ID")
+    parser.add_argument(
+        "--conversation-id",
+        default="",
+        help="Conversation ID for wakeup notification routing (optional; empty disables routing)",
+    )
     parser.add_argument("--locked-app-package", help="Package name of app to lock execution to")
     parser.add_argument("--app-path", help="Path to local APK to install before running task")
     parser.add_argument("--expected-output-desc", help="Expected output description")

mcp_server/base.py

@@ -35,5 +35,7 @@ mcp = FastMCP(
     ),
 )
 
-# Import tools so they are registered with the mcp instance upon module load
-import mcp_server.tools  # noqa: E402, F401
+# Tool registration is intentionally NOT done here: mcp_server/__init__.py
+# imports mcp_server.tools (which imports this module), so importing this
+# module from anywhere already registers every tool. Importing tools here as
+# well would create a circular import (base -> tools -> base).

mcp_server/server.py

@@ -24,24 +24,49 @@ if PROJECT_ROOT not in sys.path:
     sys.path.insert(0, PROJECT_ROOT)
 
 # Debug logging and stderr tee to capture crashes without breaking MCP stdio JSON-RPC
+_LOG_MAX_BYTES = 5 * 1024 * 1024
+
+
+def _rotate_log(path: str, max_bytes: int = _LOG_MAX_BYTES) -> None:
+    """Rotates the log to <path>.old once it exceeds max_bytes, so long-lived
+    server processes cannot grow the debug logs without bound."""
+    try:
+        if os.path.exists(path) and os.path.getsize(path) > max_bytes:
+            old_path = path + ".old"
+            if os.path.exists(old_path):
+                os.remove(old_path)
+            os.replace(path, old_path)
+    except Exception:
+        pass
+
+
 try:
     _mcp_log_dir = os.path.join(PROJECT_ROOT, "scratch")
     os.makedirs(_mcp_log_dir, exist_ok=True)
 
-    with open(os.path.join(_mcp_log_dir, "mcp_launch_debug.log"), "a", encoding="utf-8") as _f:
+    _launch_log = os.path.join(_mcp_log_dir, "mcp_launch_debug.log")
+    _rotate_log(_launch_log)
+    with open(_launch_log, "a", encoding="utf-8") as _f:
         _f.write(
             f"[{datetime.datetime.now()}] Artemis MCP Server launched! sys.argv: {sys.argv}, CWD: {os.getcwd()}\n"
         )
 
     class StderrTee:
-        def __init__(self, original, log_path):
+        def __init__(self, original, log_path, max_bytes=_LOG_MAX_BYTES):
             self.original = original
+            self.log_path = log_path
+            self.max_bytes = max_bytes
+            _rotate_log(log_path, max_bytes)
             self.log_file = open(log_path, "a", encoding="utf-8")
 
         def write(self, data):
             self.original.write(data)
             self.log_file.write(data)
             self.log_file.flush()
+            if self.log_file.tell() > self.max_bytes:
+                self.log_file.close()
+                _rotate_log(self.log_path, self.max_bytes)
+                self.log_file = open(self.log_path, "a", encoding="utf-8")
 
         def flush(self):
             self.original.flush()

mcp_server/tools/device_state.py

@@ -34,31 +34,20 @@ from artemis.utils.visualization import format_minimal_list_with_elements
 async def mobile_get_device_state(view_type: str, device_serial: str | None = None) -> str:
     """Real-time mobile device state observer (for debugging and validation).
 
-    Use this tool to inspect the latest mobile status or to assist in tracking
-    the subagent's task progress.
-
-    Retrieves a real-time screenshot (returns local file URI) or a simplified
-    element tree text list of the target mobile device.
-
-    ### Device Selection Modes:
-    1. **Direct Device Specification**: Provide `device_serial` to observe a specific
-       phone or emulator (e.g. `device_serial="63191FDKX00062"`).
-    2. **Automatic Device Selection**: Omit `device_serial` or leave it `None` to
-       automatically inspect the default/connected device.
-
-    **Diagnostics & User Preference**:
-    - When multiple devices are attached, prioritize letting the user specify or confirm the device.
-    - Run `adb devices` to check connected devices and identify their serial numbers.
+    Retrieves a real-time screenshot or a simplified UI element tree from the
+    target device — useful for inspecting device status or tracking a
+    subagent's progress.
 
     Args:
-        view_type: The observation type. Supported values:
-          - "screenshot": Captures the real-time mobile screen and saves it to the workspace,
-            returning the local URI path of the image file (e.g., "file:///path/to/screenshot.jpg").
-          - "hierarchy": Directly returns the simplified text-labeled element list, which is
-            identical to what the mobile UI automation subagent sees when making decisions.
-        device_serial: Optional Android device serial number (e.g., "63191FDKX00062" or
-          "emulator-5554"). If specified, inspects state from that specific device. If omitted,
-          inspects the default connected device.
+        view_type: Observation type:
+          - "screenshot": captures the screen, saves it to the workspace, and
+            returns the image's local file URI.
+          - "hierarchy": returns the simplified text-labeled element list —
+            exactly what the automation subagent sees when making decisions.
+        device_serial: Optional device serial (e.g. "emulator-5554") to inspect
+          a specific device; omitted → the default connected device. With
+          several devices attached, confirm the target with the user
+          (`adb devices -l` lists serials).
     """
     try:
         controller = _get_controller(device_serial=device_serial)

mcp_server/tools/inspect_trace.py

@@ -74,54 +74,30 @@ def _draw_action_overlay(bg_image_path: str, action_obj: dict, output_path: str)
 
 @mcp.tool()
 async def mobile_inspect_trace(action: str, trace_id: str, step_number: int | None = None) -> Any:
-    """A specialized trace data retrieval tool designed to extract execution details of mobile automation tasks.
+    """Retrieves execution details of a mobile automation task (running or finished).
 
-    Use this tool DURING a running task or AFTER it has finished (or failed) to
-    monitor progress, verify answers, diagnose agent errors, and debug.
-    It provides comprehensive runtime information (including the assigned
-    `device_serial`), raw agent outputs, and visual screenshots for both
-    **Flash** and **Pro** tasks.
+    Use it to monitor progress, verify answers, and diagnose agent errors for
+    both Flash and Pro tasks. Every result includes the assigned `device_serial`.
 
-    ### Available Actions:
-    - **'view_summary'**: Retrieves a high-level execution summary across all
-    steps, including the target `device_serial`.
-        * **Pro Model**: Displays a hierarchical task plan summary, showing the
-        status, device serial, and descriptions of all completed, active, and pending steps.
-        * **Flash Model**: Displays an all-in-one execution chain containing the
-        complete reasoning (thoughts/motivation), device serial, and action taken (`click`,
-        `input_text`, etc.) for every single step.
-
-    - **'view_step_screenshots'**: Retrieves local file paths of screenshots for
-    a specific step (supports both Flash and Pro), along with `device_serial`. Returns:
-        1. `before_screenshot`: The original device screenshot observed by the
-        agent right before taking the action.
-        2. `after_screenshot`: A post-action screenshot capturing the failure or
-        mismatch state (if the action failed or was intercepted). Note: This is
-        conditional/optional and will be `None` (`null`) for normal/successful
-        steps where no extra post-action screenshot was captured.
-        3. `action_overlay_screenshot`: The `before_screenshot` with the agent's
-        action visually marked (e.g., red circle for taps, red arrow for
-        swipes). CRITICAL for verifying if the agent tapped the correct UI
-        element.
-        4. `device_serial`: The serial of the device on which this step was executed.
-
-    - **'view_step_details'**: Retrieves deep runtime logs, raw VLM thoughts,
-    and exact actions for a specific step, along with `device_serial`.
-        * **Pro Model**: Fully supported. Returns detailed per-step diagnostic
-        data.
-        * **Flash Model**: DO NOT USE. (Flash reasoning and actions are already
-        fully included in 'view_summary', making this action redundant).
+    ### Actions
+    - **'view_summary'**: High-level execution summary across all steps.
+      Pro: hierarchical task plan with per-step status; Flash: full execution
+      chain with each step's reasoning and action.
+    - **'view_step_screenshots'**: Local file paths of one step's screenshots:
+      `before_screenshot` (what the agent saw), `after_screenshot` (only set
+      when the action failed/was intercepted, else null), and
+      `action_overlay_screenshot` (the action visually marked — e.g. red circle
+      for taps — key for verifying the agent tapped the right element).
+    - **'view_step_details'**: Deep per-step diagnostics (raw VLM thoughts,
+      exact actions). Pro only — DO NOT use for Flash tasks ('view_summary'
+      already carries their full execution chain).
 
     Args:
-        action: STR. **REQUIRED**. The retrieval action to perform
-          (`"view_summary"`, `"view_step_screenshots"`, or
-          `"view_step_details"`).
-        trace_id: STR. **REQUIRED**. The unique session identifier of the task
-          (returned by `mobile_run_task`).
-        step_number: INT. **CONDITIONAL**. The 1-indexed step number to query. -
-          You MUST provide this if `action="view_step_screenshots"` or
-          `action="view_step_details"`. - You MUST omit or leave this empty if
-          `action="view_summary"`.
+        action: `"view_summary"`, `"view_step_screenshots"`, or
+          `"view_step_details"`.
+        trace_id: The task's session identifier from `mobile_run_task`.
+        step_number: 1-indexed step to query; required for the two per-step
+          actions, omit for `view_summary`.
     """
     project_root = env_utils.get_project_root()
     db_path = os.path.join(trace_store.TRACES_DIR, "data_engine.db")

mcp_server/tools/task_manager.py

@@ -27,6 +27,161 @@ from mcp_server.notifiers import notify
 from mcp_server.utils import env_utils, trace_store
 from artemis.runtime import DeviceExecutionLock, process_supervisor
 
+_LIVENESS_FAILURE_ERROR = "Task runner process terminated unexpectedly."
+# Grace window covering the spawn race: the launcher pid may already have exited
+# while the real runner has not yet registered its own pid in the DataEngine DB.
+_STARTUP_GRACE_SECONDS = 45.0
+
+
+def _find_data_engine_db() -> str | None:
+    db_path = os.path.join(trace_store.TRACES_DIR, "data_engine.db")
+    if os.path.exists(db_path):
+        return db_path
+    db_path = os.path.join(env_utils.get_project_root(), "traces", "data_engine.db")
+    return db_path if os.path.exists(db_path) else None
+
+
+def _pid_alive(pid: int | None) -> bool:
+    if not pid:
+        return False
+    try:
+        import psutil
+
+        proc = psutil.Process(int(pid))
+        return proc.is_running() and proc.status() != psutil.STATUS_ZOMBIE
+    except Exception:
+        try:
+            os.kill(int(pid), 0)
+            return True
+        except OSError:
+            return False
+
+
+def _session_tracked_by_lock(trace_id: str) -> bool:
+    """True when the device-lock layer still tracks this session (queued or active owner)."""
+    try:
+        for q_item in DeviceExecutionLock.get_queued_tasks():
+            if str(q_item.get("session_id")) == trace_id:
+                return True
+    except Exception:
+        pass
+    try:
+        for owner in DeviceExecutionLock.get_active_owners().values():
+            if owner.session_id and str(owner.session_id) == trace_id:
+                return True
+    except Exception:
+        pass
+    return False
+
+
+def _reconcile_task_state(
+    trace_id: str, status_data: dict[str, Any]
+) -> tuple[str, int | None, bool]:
+    """Reconcile status.json with the DataEngine DB and real process liveness.
+
+    The DB session row is written by the runner process itself (``os.getpid()``),
+    so its pid and terminal status outrank the pid recorded at spawn time -- on
+    Windows that spawn pid is a short-lived venv launcher, not the runner. A dead
+    or missing pid alone never fails a task that the DB, the device-lock queue,
+    or an active lock owner still reports as alive.
+
+    Returns ``(current_status, pid, is_alive)`` and persists any correction back
+    to status.json (including recovering from a previously misreported failure).
+    """
+    current_status = status_data.get("status", "unknown")
+    pid = status_data.get("pid")
+    dirty = False
+
+    db_status: str | None = None
+    db_pid: int | None = None
+    db_path = _find_data_engine_db()
+    if db_path:
+        try:
+            conn = sqlite3.connect(db_path)
+            conn.row_factory = sqlite3.Row
+            row = conn.execute(
+                "SELECT status, pid FROM sessions WHERE session_id = ? ORDER BY start_time DESC LIMIT 1",
+                (trace_id,),
+            ).fetchone()
+            conn.close()
+            if row:
+                db_status = row["status"]
+                db_pid = row["pid"]
+        except Exception:
+            pass
+
+    if db_pid and db_pid != pid:
+        pid = db_pid
+        status_data["pid"] = pid
+        dirty = True
+
+    # The DB terminal verdict only fills in a status.json that has not reached a
+    # terminal state itself, or corrects a liveness-inferred failure. It never
+    # overrides a completed result or an explicit user cancellation.
+    liveness_failed = (
+        current_status == "failed" and status_data.get("error") == _LIVENESS_FAILURE_ERROR
+    )
+    if db_status in ("completed", "success", "failed", "cancelled") and (
+        current_status in ("running", "pending") or liveness_failed
+    ):
+        canonical = "completed" if db_status in ("completed", "success") else db_status
+        if current_status != canonical:
+            current_status = canonical
+            status_data["status"] = canonical
+            if canonical != "failed" and status_data.get("error") == _LIVENESS_FAILURE_ERROR:
+                status_data["error"] = None
+            if not status_data.get("end_time"):
+                status_data["end_time"] = time.time()
+            dirty = True
+        is_alive = False
+    elif current_status in ("running", "pending"):
+        if not pid:
+            # No pid recorded (daemon dispatch never writes one): liveness cannot be
+            # inferred, so the task is assumed alive -- matching the historical
+            # behavior of only checking liveness when a pid exists.
+            is_alive = True
+        else:
+            is_alive = _pid_alive(pid)
+        if not is_alive:
+            if _session_tracked_by_lock(trace_id):
+                # Still queued for a device or owned by a live lock holder.
+                is_alive = True
+            elif db_status in ("running", "pending") and db_pid:
+                # The runner registered itself and its process is gone: truly dead.
+                current_status = "failed"
+                _mark_liveness_failure(trace_id, status_data)
+            elif (time.time() - (status_data.get("start_time") or 0)) < _STARTUP_GRACE_SECONDS:
+                is_alive = True
+            else:
+                current_status = "failed"
+                _mark_liveness_failure(trace_id, status_data)
+    else:
+        is_alive = False
+
+    if dirty:
+        trace_store.write_status(trace_id, status_data)
+    return current_status, pid, is_alive
+
+
+def _mark_liveness_failure(trace_id: str, status_data: dict[str, Any]) -> None:
+    trace_store.update_trace_status(trace_id, "failed", error=_LIVENESS_FAILURE_ERROR)
+    status_data["status"] = "failed"
+    status_data["error"] = _LIVENESS_FAILURE_ERROR
+    conv_id = status_data.get("conversation_id")
+    if conv_id:
+        try:
+            notify(
+                conversation_id=conv_id,
+                message=(
+                    f"Artemis background task died unexpectedly for trace '{trace_id}'. "
+                    f"Error: {_LIVENESS_FAILURE_ERROR}"
+                ),
+                event_type="failed",
+                payload={"trace_id": trace_id, "error": _LIVENESS_FAILURE_ERROR},
+            )
+        except Exception:
+            pass
+
 
 @mcp.tool()
 def mobile_manage_task(
@@ -34,53 +189,31 @@ def mobile_manage_task(
 ) -> dict[str, Any]:
     """Manages the lifecycle and retrieves the status of a background mobile automation task.
 
-    This is your primary diagnostic and control tool. You MUST use this tool to
-    poll the task status
-    when your 1-minute fallback timer triggers (as requested by
-    `mobile_run_task`). You can also use
-    it to gracefully abort a task or forcefully correct the subagent's behavior
-    mid-flight.
+    This is your primary diagnostic and control tool for tasks started by
+    `mobile_run_task`. You MUST use it to poll the task status when your
+    1-minute fallback timer triggers (as required by `mobile_run_task`). You
+    can also steer a subagent that is stuck or off-track, or abort a task.
 
-    ### Available Actions:
-    - **'status'**: Retrieves execution progress, elapsed time, and metadata.
-    Returns a JSON object containing:
-        * `trace_id`: Unique identifier for the task.
-        * `status`: Task lifecycle state ('running', 'completed', 'failed', 'cancelled').
-        * `device_serial`: The Android device serial number assigned to/running this task
-          (essential in multi-device environments to know which phone this task belongs to).
-        * `task_desc`: The goal/description of the task.
-        * `model`: 'Flash' or 'Pro'.
-        * `elapsed_seconds`: Execution duration in seconds.
-        * `progress`: Live progress data (current turn, latest thoughts and actions for Flash;
-          active task plan for Pro).
-        * **How to use the output**:
-            - For **Pro Model**, check `progress.task_plan` to see if the
-            agent's long-term plan aligns with your goal.
-            - For **Flash Model**, monitor `current_turn`, `latest_action`, and
-            `latest_thought`. If the turn count increases rapidly without
-            progressing, or the thought indicates it is stuck, you should
-            intervene.
-
-    - **'inject_instruction'**: Injects real-time guidance when the subagent
-    makes a mistake, gets stuck, or loops.
-        * **Pro Model**: Applied at the start of the next turn's planning phase.
-        * **Flash Model**: Applied at the start of the next reactive execution
-        loop.
-        * *Note*: You MUST provide the `instruction` argument for this action.
-
-    - **'stop'**: Forcefully terminates the subagent (Pro or Flash), immediately
-    halting device interactions and releasing the device. Use this if the task
-    is complete, irreparably broken, or running out of control.
+    ### Actions
+    - **'status'**: Returns `trace_id`, `status` ('running'/'completed'/'failed'/
+      'cancelled'), `device_serial` (which phone owns this task in multi-device
+      setups), `task_desc`, `model`, `elapsed_seconds`, and `progress` (Flash:
+      current turn, latest thought/action — intervene if turns climb without
+      progress or the thought indicates it is stuck; Pro: the active task plan
+      — check it still aligns with your goal).
+    - **'inject_instruction'**: Injects real-time guidance mid-flight when the
+      subagent errs, stalls, or loops. Applied at the start of the next
+      planning turn (Pro) or the next reactive loop (Flash). Requires
+      `instruction`.
+    - **'stop'**: Forcefully terminates the subagent, immediately halting
+      device interactions and releasing the device. Use when the task is done,
+      irreparably broken, or running out of control.
 
     Args:
-        action: STR. **REQUIRED**. The management action to perform. Must be
-          exactly `"status"`, `"stop"`, or `"inject_instruction"`.
-        trace_id: STR. **REQUIRED**. The unique session identifier of the task
-          (returned by `mobile_run_task`).
-        instruction: STR. **CONDITIONAL**. The real-time correction or guidance
-          string. - You MUST provide this if `action="inject_instruction"`. -
-          You MUST leave this empty or omit it if `action="status"` or
-          `action="stop"`.
+        action: `"status"`, `"inject_instruction"`, or `"stop"`.
+        trace_id: The task's session identifier from `mobile_run_task`.
+        instruction: Guidance string; required for `inject_instruction`, omit
+          otherwise.
     """
     status_data = trace_store.read_status(trace_id)
     if not status_data:
@@ -90,62 +223,7 @@ def mobile_manage_task(
             "message": f"Trace ID '{trace_id}' not found.",
         }
 
-    current_status = status_data.get("status", "unknown")
-    pid = status_data.get("pid")
-    is_alive = False
-
-    project_root = env_utils.get_project_root()
-    db_path = os.path.join(trace_store.TRACES_DIR, "data_engine.db")
-    if not os.path.exists(db_path):
-        db_path = os.path.join(project_root, "traces", "data_engine.db")
-
-    # If status is still running or pending, sync from database if available
-    if current_status in ("running", "pending") and os.path.exists(db_path):
-        try:
-            conn_st = sqlite3.connect(db_path)
-            conn_st.row_factory = sqlite3.Row
-            cur_st = conn_st.cursor()
-            cur_st.execute(
-                "SELECT status, pid FROM sessions WHERE session_id = ? ORDER BY start_time DESC LIMIT 1",
-                (trace_id,),
-            )
-            row_st = cur_st.fetchone()
-            if row_st:
-                db_status = row_st["status"]
-                db_pid = row_st["pid"]
-                if db_pid and not pid:
-                    pid = db_pid
-                    status_data["pid"] = pid
-                    trace_store.write_status(trace_id, status_data)
-                if db_status in ("completed", "success", "failed", "cancelled"):
-                    canonical_status = "completed" if db_status in ("completed", "success") else db_status
-                    current_status = canonical_status
-                    status_data["status"] = canonical_status
-                    trace_store.write_status(trace_id, status_data)
-            conn_st.close()
-        except Exception:
-            pass
-
-    if pid and current_status in ("running", "pending"):
-        try:
-            os.kill(pid, 0)
-            is_alive = True
-        except OSError:
-            current_status = "failed"
-            error_text = "Task runner process terminated unexpectedly."
-            trace_store.update_trace_status(trace_id, "failed", error=error_text)
-            conv_id = status_data.get("conversation_id")
-            if conv_id:
-                try:
-                    notify(
-                        conversation_id=conv_id,
-                        message=f"Artemis background task died unexpectedly for trace '{trace_id}'. Error: {error_text}",
-                        event_type="failed",
-                        payload={"trace_id": trace_id, "error": error_text},
-                    )
-                except Exception:
-                    pass
-            status_data = trace_store.read_status(trace_id) or status_data
+    current_status, pid, is_alive = _reconcile_task_state(trace_id, status_data)
 
     trace_dir = trace_store.get_trace_dir(trace_id)
 

mcp_server/tools/task_runner.py

@@ -16,134 +16,222 @@
 
 import os
 import subprocess
+import sys
+import threading
+import time
 from typing import Any
 import uuid
 
 from mcp_server.base import mcp
+from mcp_server.notifiers import notify
 from mcp_server.utils import env_utils, trace_store
 from artemis.runtime import DeviceExecutionLock
 
+# Seconds the spawned runner gets to finish its imports and open its log files
+# before the spawn is declared dead. Normal startup creates stdout.log within a
+# few seconds; a runner that produced no logs by this deadline is hung in
+# interpreter/DLL startup and will never recover (observed on Windows when the
+# MCP server process context degrades).
+SPAWN_WATCHDOG_SECONDS = 60
+
+
+def _kill_process_tree(pid: int) -> None:
+    """Terminate a spawned runner and its children (the venv shim re-execs python)."""
+    if sys.platform == "win32":
+        subprocess.run(
+            ["taskkill", "/PID", str(pid), "/T", "/F"],
+            stdin=subprocess.DEVNULL,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        )
+    else:
+        try:
+            os.kill(pid, 9)
+        except OSError:
+            pass
+
+
+def _watch_spawn(
+    trace_id: str,
+    pid: int,
+    queue_ticket: str,
+    conversation_id: str | None,
+    deadline_seconds: float = SPAWN_WATCHDOG_SECONDS,
+    poll_interval: float = 2.0,
+) -> bool:
+    """Watch a freshly spawned runner; kill and fail the task if it never boots.
+
+    The runner opens stdout.log/stderr.log immediately after module imports, so
+    their absence after the deadline means the process is wedged before running
+    any task code. Without this, a wedged spawn leaves the task in 'running'
+    forever and holds its device-queue ticket.
+
+    Returns True when the runner booted (or was already terminal), False when it
+    was declared hung and killed.
+    """
+    trace_dir = trace_store.get_trace_dir(trace_id)
+    log_paths = (
+        os.path.join(trace_dir, "stdout.log"),
+        os.path.join(trace_dir, "stderr.log"),
+    )
+
+    deadline = time.monotonic() + deadline_seconds
+    while time.monotonic() < deadline:
+        if any(os.path.exists(p) for p in log_paths):
+            return True  # runner booted normally
+        status_data = trace_store.read_status(trace_id)
+        if status_data and status_data.get("status") not in ("running", "pending"):
+            return True  # already terminal (e.g. stopped by the user)
+        time.sleep(poll_interval)
+
+    if any(os.path.exists(p) for p in log_paths):
+        return True
+    status_data = trace_store.read_status(trace_id)
+    if status_data and status_data.get("status") not in ("running", "pending"):
+        return True
+
+    error_text = (
+        f"Background runner (pid {pid}) produced no logs within "
+        f"{deadline_seconds:.0f}s of spawn and was killed: the process hung "
+        "during interpreter startup. Restarting the MCP server usually clears "
+        "this; the task can be resubmitted afterwards."
+    )
+    _kill_process_tree(pid)
+    DeviceExecutionLock.cancel_reservation(queue_ticket)
+    trace_store.update_trace_status(trace_id, "failed", error=error_text)
+    if conversation_id:
+        try:
+            notify(
+                conversation_id=conversation_id,
+                message=f"Artemis task '{trace_id}' failed to start: {error_text}",
+                event_type="failed",
+                payload={"trace_id": trace_id, "error": error_text},
+            )
+        except Exception:
+            pass
+    return False
+
+
+def _start_spawn_watchdog(
+    trace_id: str,
+    pid: int,
+    queue_ticket: str,
+    conversation_id: str | None,
+) -> None:
+    """Run _watch_spawn on a daemon thread so the tool call returns immediately."""
+    threading.Thread(
+        target=_watch_spawn,
+        args=(trace_id, pid, queue_ticket, conversation_id),
+        name=f"spawn-watchdog-{trace_id[:8]}",
+        daemon=True,
+    ).start()
+
+
+def _validate_device_serial(device_serial: str) -> dict[str, Any] | None:
+    """Reject a task whose explicitly requested device is not attached and authorized.
+
+    Returns a failure response dict when the serial must be rejected, or None when
+    the device is usable. If device enumeration itself fails (no adb available),
+    validation is skipped rather than blocking task submission.
+    """
+    try:
+        from artemis.runtime import device_pool
+        from artemis.runtime.device_lock import DeviceExecutionLock
+
+        norm = DeviceExecutionLock._normalize_device_id
+        attached = {norm(d.serial): d.state for d in device_pool.list_devices()}
+    except Exception:
+        return None
+    if not attached:
+        # Enumeration unavailable (no adb / transient failure): let the task
+        # proceed and fail downstream with a clear no-device error instead.
+        return None
+
+    dev_state = attached.get(norm(device_serial))
+    if dev_state == "device":
+        return None
+
+    if dev_state is None:
+        detail = (
+            f"Device '{device_serial}' is not connected. "
+            f"Attached devices: {sorted(attached) if attached else 'none'}."
+        )
+    else:
+        detail = f"Device '{device_serial}' is attached but not ready (state: '{dev_state}')."
+    return {
+        "status": "failed",
+        "error": detail,
+        "message": (
+            f"{detail} Task rejected to prevent execution on an unintended device. "
+            "Run `adb devices -l` to inspect attached hardware, then resubmit with a "
+            "valid serial (or omit device_serial for automatic selection)."
+        ),
+    }
+
 
 @mcp.tool()
 def mobile_run_task(
     task_desc: str,
-    conversation_id: str,
+    conversation_id: str | None = None,
     model: str = "Flash",
     locked_app_package: str | None = None,
     app_path: str | None = None,
     expected_output_desc: str | None = None,
     device_serial: str | None = None,
 ) -> dict[str, Any]:
-    """Starts a specialized mobile UI automation subagent to autonomously plan and execute tasks on a connected Android device.
+    """Starts an autonomous mobile UI automation subagent on a connected Android device.
 
-    With this tool, you can delegate complex mobile workflows and UI
-    interactions to a background agent.
-    This tool supports two execution models: **Flash** (for rapid,
-    straightforward UI scripts) and **Pro** (for complex, exploratory tasks
-    requiring deep reasoning).
+    Delegates a mobile workflow to a background agent. Non-blocking: returns
+    immediately with `trace_id` (for `mobile_manage_task` / `mobile_inspect_trace`),
+    `device_serial`, `stdout_log`/`stderr_log` paths, and `notes_dir` (Pro only).
+    On completion (success or failure) a Reactive Wakeup notifies you — but only
+    when `conversation_id` was provided; without it, rely on your fallback timer.
 
-    ### Device Selection & Multi-Device Support (CRITICAL)
-    ARTEMIS supports multi-device execution and provides two device selection modes:
-    1. **Direct Device Specification**: Specify `device_serial` explicitly
-       (e.g., `device_serial="63191FDKX00062"` or `device_serial="emulator-5554"`).
-       Tasks targeting different devices run concurrently via per-device locking.
-    2. **Automatic Device Selection**: If `device_serial` is omitted or `None`,
-       ARTEMIS will automatically select the connected device or allocate an idle device
-       from the device pool.
+    ### Model selection (routing)
+    - **Flash** (default, preferred): simple, deterministic tasks completable
+      within ~30 UI steps. No log/video analysis, no ADB shell, no persistent
+      plan or notes — unsuitable for exploration, complex error recovery,
+      monitoring/polling, or tasks that must report back large amounts of
+      detail.
+    - **Pro**: complex, exploratory, or multi-branch tasks; continuous
+      monitoring/polling; tasks needing ADB shell, system logs, video analysis,
+      multi-step planning, or detailed written output (via notes and
+      `expected_output_desc`).
 
-    **Device Selection Policy & Diagnostics**:
-    - **Prioritize User Choice**: When multiple devices or emulators are connected (or when
-      user intent is not explicitly specified), **ALWAYS PRIORITIZE ASKING THE USER** to
-      choose or confirm the target device before launching tasks.
-    - **Device Diagnosis with `adb devices`**: Always use `adb devices` (or `adb devices -l`)
-      to inspect connected hardware, verify authorization states (`device` vs `unauthorized`),
-      and retrieve active device serials when diagnosing or before delegating tasks.
+    Timing is not precise: the agent's own inference adds ~5 s per step (Flash)
+    or ~30 s per turn (Pro) on top of any requested waits — account for this
+    when the task involves waiting. For recurring workflows, run once to
+    discover the path, then author a deterministic script instead of
+    re-delegating.
 
-    ### Model Selection Guide (CRITICAL FOR ROUTING)
-    You MUST choose the appropriate `model` based on the task complexity:
-    - **Flash**: Best for simple, deterministic tasks that can be completed
-    within **30 UI steps**. You should prioritize using this model to complete
-    the task.
-      *Limitations*: Flash CANNOT analyze video recordings, query system logs,
-      execute arbitrary ADB shell commands, maintain a structured task plan, or
-      write custom execution notes/reports. Do not use Flash if the task
-      requires exploration, complex error recovery, continuous monitoring/polling
-      (due to step count limits and lack of state persistence), or outputting
-      large amounts of detailed information (as Flash cannot access the
-      notes/scratchpad system to retain extensive details across steps; use
-      **Pro** instead).
-    - **Pro**: Required for complex, non-linear, or exploratory tasks (e.g.,
-    browsing deep lists, troubleshooting app crashes, tasks requiring multi-step
-    planning), continuous monitoring or polling tasks (e.g., periodically checking
-    UI state, polling until specific conditions or events occur, watching progress,
-    or waiting for background changes), OR when you need the subagent to extract,
-    remember, and output large amounts of detailed information. Pro is slower but
-    fully featured.
-      *Capabilities*: Supports full video analysis, system log querying, ADB
-      shell access, robust monitoring/polling execution loops with multi-agent
-      planning, and generating custom text outputs/reports via the expected
-      output agent and structured notes (`notes_dir`).
-
-    Regardless of the model, precise timing for waiting actions cannot be
-    guaranteed due to latency. If you need to implement a wait, please note that
-    the total waiting time comprises both the time required for the Artemis large
-    model to generate output and the actual waiting duration. (For Flash, the
-    interval between output steps is typically 3-7 seconds, whereas Pro requires
-    25-35 seconds.)
-
-    For long-term repetitive tasks, run the workflow once with this tool to
-    discover the path, then author a dedicated automation script instead of
-    repeatedly delegating.
-
-    This tool is non-blocking and will immediately return a dictionary
-    containing:
-    - `trace_id`: The unique session identifier of the task for status tracking
-    and inspection.
-    - `device_serial`: The assigned target device serial (or "auto-select").
-    - `notes_dir`: (Pro Model Only) The directory where the subagent's execution
-    files/notes are located.
-    - `stdout_log`: The path to the execution framework log.
-    - `stderr_log`: The path to the error log containing critical failures and
-    Python tracebacks (essential for debugging).
-
-    Upon task completion (success or failure), the system will trigger a
-    Reactive Wakeup to notify you.
-
-    CRITICAL BEHAVIORAL RULES:
-    1. **Fallback Timer Constraint**: You **MUST** set a background timer to
-    check the task status at least once every 1 minute as a safety fallback.
-    2. **Post-Task Inspection**: After completion, retrieve and inspect the
-    execution logs (`stderr_log`/`stdout_log`) to verify success.
-    3. **Inspecting Notes (Pro Model Only)**: If running with Pro, you can
-    inspect the notes/plans recorded in `notes_dir` to extract critical
-    execution results passed back by the subagent.
+    ### Follow-up protocol (CRITICAL)
+    1. **Fallback timer**: you MUST set a background timer and check the task
+       status via `mobile_manage_task` at least once every 1 minute — mobile
+       tasks can stall silently, so never rely on the completion wakeup alone.
+    2. **Post-task inspection**: after completion, inspect the execution logs
+       to verify success (`stderr_log` carries critical failures and Python
+       tracebacks — essential for debugging).
+    3. **Pro notes**: for Pro runs, read `notes_dir` to extract the results and
+       plans the subagent recorded.
 
     Args:
-        task_desc: A clear, highly detailed, actionable task description for the
-          mobile subagent. Since execution is autonomous and one-shot, provide
-          all necessary context, exact UI actions to take, and clear termination
-          conditions. If `model="Pro"`, you can explicitly instruct the subagent
-          on what specific information it must record in the notes.
-        conversation_id: Your current active Conversation ID. Critical for
-          routing the wakeup notification.
-        model: Must be either `"Flash"` or `"Pro"`. - Choose `"Flash"` for fast,
-          simple UI tasks under 30 steps without log/video analysis or
-          monitoring/polling needs. - Choose `"Pro"` for complex tasks requiring
-          planning, ADB shell commands, logs, video exploration, or continuous
-          monitoring and polling tasks.
-        locked_app_package: Optional package name of the app to lock execution
-          to. The agent will auto-launch and restrict actions to this app.
-        app_path: Optional path to a local APK to install on the device before
-          running the task.
-        expected_output_desc: Optional (Pro Model Only). If provided, a
-          summarization agent will aggregate the interaction history
-          (motivation, actions, videos) into a summary report saved as
-          "output.md" in `notes_dir`. Ignored if `model="Flash"`.
-        device_serial: Optional Android device serial number (e.g. "63191FDKX00062"
-          or "emulator-5554"). If specified, binds execution strictly to that device,
-          allowing multi-device concurrent automation. If omitted, ARTEMIS will
-          automatically select an available device. Prioritize letting the user select
-          the target device if multiple devices are attached.
+        task_desc: Clear, self-contained task description with all context,
+          exact UI actions, and termination conditions (execution is one-shot).
+          For Pro, may also specify what the subagent must record in its notes.
+        conversation_id: Optional conversation ID used to route the completion
+          wakeup notification back to the caller. Omit if unknown.
+        model: `"Flash"` or `"Pro"` — see model selection above.
+        locked_app_package: Optional package name to lock execution to; the
+          agent auto-launches it and restricts actions to that app.
+        app_path: Optional local APK path to install before running.
+        expected_output_desc: Optional, Pro only. If set, a summarization agent
+          writes a report to `output.md` in `notes_dir`. Ignored for Flash.
+        device_serial: Optional device serial (e.g. "emulator-5554") to bind
+          execution to a specific device; distinct devices run concurrently.
+          If omitted, an available device is selected automatically. When
+          several devices are attached, confirm the target with the user first
+          (`adb devices -l` lists serials and authorization states).
     """
     # 0. Validate and normalize model
     if model.lower() not in ("flash", "pro"):
@@ -162,6 +250,16 @@ def mobile_run_task(
         device_serial=device_serial,
     )
 
+    # 2b. Strict device binding: an explicitly requested serial must be attached and
+    # authorized. Rejecting here prevents the task from silently running on a
+    # different device than the caller asked for. Runs after init_trace so the
+    # rejection carries a trace_id like every other response of this tool.
+    if device_serial:
+        rejection = _validate_device_serial(device_serial)
+        if rejection:
+            trace_store.update_trace_status(trace_id, "failed", error=rejection["error"])
+            return {"trace_id": trace_id, **rejection}
+
     # 3. Dispatch via unified Artemis Daemon scheduler if available (unless standalone forced)
     if os.environ.get("ARTEMIS_STANDALONE") != "1":
         try:
@@ -181,6 +279,15 @@ def mobile_run_task(
                     conversation_id=conversation_id,
                     base_url=base_url,
                 )
+                if resp and resp.get("status") == "rejected":
+                    rejection_error = resp.get("error") or "Task rejected by Artemis Daemon."
+                    trace_store.update_trace_status(trace_id, "failed", error=rejection_error)
+                    return {
+                        "trace_id": trace_id,
+                        "status": "failed",
+                        "error": rejection_error,
+                        "message": f"Task rejected by Artemis Daemon: {rejection_error}",
+                    }
                 if resp and resp.get("tasks"):
                     assigned_sid = resp["tasks"][0].get("session_id", trace_id)
                     trace_store.update_trace_status(
@@ -275,7 +382,7 @@ def mobile_run_task(
             "--model",
             canonical_model,
             "--conversation-id",
-            conversation_id,
+            conversation_id or "",
         ]
         if locked_app_package:
             cmd.extend(["--locked-app-package", locked_app_package])
@@ -330,6 +437,11 @@ def mobile_run_task(
             status_data["queue_ticket"] = queue_ticket
             trace_store.write_status(trace_id, status_data)
 
+        # 6. Arm a watchdog: a runner that never opens its log files is hung in
+        # interpreter startup and must be killed instead of squatting on the
+        # queue as 'running' forever.
+        _start_spawn_watchdog(trace_id, proc.pid, queue_ticket, conversation_id)
+
         trace_dir = trace_store.get_trace_dir(trace_id)
         stdout_log_path = os.path.join(trace_dir, "stdout.log")
         stderr_log_path = os.path.join(trace_dir, "stderr.log")

mcp_server/utils/trace_store.py

@@ -57,7 +57,7 @@ def init_trace(
     trace_id: str,
     task_desc: str,
     model: str,
-    conversation_id: str,
+    conversation_id: str | None = None,
     device_serial: str | None = None,
 ) -> dict[str, Any]:
     """Initializes the trace directory and creates the initial status.json file."""

tests/unit/admin_console/test_task_queue_service.py

@@ -667,6 +667,10 @@ async def test_queue_worker_notifies_conversation():
         patch("apps.admin_console.services.task_queue_service.media_service"),
         patch("mcp_server.notifiers.notify") as mock_notify,
         patch("apps.admin_console.services.task_queue_service.session_repo") as mock_repo,
+        patch(
+            "artemis.runtime.device_pool.device_pool.list_devices_async",
+            new=AsyncMock(return_value=[]),
+        ),
     ):
         mock_repo.get_running_session_id.return_value = None
 
@@ -849,6 +853,11 @@ async def test_enqueue_tasks_debounces_rapid_identical_submissions():
     with (
         patch("apps.admin_console.services.task_queue_service.session_repo"),
         patch("apps.admin_console.services.task_queue_service.DeviceExecutionLock.reserve", return_value="ticket-456"),
+        patch(
+            "artemis.runtime.device_pool.device_pool.list_devices_async",
+            new=AsyncMock(return_value=[]),
+        ),
+        patch.object(TaskQueueService, "ensure_worker_running"),
     ):
         res1 = await task_queue_service.enqueue_tasks(["Rapid duplicate goal"], device_serial="dev-1")
         assert len(state.queue_items) == 1

tests/unit/agents/test_failure_analyzer_tools.py

@@ -304,9 +304,11 @@ async def test_input_text_happy_path(mock_context, mock_controller):
         ctx=mock_context,
     )
     assert "Executed typing 'hello'." in outcome
-    mock_controller.tap_at.assert_called_once_with(540, 1200)
+    # Focus goes through ensure_focus_at_coords (keyword-style tap), and typing
+    # never re-clears: the clear already happened via erase_text.
+    mock_controller.tap_at.assert_called_once_with(x=540, y=1200)
     mock_controller.erase_text.assert_called_once()
-    mock_controller.type_text.assert_called_once_with("hello")
+    mock_controller.type_text.assert_called_once_with("hello", clear_existing=False)
 
 
 @pytest.mark.asyncio
@@ -396,8 +398,10 @@ async def test_press_key_input_validation(mock_context, mock_controller):
         controller=mock_controller,
         ctx=mock_context,
     )
-    # The current execution doesn't raise error on unknown keys, just logs error
-    assert "Error executing key press 'INVALID_KEY'." in outcome
+    # Unknown keycodes are forwarded verbatim to the driver (historical adb_server
+    # behavior); the mock driver accepts them, so the press reports success.
+    assert "Executed key press 'INVALID_KEY'." in outcome
+    mock_controller.press_key.assert_called_once_with("INVALID_KEY")
 
 
 # ==========================================
@@ -409,8 +413,10 @@ async def test_press_key_input_validation(mock_context, mock_controller):
 async def test_manage_app_happy_path(mock_context, mock_controller):
     state = DummyState()
     with (
-        patch("artemis.agents.validator.tool_declarations.find_package") as mock_find_package,
-        patch("artemis.agents.validator.tool_declarations.launch_app_with_retries") as mock_launch,
+        # The device-call bodies moved into the actuator layer, which imports these
+        # lazily from their source modules -- patch them at the source.
+        patch("artemis.tools.mobile.launch_app.find_package") as mock_find_package,
+        patch("artemis.utils.app_launch_utils.launch_app_with_retries") as mock_launch,
     ):
         mock_find_package.return_value = "com.google.android.youtube"
         mock_launch.return_value = (True, "")
@@ -430,7 +436,7 @@ async def test_manage_app_happy_path(mock_context, mock_controller):
 @pytest.mark.asyncio
 async def test_manage_app_input_validation(mock_context, mock_controller):
     state = DummyState()
-    with patch("artemis.agents.validator.tool_declarations.find_package") as mock_find_package:
+    with patch("artemis.tools.mobile.launch_app.find_package") as mock_find_package:
         mock_find_package.return_value = None
 
         outcome, _, _, _ = await _exec_manage_app(

tests/unit/agents/test_prompt_assembly.py

@@ -0,0 +1,233 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Prompt assembly tests: full-set output is byte-stable, absent tools leave no trace."""
+
+from pathlib import Path
+import re
+
+from jinja2 import Template
+import pytest
+
+from artemis.agents.operator.prompt_builder import load_operator_prompts
+from artemis.agents.operator.prompts import (
+    OPERATOR_PROMPT_TOOLSET,
+    apply_operator_prompt_contract,
+)
+from artemis.agents.prompt_assembly import gate_segment, render_tool_enum
+from artemis.agents.validator.failure_analyzer import (
+    FailureAnalysisStrategy,
+    FailureAnalyzer,
+    PixelTargetDisappearedStrategy,
+    TargetDisappearedStrategy,
+)
+from artemis.agents.validator.validator import ValidationErrorCategory
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+
+OPERATOR_DEVICE_TOOLS = (
+    "click",
+    "input_text",
+    "swipe",
+    "press_key",
+    "manage_app",
+    "wait_for_delay",
+    "long_press",
+)
+
+
+def _tool_refs(text: str, tool: str) -> list[str]:
+    """Finds real tool references (backticked or call form), ignoring prose."""
+    return re.findall(rf"(`{tool}`|\b{tool}\()", text)
+
+
+# --- render_tool_enum ----------------------------------------------------------------
+
+
+def test_enum_plain_list():
+    out = render_tool_enum(("a", "b", "c"), {"a", "b", "c"})
+    assert out == "`a`, `b`, `c`"
+
+
+def test_enum_oxford_or_and():
+    tools = ("a", "b", "c")
+    assert render_tool_enum(tools, set(tools), final_sep="or") == "`a`, `b`, or `c`"
+    assert render_tool_enum(tools, set(tools), final_sep="and") == "`a`, `b`, and `c`"
+
+
+def test_enum_two_items_no_oxford_comma():
+    assert render_tool_enum(("a", "b"), {"a", "b"}, final_sep="or") == "`a` or `b`"
+
+
+def test_enum_single_and_empty():
+    assert render_tool_enum(("a", "b"), {"a"}) == "`a`"
+    assert render_tool_enum(("a", "b"), set()) == ""
+
+
+def test_gate_segment():
+    assert gate_segment("teach", {"swipe"}, "swipe") == "teach"
+    assert gate_segment("teach", set(), "swipe") == ""
+    assert gate_segment("teach", {"a"}, "a", "b") == ""
+
+
+# --- Operator prompt assembly --------------------------------------------------------
+
+
+def test_full_toolset_is_the_default():
+    """``available_tools=None`` must equal the explicit full set, byte for byte."""
+    for template in load_operator_prompts().values():
+        assert apply_operator_prompt_contract(template) == apply_operator_prompt_contract(
+            template, available_tools=OPERATOR_PROMPT_TOOLSET
+        )
+
+
+@pytest.mark.parametrize("tool", OPERATOR_DEVICE_TOOLS + ("video_analyzer",))
+def test_removed_tool_leaves_no_reference(tool):
+    """The executable definition of 'an absent tool costs the model nothing'."""
+    for name, template in load_operator_prompts().items():
+        out = apply_operator_prompt_contract(
+            template, available_tools=OPERATOR_PROMPT_TOOLSET - {tool}
+        )
+        assert not _tool_refs(out, tool), f"'{tool}' still referenced in {name}"
+
+
+def test_removed_swipe_takes_its_teaching_along():
+    """Gating removes the drag/slider teaching, not just the backticked name."""
+    template = load_operator_prompts()["main_template"]
+    out = apply_operator_prompt_contract(
+        template, available_tools=OPERATOR_PROMPT_TOOLSET - {"swipe"}
+    )
+    assert "swipe/drag" not in out
+    assert "sliders/SeekBars" not in out
+    # The generic gesture-scope sentences survive.
+    assert "Action Scope & Interaction Precision" in out
+
+
+def test_removed_wait_for_delay_keeps_interval_line_coherent():
+    """Only the wait_for_delay parenthetical goes; the SOP grammar line stays."""
+    template = load_operator_prompts()["main_template"]
+    out = apply_operator_prompt_contract(
+        template, available_tools=OPERATOR_PROMPT_TOOLSET - {"wait_for_delay"}
+    )
+    assert "`Interval: <Interval>`: Declared polling cadence." in out
+    assert "Loading & Transitions" not in out
+
+
+def test_reduced_enums_stay_well_formed():
+    template = load_operator_prompts()["main_template"]
+    out = apply_operator_prompt_contract(
+        template,
+        available_tools=OPERATOR_PROMPT_TOOLSET - {"manage_app", "wait_for_delay"},
+    )
+    assert (
+        "Physical device actions (`click`, `input_text`, `swipe`, `press_key`,"
+        " `long_press`)" in out
+    )
+    assert (
+        "Turn-Ending Action (`click`, `swipe`, `input_text`, `long_press`, or"
+        " `press_key`)" in out
+    )
+
+
+def test_full_set_enum_slots_render_verbatim():
+    """With every tool present the historical enumeration wording is reproduced."""
+    template = load_operator_prompts()["main_template"]
+    out = apply_operator_prompt_contract(template)
+    assert (
+        "Physical device actions (`click`, `input_text`, `swipe`, `press_key`,"
+        " `manage_app`, `wait_for_delay`, `long_press`)" in out
+    )
+    assert (
+        "Turn-Ending Action (`click`, `swipe`, `input_text`, `long_press`,"
+        " `press_key`, `manage_app`, or `wait_for_delay`)" in out
+    )
+    assert (
+        "(`ask_explorer`, `ask_diagnoser`, `video_analyzer`, `run_adb_command`,"
+        " `manage_task`, `analyze_task_output`, `read_note`, `list_notes`, and"
+        " `save_note`)" in out
+    )
+
+
+# --- Flash prompt assembly -----------------------------------------------------------
+
+
+def _render_flash(available_tools: frozenset[str]) -> str:
+    template_text = (REPO_ROOT / "artemis/agents/flash/flash_runner.md").read_text(
+        encoding="utf-8"
+    )
+    return Template(template_text).render(goal="test goal", available_tools=available_tools)
+
+
+FLASH_FULL = frozenset({"manage_app", "wait_for_delay", "click_sequence", "click", "swipe"})
+
+
+def test_flash_full_set_keeps_both_segments():
+    out = _render_flash(FLASH_FULL)
+    assert "**App Launching**" in out
+    assert "**Timed Waiting & Transitions**" in out
+    assert "{%" not in out
+
+
+def test_flash_without_manage_app_drops_app_launching():
+    out = _render_flash(FLASH_FULL - {"manage_app"})
+    assert "**App Launching**" not in out
+    assert not _tool_refs(out, "manage_app")
+    # The neighbouring numbered rule survives.
+    assert "**Screenshot Pruning Awareness**" in out
+
+
+def test_flash_without_wait_for_delay_drops_timed_waiting():
+    out = _render_flash(FLASH_FULL - {"wait_for_delay"})
+    assert "**Timed Waiting & Transitions**" not in out
+    assert not _tool_refs(out, "wait_for_delay")
+    assert "**State Drift & Progression Tolerance**" in out
+
+
+# --- FailureAnalyzer strategy gating -------------------------------------------------
+
+
+def _analyzer() -> FailureAnalyzer:
+    return FailureAnalyzer.__new__(FailureAnalyzer)  # _select_strategy needs no ctx
+
+
+def test_strategy_selection_unchanged_without_gating():
+    analyzer = _analyzer()
+    assert isinstance(
+        analyzer._select_strategy(ValidationErrorCategory.TARGET_DISAPPEARED),
+        TargetDisappearedStrategy,
+    )
+    assert isinstance(
+        analyzer._select_strategy(ValidationErrorCategory.PIXEL_TARGET_DISAPPEARED),
+        PixelTargetDisappearedStrategy,
+    )
+
+
+def test_strategy_falls_back_when_required_tool_missing():
+    """Strategy + prompt are one unit: no click_sequence, no disappeared-prompts."""
+    analyzer = _analyzer()
+    strategy = analyzer._select_strategy(
+        ValidationErrorCategory.TARGET_DISAPPEARED,
+        available_tools=frozenset({"click", "swipe"}),
+    )
+    assert type(strategy) is FailureAnalysisStrategy
+    assert strategy.get_prompt_template_name() == "failure_analyzer.md"
+
+
+def test_strategy_kept_when_required_tool_present():
+    analyzer = _analyzer()
+    strategy = analyzer._select_strategy(
+        ValidationErrorCategory.PIXEL_TARGET_DISAPPEARED,
+        available_tools=frozenset({"click_sequence"}),
+    )
+    assert isinstance(strategy, PixelTargetDisappearedStrategy)

tests/unit/agents/test_validator.py

@@ -12,13 +12,25 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""ValidatorNode tests over the in-process unified action session.
+
+The Validator no longer spawns a stdio MCP subprocess; it calls a shared
+``ActionSession`` whose device actions return structured ``ActionResult`` objects.
+``FakeActionSession`` below stands in for it: ``action_handler`` decides each
+action's ``(ok, message)``, ``screenshot`` feeds the polling loop, and ``hierarchy``
+feeds the safety-net XML validation.
+"""
+
 import json
 from unittest.mock import AsyncMock, MagicMock, Mock, patch
+
 from langchain_core.messages import AIMessage
+import pytest
+
 from artemis.agents.validator.failure_analyzer import ValidationErrorCategory
 from artemis.agents.validator.validator import ValidatorNode
 from artemis.context import ArtemisContext
-import pytest
+from artemis.mcp.action_types import ActionCode, ActionResult
 
 
 class DummyState:
@@ -38,6 +50,46 @@ class DummyState:
         return update
 
 
+class FakeActionSession:
+    """Test double for artemis.mcp.action_session.ActionSession."""
+
+    def __init__(self):
+        self.started = True
+        self.calls: list[tuple[str, dict]] = []
+        # (name, args) -> (ok, message)
+        self.action_handler = lambda name, args: (True, "")
+        # str | callable | Exception
+        self.screenshot = "ZHVtbXlfZGF0YQ=="  # b64("dummy_data")
+        self.hierarchy: list | Exception = []
+
+    async def call(self, name, args):
+        self.calls.append((name, args))
+        ok, msg = self.action_handler(name, args)
+        return ActionResult(
+            ok=ok,
+            code=ActionCode.OK if ok else ActionCode.DEVICE_ERROR,
+            action=name,
+            message=msg,
+        )
+
+    async def screenshot_b64(self, timeout=None):
+        shot = self.screenshot
+        if isinstance(shot, Exception):
+            raise shot
+        return shot() if callable(shot) else shot
+
+    async def ui_hierarchy(self, timeout=None):
+        if isinstance(self.hierarchy, Exception):
+            raise self.hierarchy
+        return self.hierarchy
+
+    async def aclose(self):
+        pass
+
+    def calls_for(self, name: str) -> list[dict]:
+        return [args for n, args in self.calls if n == name]
+
+
 @pytest.fixture
 def mock_context(tmp_path):
     ctx = Mock(spec=ArtemisContext)
@@ -45,6 +97,9 @@ def mock_context(tmp_path):
     ctx.data_engine = Mock()
     ctx.data_engine.base_dir = tmp_path
     ctx.data_engine.get_relative_time.return_value = 1.0
+    ctx.device = Mock()
+    ctx.device.device_width = 1080
+    ctx.device.device_height = 2400
     return ctx
 
 
@@ -57,31 +112,18 @@ def temp_screenshot(tmp_path):
 
 @pytest.fixture
 def mock_mcp():
-    with (
-        patch("mcp.client.stdio.stdio_client") as mock_stdio,
-        patch("artemis.agents.validator.validator.ClientSession") as mock_session_cls,
-    ):
-        mock_ctx = AsyncMock()
-        mock_ctx.__aenter__.return_value = (Mock(), Mock())
-        mock_stdio.return_value = mock_ctx
+    fake = FakeActionSession()
 
-        mock_session = AsyncMock()
-        mock_session.initialize = AsyncMock()
-        mock_session_cls.return_value = mock_session
+    async def _get_session(ctx, actuator=None):
+        return fake
 
-        yield mock_session
+    with patch("artemis.agents.validator.validator.get_action_session", _get_session):
+        yield fake
 
 
 @pytest.mark.asyncio
 async def test_validator_success(mock_mcp, mock_context, temp_screenshot):
     """Test that ValidatorNode executes actions successfully."""
-    # Mock MCP calls: screenshot, tap, screenshot
-    mock_mcp.call_tool.side_effect = [
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # pre-screenshot
-        Mock(content=[Mock(text="Success")]),  # tap action
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # post-screenshot
-    ]
-
     decisions = json.dumps([{"action": "tap", "coordinates": [105, 205]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -95,78 +137,23 @@ async def test_validator_success(mock_mcp, mock_context, temp_screenshot):
     assert len(report["execution"]) == 1
     assert report["execution"][0]["action"] == "tap"
     assert "attempts" not in report["execution"][0]
+    # The Operator's tap verb was translated to the canonical click tool.
+    assert len(mock_mcp.calls_for("click")) == 1
 
 
-@pytest.mark.asyncio
-async def test_failed_mcp_handshake_exits_contexts_and_disables_child_awake_policy():
-    """A handshake failure must not leave AnyIO cancellation scopes behind."""
-    events = []
-
-    class FakeClientContext:
-        async def __aenter__(self):
-            events.append("client_enter")
-            return Mock(), Mock()
-
-        async def __aexit__(self, exc_type, exc, traceback):
-            events.append("client_exit")
-
-    class FakeSession:
-        async def __aenter__(self):
-            events.append("session_enter")
-            return self
-
-        async def __aexit__(self, exc_type, exc, traceback):
-            events.append("session_exit")
-
-        async def initialize(self):
-            raise TimeoutError("handshake timed out")
-
-    ctx = Mock(spec=ArtemisContext)
-    ctx.mcp_client_ctx = None
-    ctx.mcp_session = None
-    fake_client_ctx = FakeClientContext()
-    fake_session = FakeSession()
-    captured_parameters = []
-
-    def fake_stdio_client(parameters):
-        captured_parameters.append(parameters)
-        return fake_client_ctx
-
-    node = ValidatorNode(ctx)
-    with (
-        patch("artemis.agents.validator.validator.stdio_client", fake_stdio_client),
-        patch("artemis.agents.validator.validator.ClientSession", return_value=fake_session),
-        patch("artemis.agents.validator.validator.AdbClient") as adb_client,
-        patch.object(node, "_kill_mcp_server_instantly") as emergency_kill,
-    ):
-        adb_client.return_value.device_list.return_value = []
-        result = await node._get_mcp_session()
-
-    assert result is None
-    assert events == ["client_enter", "session_enter", "session_exit", "client_exit"]
-    assert ctx.mcp_session is None
-    assert ctx.mcp_client_ctx is None
-    assert captured_parameters[0].env["ARTEMIS_KEEP_DEVICE_AWAKE"] == "false"
-    emergency_kill.assert_not_called()
-
+# NOTE: upstream's test_failed_mcp_handshake_exits_contexts_and_disables_child_awake_policy
+# guarded the stdio-subprocess handshake teardown, machinery this migration removed
+# entirely. Its hazard class (leaked AnyIO cancel scopes) is now pinned by
+# tests/unit/mcp/test_action_session.py against the in-process ActionSession.
 
 @pytest.mark.asyncio
 async def test_validator_failure_analysis(mock_mcp, mock_context, temp_screenshot):
     """Test that ValidatorNode triggers failure analysis on error and handles
     cannot_fix via tool.
     """
-    tap_count = 0
-
-    def mock_call_tool(name, args):
-        nonlocal tap_count
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "tap":
-            tap_count += 1
-            return Mock(content=[Mock(text="Error: Element not found")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
+    mock_mcp.action_handler = lambda name, args: (
+        (False, "Error: Element not found") if name == "click" else (True, "")
+    )
 
     decisions = json.dumps([{"action": "tap", "coordinates": [105, 205]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
@@ -203,18 +190,15 @@ async def test_validator_repair_success(mock_mcp, mock_context, temp_screenshot)
     """
     tap_count = 0
 
-    def mock_call_tool(name, args):
+    def handler(name, args):
         nonlocal tap_count
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "tap":
+        if name == "click":
             tap_count += 1
-            if tap_count <= 2:  # First tap fails
-                return Mock(content=[Mock(text="Error: Element not found")])
-            return Mock(content=[Mock(text="Success")])
-        return Mock(content=[Mock(text="Success")])
+            if tap_count <= 2:  # First action fails on both validator attempts
+                return False, "Error: Element not found"
+        return True, ""
 
-    mock_mcp.call_tool.side_effect = mock_call_tool
+    mock_mcp.action_handler = handler
 
     # Two actions planned initially
     decisions = json.dumps(
@@ -254,12 +238,6 @@ async def test_validator_repair_success(mock_mcp, mock_context, temp_screenshot)
 @pytest.mark.asyncio
 async def test_validator_wait_for_delay(mock_mcp, mock_context, temp_screenshot):
     """Test that wait_for_delay executes successfully."""
-
-    def mock_call(name, args):
-        return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-
-    mock_mcp.call_tool.side_effect = mock_call
-
     decisions = json.dumps([{"action": "wait_for_delay", "time_in_ms": 10}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -272,19 +250,13 @@ async def test_validator_wait_for_delay(mock_mcp, mock_context, temp_screenshot)
     assert "execution" in report
     assert len(report["execution"]) == 1
     assert report["execution"][0]["action"] == "wait_for_delay"
+    # wait_for_delay is a pure client-side sleep, never a session call.
+    assert mock_mcp.calls_for("wait_for_delay") == []
 
 
 @pytest.mark.asyncio
 async def test_validator_focus_and_clear_text_no_ui_change(mock_mcp, mock_context, temp_screenshot):
     """Test that focus_and_clear_text executes successfully even if no UI change is detected."""
-
-    def mock_call(name, args):
-        if name == "focus_and_clear_text":
-            return Mock(content=[Mock(text="Success")])
-        return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-
-    mock_mcp.call_tool.side_effect = mock_call
-
     decisions = json.dumps([{"action": "focus_and_clear_text", "coordinates": [400, 500]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -297,6 +269,7 @@ async def test_validator_focus_and_clear_text_no_ui_change(mock_mcp, mock_contex
     assert "execution" in report
     assert len(report["execution"]) == 1
     assert report["execution"][0]["action"] == "focus_and_clear_text"
+    assert len(mock_mcp.calls_for("focus_and_clear_text")) == 1
 
 
 @pytest.mark.asyncio
@@ -304,16 +277,6 @@ async def test_validator_silent_failure_treated_as_success(mock_mcp, mock_contex
     """Test that silent failure (exec succeeds but no UI change) is treated as
     success and does not trigger FailureAnalyzer.
     """
-
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "tap":
-            return Mock(content=[Mock(text="Success")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps([{"action": "tap", "coordinates": [105, 205]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -344,13 +307,7 @@ async def test_validator_records_skipped_actions_on_cannot_fix(
     mock_mcp, mock_context, temp_screenshot
 ):
     """Test that ValidatorNode marks unexecuted actions as Skipped when repair fails."""
-
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        return Mock(content=[Mock(text="Error: Connection lost")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
+    mock_mcp.action_handler = lambda name, args: (False, "Error: Connection lost")
 
     # Two actions planned
     decisions = json.dumps(
@@ -399,7 +356,7 @@ async def test_validator_pre_execution_validation_and_repair(
     """Test that pre-execution validation fails when element changes, and is
     repaired by FailureAnalyzer.
     """
-    mock_live_elements = [
+    mock_mcp.hierarchy = [
         {
             "text": "Sign Up",
             "bounds": "[100,200][300,300]",
@@ -407,17 +364,6 @@ async def test_validator_pre_execution_validation_and_repair(
         }
     ]
 
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "get_ui_hierarchy":
-            return Mock(content=[Mock(text=json.dumps(mock_live_elements))])
-        if name == "tap":
-            return Mock(content=[Mock(text="Success")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps(
         [
             {
@@ -477,7 +423,7 @@ async def test_validator_pre_execution_validation_self_healing(
     mock_mcp, mock_context, temp_screenshot
 ):
     """Test that pre-execution validation succeeds and self-heals when element shifts slightly."""
-    mock_live_elements = [
+    mock_mcp.hierarchy = [
         {
             "text": "Login",
             "bounds": "[100,220][300,320]",
@@ -485,21 +431,6 @@ async def test_validator_pre_execution_validation_self_healing(
         }
     ]
 
-    tapped_coordinates = None
-
-    def mock_call_tool(name, args):
-        nonlocal tapped_coordinates
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "get_ui_hierarchy":
-            return Mock(content=[Mock(text=json.dumps(mock_live_elements))])
-        if name == "tap":
-            tapped_coordinates = args.get("coordinates")
-            return Mock(content=[Mock(text="Success")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps(
         [
             {
@@ -518,8 +449,12 @@ async def test_validator_pre_execution_validation_self_healing(
     with patch("artemis.utils.image_diff.check_ui_change", return_value=True):
         await node(state)
 
-    # Center of [100, 220][300, 320] is [200, 270]
-    assert tapped_coordinates == [200, 270]
+    # Center of [100, 220][300, 320] is pixel [200, 270]; the healed coordinates
+    # travel to the canonical click tool normalized to 0-1000 on a 1080x2400 screen:
+    # round(200 * 1000 / 1080) = 185, round(270 * 1000 / 2400) = 112.
+    clicks = mock_mcp.calls_for("click")
+    assert len(clicks) == 1
+    assert clicks[0]["target"] == [185, 112]
 
 
 @pytest.mark.asyncio
@@ -531,7 +466,7 @@ async def test_validator_pre_execution_validation_anonymous_occupant(
     """
     # The live screen contains an anonymous clickable view covering
     # target coordinates [200, 250]
-    mock_live_elements = [
+    mock_mcp.hierarchy = [
         {
             "text": "",
             "bounds": "[150,200][250,300]",
@@ -540,15 +475,6 @@ async def test_validator_pre_execution_validation_anonymous_occupant(
         }
     ]
 
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "get_ui_hierarchy":
-            return Mock(content=[Mock(text=json.dumps(mock_live_elements))])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps(
         [
             {
@@ -596,12 +522,6 @@ async def test_validator_pre_execution_validation_anonymous_occupant(
 @pytest.mark.asyncio
 async def test_validator_pixel_validation_success(mock_mcp, mock_context, temp_screenshot):
     """Test that the pixel safety net succeeds when Gemini reports target is present."""
-    mock_mcp.call_tool.side_effect = [
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # live screenshot for pixel check
-        Mock(content=[Mock(text="Success")]),  # tap action
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # post-screenshot
-    ]
-
     decisions = json.dumps([{"action": "tap", "coordinates": [100, 200]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -645,14 +565,6 @@ async def test_validator_pixel_validation_failure(mock_mcp, mock_context, temp_s
     """Test that the pixel safety net fails and triggers FailureAnalyzer
     when Gemini reports target is missing.
     """
-
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps([{"action": "tap", "coordinates": [100, 200]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -697,23 +609,15 @@ async def test_validator_pixel_validation_failure(mock_mcp, mock_context, temp_s
 
 
 @pytest.mark.asyncio
-@patch("artemis.agents.validator.validator.find_package")
-@patch("artemis.utils.app_launch_utils.launch_app_with_retries")
-async def test_validator_launch_app_passes_use_fallback_mcp(
-    mock_launch_app, mock_find_package, mock_mcp, mock_context, temp_screenshot
+async def test_validator_launch_app_routes_through_manage_app(
+    mock_mcp, mock_context, temp_screenshot
 ):
-    """Test that ValidatorNode calls find_package with use_fallback=False
-    for launch_app action in MCP mode.
+    """Test that a launch_app action item routes to the canonical manage_app tool.
+
+    Package resolution (find_package with use_fallback=False) now happens inside the
+    actuator's manage_app implementation and is covered by the failure-analyzer tool
+    tests; the Validator's contract is the translation and single dispatch.
     """
-    mock_find_package.return_value = "com.example.app"
-    mock_launch_app.return_value = (True, None)
-
-    # Mock MCP calls: screenshot (pre), screenshot (post)
-    mock_mcp.call_tool.side_effect = [
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # pre-screenshot
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # post-screenshot
-    ]
-
     decisions = json.dumps([{"action": "launch_app", "app_name": "My App"}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
 
@@ -721,27 +625,17 @@ async def test_validator_launch_app_passes_use_fallback_mcp(
         node = ValidatorNode(mock_context)
         result = await node(state)
 
-    mock_find_package.assert_called_once_with(mock_context, "My App", use_fallback=False)
-    mock_launch_app.assert_called_once_with(mock_context, "com.example.app")
+    manage_calls = mock_mcp.calls_for("manage_app")
+    assert manage_calls == [{"action": "launch", "app_name": "My App"}]
     assert "last_execution_result" in result
 
 
 @pytest.mark.asyncio
-@patch("artemis.agents.validator.validator.find_package")
-@patch("artemis.utils.app_launch_utils.launch_app_with_retries")
-async def test_validator_launch_app_failure_no_retry(
-    mock_launch_app, mock_find_package, mock_mcp, mock_context, temp_screenshot
-):
+async def test_validator_launch_app_failure_no_retry(mock_mcp, mock_context, temp_screenshot):
     """Test that ValidatorNode does NOT retry launch_app action on failure."""
-    mock_find_package.return_value = "com.example.app"
-    mock_launch_app.return_value = (False, "Error: Force close")
-
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
+    mock_mcp.action_handler = lambda name, args: (
+        (False, "Error: Force close") if name == "manage_app" else (True, "")
+    )
 
     decisions = json.dumps([{"action": "launch_app", "app_name": "My App"}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
@@ -760,13 +654,9 @@ async def test_validator_launch_app_failure_no_retry(
         node = ValidatorNode(mock_context)
         result = await node(state)
 
-    # Verify find_package was called only once
-    mock_find_package.assert_called_once_with(mock_context, "My App", use_fallback=False)
-    # Verify launch_app_with_retries was called only once
-    # (no retry by ValidatorNode itself since it relies on launch_app_with_retries)
-    mock_launch_app.assert_called_once_with(mock_context, "com.example.app")
+    # launch_app allows a single attempt -- no validator-level retry.
+    assert len(mock_mcp.calls_for("manage_app")) == 1
 
-    # Verify attempts list has only 1 element
     assert "last_execution_result" in result
     report = result["last_execution_result"]
     assert len(report["execution"]) == 1
@@ -783,7 +673,7 @@ async def test_validator_pre_execution_validation_disappeared_not_shifted(
     """
     # Live hierarchy only contains a giant background/container
     # containing the text "Sign Up"
-    mock_live_elements = [
+    mock_mcp.hierarchy = [
         {
             "text": "Sign Up",
             "bounds": "[0,0][1080,2400]",
@@ -791,15 +681,6 @@ async def test_validator_pre_execution_validation_disappeared_not_shifted(
         }
     ]
 
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "get_ui_hierarchy":
-            return Mock(content=[Mock(text=json.dumps(mock_live_elements))])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps(
         [
             {
@@ -850,12 +731,6 @@ async def test_validator_pre_execution_validation_ocr_direct_to_pixel(
     """Test that OCR-derived elements bypass XML validation and
     directly use pixel-based validation.
     """
-    mock_mcp.call_tool.side_effect = [
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # live screenshot for pixel check
-        Mock(content=[Mock(text="Success")]),  # tap action
-        Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")]),  # post-screenshot
-    ]
-
     decisions = json.dumps(
         [
             {
@@ -905,7 +780,7 @@ async def test_validator_pre_execution_xml_failure_not_overridden_when_pixel_byp
     """Test that when XML validation fails AND Pixel validation is bypassed
     (PIXEL_BYPASSED), the XML failure is NOT overridden.
     """
-    mock_live_elements = [
+    mock_mcp.hierarchy = [
         {
             "text": "Sign Up",
             "bounds": "[100,200][300,300]",
@@ -913,15 +788,6 @@ async def test_validator_pre_execution_xml_failure_not_overridden_when_pixel_byp
         }
     ]
 
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="ZHVtbXlfZGF0YQ==")])
-        if name == "get_ui_hierarchy":
-            return Mock(content=[Mock(text=json.dumps(mock_live_elements))])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
-
     decisions = json.dumps(
         [
             {
@@ -970,17 +836,13 @@ async def test_validator_pre_execution_xml_failure_not_overridden_when_pixel_byp
 async def test_validator_failure_screenshot_mcp_error_handled_safely(
     mock_mcp, mock_context, temp_screenshot
 ):
-    """Test that when take_screenshot fails on MCP server and returns an error text,
-    the ValidatorNode does not crash with base64 decoding error.
+    """Test that when take_screenshot fails on the session, the ValidatorNode does
+    not crash -- the failure screenshot is simply absent.
     """
-    def mock_call_tool(name, args):
-        if name == "take_screenshot":
-            return Mock(content=[Mock(text="Error: ADB connection lost")])
-        if name == "tap":
-            return Mock(content=[Mock(text="Error: Target not found")])
-        return Mock(content=[Mock(text="Success")])
-
-    mock_mcp.call_tool.side_effect = mock_call_tool
+    mock_mcp.screenshot = RuntimeError("Error: ADB connection lost")
+    mock_mcp.action_handler = lambda name, args: (
+        (False, "Error: Target not found") if name == "click" else (True, "")
+    )
 
     decisions = json.dumps([{"action": "tap", "coordinates": [105, 205]}])
     state = DummyState(structured_decisions=decisions, latest_screenshot=temp_screenshot)
@@ -1002,4 +864,3 @@ async def test_validator_failure_screenshot_mcp_error_handled_safely(
     assert report["status"] == "failed"
     assert len(report["execution"]) == 1
     assert report["execution"][0]["action"] == "tap"
-

tests/unit/core/test_platform.py

@@ -55,7 +55,9 @@ def test_darwin_platform_paths():
     """Verify macOS platform paths adhere to Apple Library standards."""
     darwin_p = DarwinPlatform()
     assert darwin_p.os_type == OSType.MACOS
-    assert "Library/Application Support" in str(darwin_p.paths.config_dir)
+    # Compare path components so the assertion holds regardless of the host
+    # OS path separator used by str().
+    assert darwin_p.paths.config_dir.parts[-3:] == ("Library", "Application Support", "artemis")
     assert darwin_p.process.path_separator == ":"
 
 

tests/unit/data_engine/test_latency_optimizations_deep.py

@@ -392,10 +392,12 @@ async def test_validator_pre_execution_loop_reverted_to_exact_safety_contract(
     mock_artemis_ctx.data_engine = MagicMock()
 
     node = ValidatorNode(mock_artemis_ctx)
+    # The Validator now talks to the in-process unified action session.
     session = MagicMock()
-    session.call_tool = AsyncMock(
-        return_value=MagicMock(content=[MagicMock(text="ZHVtbXlfZGF0YQ==")])
-    )
+    session.started = True
+    session.screenshot_b64 = AsyncMock(return_value="ZHVtbXlfZGF0YQ==")
+    session.ui_hierarchy = AsyncMock(return_value=[])
+    session.call = AsyncMock()
 
     decisions = json.dumps(
         [
@@ -421,6 +423,10 @@ async def test_validator_pre_execution_loop_reverted_to_exact_safety_contract(
     )
 
     with (
+        patch(
+            "artemis.agents.validator.validator.get_action_session",
+            AsyncMock(return_value=session),
+        ),
         patch.object(
             ValidatorNode, "_get_initial_screenshot", new_callable=AsyncMock
         ) as mock_get_screen,

tests/unit/mcp/test_action_manifest.py

@@ -0,0 +1,294 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Prompt <-> manifest consistency and actuator contract tests.
+
+The scan below re-derives the manifest classification from the prompt sources, so
+adding a tool name to a prompt without classifying it in
+``artemis/mcp/action_manifest.py`` fails here rather than at runtime.
+"""
+
+import json
+from pathlib import Path
+import re
+
+import pytest
+
+from artemis.core.tool_declaration import ToolDeclaration
+from artemis.mcp.action_manifest import (
+    ActuatorContractError,
+    AGENT_ROLES,
+    ALL_KNOWN_TOOLS,
+    BACKEND_INDEPENDENT_TOOLS,
+    DEVICE_ACTIONS,
+    ExtensionTool,
+    INTERNAL_ACTIONS,
+    OPTIONAL_ACTIONS,
+    REQUIRED_ACTIONS,
+    available_device_actions,
+    filter_declarations,
+    validate_actuator,
+)
+
+REPO_ROOT = Path(__file__).resolve().parents[3]
+
+# Prompt sources belonging to the three agents this manifest governs (plus the
+# Validator's safety net). Other agents (log_analyzer, image_processor, ...) have their
+# own tool universes and are deliberately out of scope.
+SCOPED_PROMPT_FILES = [
+    "artemis/agents/flash/flash_runner.md",
+    "artemis/agents/validator/failure_analyzer.md",
+    "artemis/agents/validator/target_disappeared_analyzer.md",
+    "artemis/agents/validator/pixel_target_disappeared_analyzer.md",
+    "artemis/agents/validator/pixel_safety_net.md",
+]
+
+# Backtick-quoted identifiers in scoped prompts that are not tools: parameter names and
+# note keys. Anything new landing here should be a conscious decision.
+NON_TOOL_IDENTIFIERS = frozenset({"analysis", "task_plan"})
+
+_TOOL_REF = re.compile(r"(?:`([a-z][a-z0-9_]{2,})`|\b([a-z][a-z0-9_]{2,})\()")
+
+
+def _scoped_prompt_sources() -> dict[str, str]:
+    """Collects all in-scope prompt texts, keyed by a short source label."""
+    sources: dict[str, str] = {}
+    for rel in SCOPED_PROMPT_FILES:
+        path = REPO_ROOT / rel
+        sources[path.name] = path.read_text(encoding="utf-8")
+
+    operator_json = REPO_ROOT / "artemis/agents/operator/operator.json"
+    for key, text in json.loads(operator_json.read_text(encoding="utf-8")).items():
+        sources[f"operator.json:{key}"] = text
+
+    # Only the prompt string constants from prompts.py -- scanning the module as text
+    # would pick up Python code (`len(`, `getattr(` ...).
+    from artemis.agents.operator import prompts as operator_prompts
+
+    for name in dir(operator_prompts):
+        value = getattr(operator_prompts, name)
+        if name.startswith("_") and isinstance(value, str) and len(value) > 80:
+            sources[f"prompts.py:{name}"] = value
+
+    return sources
+
+
+def _referenced_tools() -> dict[str, set[str]]:
+    """Returns {identifier: source labels} for every tool-shaped reference in scope."""
+    found: dict[str, set[str]] = {}
+    for label, text in _scoped_prompt_sources().items():
+        for match in _TOOL_REF.finditer(text):
+            name = match.group(1) or match.group(2)
+            found.setdefault(name, set()).add(label)
+    return found
+
+
+# --- Prompt <-> manifest invariants --------------------------------------------------
+
+
+def test_scan_finds_prompt_sources():
+    """The scan must cover all expected sources; silent scope loss would void the suite."""
+    sources = _scoped_prompt_sources()
+    assert "flash_runner.md" in sources
+    assert "operator.json:main_template" in sources
+    assert "operator.json:troubleshooter_template" in sources
+    assert any(label.startswith("prompts.py:") for label in sources)
+
+
+def test_every_prompt_tool_reference_is_classified():
+    """Every tool referenced by an in-scope prompt must be known to the manifest."""
+    unclassified = {
+        name: sorted(labels)
+        for name, labels in _referenced_tools().items()
+        if name not in ALL_KNOWN_TOOLS and name not in NON_TOOL_IDENTIFIERS
+    }
+    assert not unclassified, (
+        "Prompts reference tools the manifest does not classify. Add each to the "
+        f"appropriate set in artemis/mcp/action_manifest.py: {unclassified}"
+    )
+
+
+def test_required_actions_are_structurally_referenced():
+    """A REQUIRED action must actually appear in a prompt; otherwise demote it."""
+    referenced = set(_referenced_tools())
+    unreferenced = REQUIRED_ACTIONS - referenced
+    assert not unreferenced, (
+        f"REQUIRED_ACTIONS not referenced by any prompt: {sorted(unreferenced)}. "
+        "Required status exists only to protect structural prompt dependencies."
+    )
+
+
+def test_internal_actions_never_appear_in_prompts():
+    """INTERNAL actions are adapter plumbing and must stay invisible to every model."""
+    leaked = INTERNAL_ACTIONS & set(_referenced_tools())
+    assert not leaked, f"Internal actions leaked into prompts: {sorted(leaked)}"
+
+
+def test_manifest_sets_are_disjoint():
+    sets = {
+        "REQUIRED_ACTIONS": REQUIRED_ACTIONS,
+        "OPTIONAL_ACTIONS": OPTIONAL_ACTIONS,
+        "INTERNAL_ACTIONS": INTERNAL_ACTIONS,
+        "BACKEND_INDEPENDENT_TOOLS": BACKEND_INDEPENDENT_TOOLS,
+    }
+    names = list(sets)
+    for i, a in enumerate(names):
+        for b in names[i + 1 :]:
+            overlap = sets[a] & sets[b]
+            assert not overlap, f"{a} and {b} overlap: {sorted(overlap)}"
+
+
+# --- Actuator contract ---------------------------------------------------------------
+
+
+class _StubActuator:
+    """Minimal actuator test double with configurable capabilities and extensions."""
+
+    def __init__(self, caps=None, exts=None):
+        self._caps = frozenset(caps if caps is not None else DEVICE_ACTIONS)
+        self._exts = list(exts or [])
+
+    def capabilities(self):
+        return self._caps
+
+    def extensions(self):
+        return self._exts
+
+
+def _extension(**overrides) -> ExtensionTool:
+    async def _noop(**_kwargs):
+        return "ok"
+
+    defaults = dict(
+        name="calibrate_arm",
+        description=(
+            "Runs the robot arm's touch calibration sweep. Use before the first "
+            "physical action of a session, or after any missed tap."
+        ),
+        input_schema={"type": "object", "properties": {}},
+        handler=_noop,
+        targets=frozenset({"operator", "flash"}),
+    )
+    defaults.update(overrides)
+    return ExtensionTool(**defaults)
+
+
+def test_full_actuator_passes_validation():
+    validate_actuator(_StubActuator())
+
+
+def test_minimal_actuator_passes_validation():
+    """REQUIRED + INTERNAL alone is a legal backend; every optional action may be absent."""
+    validate_actuator(_StubActuator(caps=REQUIRED_ACTIONS | INTERNAL_ACTIONS))
+
+
+def test_missing_required_action_fails_fast():
+    caps = (DEVICE_ACTIONS - {"click_sequence"})
+    with pytest.raises(ActuatorContractError, match="click_sequence"):
+        validate_actuator(_StubActuator(caps=caps))
+
+
+def test_missing_internal_action_fails_fast():
+    caps = DEVICE_ACTIONS - {"observe_screen"}
+    with pytest.raises(ActuatorContractError, match="observe_screen"):
+        validate_actuator(_StubActuator(caps=caps))
+
+
+def test_unknown_capability_is_rejected():
+    """Backend-specific tools must go through extensions(), not capabilities()."""
+    with pytest.raises(ActuatorContractError, match="calibrate_arm"):
+        validate_actuator(_StubActuator(caps=DEVICE_ACTIONS | {"calibrate_arm"}))
+
+
+def test_extension_name_collision_fails_fast():
+    with pytest.raises(ActuatorContractError, match="collides"):
+        validate_actuator(_StubActuator(exts=[_extension(name="click")]))
+
+
+def test_duplicate_extension_names_fail_fast():
+    with pytest.raises(ActuatorContractError, match="more than once"):
+        validate_actuator(_StubActuator(exts=[_extension(), _extension()]))
+
+
+def test_extension_with_thin_description_is_rejected():
+    """Extensions get no prompt-level teaching; the description carries the contract."""
+    with pytest.raises(ActuatorContractError, match="description"):
+        validate_actuator(_StubActuator(exts=[_extension(description="Calibrates.")]))
+
+
+def test_extension_with_unknown_target_is_rejected():
+    with pytest.raises(ActuatorContractError, match="unknown agent role"):
+        validate_actuator(_StubActuator(exts=[_extension(targets=frozenset({"planner"}))]))
+
+
+# --- Surface derivation --------------------------------------------------------------
+
+
+def _declarations(*names: str) -> list[ToolDeclaration]:
+    return [
+        ToolDeclaration(name=n, description=f"{n} tool", parameters={"type": "object"})
+        for n in names
+    ]
+
+
+def test_available_device_actions_excludes_internal():
+    actions = available_device_actions(_StubActuator())
+    assert actions == REQUIRED_ACTIONS | OPTIONAL_ACTIONS
+    assert not actions & INTERNAL_ACTIONS
+
+
+def test_filter_drops_unimplemented_optional_actions():
+    actuator = _StubActuator(caps=DEVICE_ACTIONS - {"swipe", "manage_app"})
+    decls = _declarations("click", "swipe", "manage_app", "read_note")
+    kept = [d.name for d in filter_declarations(decls, actuator, agent="flash")]
+    assert kept == ["click", "read_note"]
+
+
+def test_filter_passes_through_unclassified_agent_tools():
+    """Agent-specific tools the manifest does not know must never be gated."""
+    actuator = _StubActuator(caps=REQUIRED_ACTIONS | INTERNAL_ACTIONS)
+    decls = _declarations("click_sequence", "reply_to_checker", "some_bespoke_tool")
+    kept = [d.name for d in filter_declarations(decls, actuator, agent="operator")]
+    assert kept == ["click_sequence", "reply_to_checker", "some_bespoke_tool"]
+
+
+def test_filter_appends_extensions_for_targeted_agents_only():
+    actuator = _StubActuator(exts=[_extension(targets=frozenset({"flash"}))])
+    decls = _declarations("click")
+
+    flash = [d.name for d in filter_declarations(decls, actuator, agent="flash")]
+    operator = [d.name for d in filter_declarations(decls, actuator, agent="operator")]
+
+    assert flash == ["click", "calibrate_arm"]
+    assert operator == ["click"]
+
+
+def test_filter_extension_declaration_shape():
+    """Extension declarations must be indistinguishable in shape from known ones."""
+    actuator = _StubActuator(exts=[_extension()])
+    decls = filter_declarations([], actuator, agent="operator")
+    assert len(decls) == 1
+    ext_decl = decls[0]
+    assert isinstance(ext_decl, ToolDeclaration)
+    assert ext_decl.name == "calibrate_arm"
+    assert ext_decl.parameters == {"type": "object", "properties": {}}
+
+
+def test_filter_rejects_unknown_agent_role():
+    with pytest.raises(ValueError, match="Unknown agent role"):
+        filter_declarations([], _StubActuator(), agent="planner")
+
+
+def test_all_agent_roles_are_covered():
+    assert AGENT_ROLES == {"operator", "flash", "failure_analyzer", "validator"}

tests/unit/mcp/test_action_server.py

@@ -0,0 +1,156 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""End-to-end tests of the unified action server over the in-memory transport."""
+
+import pytest
+
+from artemis.mcp.action_manifest import (
+    ActuatorContractError,
+    DEVICE_ACTIONS,
+    INTERNAL_ACTIONS,
+    REQUIRED_ACTIONS,
+    ExtensionTool,
+)
+from artemis.mcp.action_server import build_action_server
+from artemis.mcp.action_session import ActionSession
+from artemis.mcp.actuators import MockActuator
+
+pytestmark = pytest.mark.asyncio
+
+
+async def _session_for(actuator) -> ActionSession:
+    return await ActionSession(build_action_server(actuator)).start()
+
+
+async def test_click_end_to_end():
+    actuator = MockActuator(width=1000, height=2000)
+    session = await _session_for(actuator)
+    try:
+        res = await session.call("click", {"target": [500, 500]})
+        assert res.ok
+        assert res.message == "Clicked at [500, 500] (normalized) successfully."
+        assert actuator.action_history[-1]["action"] == "tap"
+        assert actuator.action_history[-1]["x"] == 500
+        assert actuator.action_history[-1]["y"] == 1000
+    finally:
+        await session.aclose()
+
+
+async def test_device_refusal_is_not_a_protocol_error():
+    """A failed action reaches the caller as ok=False, never as an exception."""
+    actuator = MockActuator()
+    session = await _session_for(actuator)
+    try:
+        res = await session.call("press_key", {"key": ""})
+        assert not res.ok
+        assert res.code.value == "INVALID_ARGS"
+        assert res.message == "Error executing key press ''."
+    finally:
+        await session.aclose()
+
+
+async def test_partial_actuator_hides_optional_tools():
+    """An unimplemented optional tool does not exist anywhere on the surface."""
+    minimal = MockActuator(capabilities=REQUIRED_ACTIONS | INTERNAL_ACTIONS)
+    session = await _session_for(minimal)
+    try:
+        listed = {t.name for t in (await session._session.list_tools()).tools}
+        assert "click_sequence" in listed
+        assert "observe_screen" in listed
+        for absent in ("click", "swipe", "manage_app", "wait_for_text", "open_link"):
+            assert absent not in listed
+    finally:
+        await session.aclose()
+
+
+async def test_missing_required_action_fails_at_build_time():
+    broken = MockActuator(capabilities=DEVICE_ACTIONS - {"click_sequence"})
+    with pytest.raises(ActuatorContractError, match="click_sequence"):
+        build_action_server(broken)
+
+
+async def test_extension_tool_is_served_and_callable():
+    async def calibrate(sweep_speed: int = 1) -> str:
+        return f"calibrated at speed {sweep_speed}"
+
+    ext = ExtensionTool(
+        name="calibrate_arm",
+        description=(
+            "Runs the robot arm's touch calibration sweep. Use before the first "
+            "physical action of a session, or after any missed tap."
+        ),
+        input_schema={"type": "object", "properties": {}},
+        handler=calibrate,
+        targets=frozenset({"flash"}),
+    )
+    actuator = MockActuator(extensions=[ext])
+    session = await _session_for(actuator)
+    try:
+        listed = {t.name for t in (await session._session.list_tools()).tools}
+        assert "calibrate_arm" in listed
+        result = await session.call_raw("calibrate_arm", {"sweep_speed": 3})
+        text = next(b.text for b in result.content if b.type == "text")
+        assert text == "calibrated at speed 3"
+    finally:
+        await session.aclose()
+
+
+async def test_extension_name_collision_fails_at_build_time():
+    async def bogus() -> str:
+        return "x"
+
+    ext = ExtensionTool(
+        name="click",
+        description="An extension improperly reusing a canonical tool name, which "
+        "must be rejected at build time.",
+        input_schema={"type": "object"},
+        handler=bogus,
+    )
+    with pytest.raises(ActuatorContractError, match="collides"):
+        build_action_server(MockActuator(extensions=[ext]))
+
+
+async def test_unknown_tool_raises_protocol_error():
+    session = await _session_for(MockActuator())
+    try:
+        with pytest.raises(RuntimeError, match="not_a_tool"):
+            await session.call_raw("not_a_tool", {})
+    finally:
+        await session.aclose()
+
+
+async def test_screenshot_and_hierarchy_helpers():
+    session = await _session_for(MockActuator(width=1000, height=2000))
+    try:
+        b64 = await session.screenshot_b64()
+        assert isinstance(b64, str) and len(b64) > 0
+        elements = await session.ui_hierarchy()
+        assert elements is not None
+    finally:
+        await session.aclose()
+
+
+async def test_structured_content_carries_real_status():
+    """The wire result exposes ok/code so no consumer ever sniffs substrings again."""
+    session = await _session_for(MockActuator())
+    try:
+        raw = await session.call_raw("click", {"target": [10, 10]})
+        sc = raw.structuredContent
+        assert sc["ok"] is True
+        assert sc["code"] == "OK"
+        assert sc["action"] == "click"
+        assert raw.isError is False
+    finally:
+        await session.aclose()

tests/unit/mcp/test_action_session.py

@@ -0,0 +1,188 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""ActionSession lifecycle tests, including the anyio same-task exit hazard."""
+
+import asyncio
+
+import pytest
+
+from artemis.mcp.action_server import build_action_server
+from artemis.mcp.action_session import ActionSession, get_action_session
+from artemis.mcp.actuators import MockActuator
+
+pytestmark = pytest.mark.asyncio
+
+
+async def test_start_and_close():
+    session = ActionSession(build_action_server(MockActuator()))
+    await session.start()
+    assert session.started
+    await session.aclose()
+    assert not session.started
+
+
+async def test_close_from_different_task():
+    """The regression guard for the anyio cancel-scope same-task rule.
+
+    The in-memory transport's task group is entered inside the owner task; closing
+    from any *other* task must not raise ``RuntimeError: Attempted to exit cancel
+    scope in a different task``.
+    """
+    session = ActionSession(build_action_server(MockActuator()))
+    await session.start()
+
+    async def _closer():
+        await session.aclose()
+
+    await asyncio.create_task(_closer())
+    assert not session.started
+
+
+async def test_caller_timeout_does_not_brick_the_session():
+    """Regression: cancelling a caller must never corrupt the shared transport.
+
+    Observed live on-device: ``asyncio.wait_for(session.ui_hierarchy(), 1.0)`` around
+    a slow hierarchy fetch cancelled ``call_tool`` mid-flight, corrupting the
+    in-memory streams -- every later call failed with an empty-message
+    ``BrokenResourceError`` and the server never received another request. The owner
+    request queue makes an abandoned caller harmless; this test pins that down.
+    """
+    actuator = MockActuator(width=1000, height=2000)
+
+    async def _slow_get_ui_elements():
+        await asyncio.sleep(2.0)
+        return []
+
+    actuator.get_ui_elements = _slow_get_ui_elements
+    session = await ActionSession(build_action_server(actuator)).start()
+    try:
+        with pytest.raises(asyncio.TimeoutError):
+            await asyncio.wait_for(session.ui_hierarchy(), timeout=0.1)
+
+        # The session must still be fully functional afterwards.
+        result = await session.call("click", {"target": [500, 500]})
+        assert result.ok
+        taps = [h for h in actuator.action_history if h["action"] == "tap"]
+        assert len(taps) == 1
+    finally:
+        await session.aclose()
+
+
+async def test_per_call_timeout_fires_server_side_and_session_survives():
+    """A per-call ``timeout`` runs inside the server tool, never on the transport.
+
+    mcp 1.29's ``read_timeout_seconds`` is NOT safe on the in-memory transport: a
+    late response to a timed-out request crashes the client receive loop
+    (``_handle_response`` sends into the request's already-closed response stream) --
+    observed live on-device as a session bricked after a single clean
+    ``McpError`` timeout. Server-side timeouts produce an ordinary error payload
+    and no late response, so the session stays healthy by construction.
+    """
+    actuator = MockActuator(width=1000, height=2000)
+
+    async def _slow_get_ui_elements():
+        await asyncio.sleep(2.0)
+        return []
+
+    actuator.get_ui_elements = _slow_get_ui_elements
+    session = await ActionSession(build_action_server(actuator)).start()
+    try:
+        with pytest.raises(RuntimeError, match="timed out"):
+            await session.ui_hierarchy(timeout=0.1)
+
+        result = await session.call("click", {"target": [500, 500]})
+        assert result.ok
+    finally:
+        await session.aclose()
+
+
+async def test_transport_death_retires_session_for_rebuild():
+    """A dead transport must flip ``started`` so get_action_session rebuilds.
+
+    Without this, one transport failure leaves the rest of a run failing on a
+    corpse (observed live: 24 minutes of empty-message ``ClosedResourceError``).
+    """
+    import anyio
+
+    session = await ActionSession(build_action_server(MockActuator())).start()
+    real_call_tool = session._session.call_tool
+
+    async def _dying_call_tool(name, args, **kw):
+        raise anyio.ClosedResourceError()
+
+    session._session.call_tool = _dying_call_tool
+    with pytest.raises(anyio.ClosedResourceError):
+        await session.call("click", {"target": [1, 1]})
+
+    # Owner loop retires; the session reports itself unusable. The owner task may
+    # finish with an exception group from the transport teardown -- aclose() is the
+    # API that swallows that, so here we just wait for `started` to flip.
+    for _ in range(50):
+        if not session.started:
+            break
+        await asyncio.sleep(0.1)
+    assert not session.started
+
+    class Ctx:
+        action_session = session
+
+    fresh = await get_action_session(Ctx(), actuator=MockActuator())
+    assert fresh is not session
+    assert fresh.started
+    await fresh.aclose()
+    del real_call_tool
+
+
+async def test_calls_are_serialized_by_the_lock():
+    """Two concurrent calls must not interleave on the single device."""
+    actuator = MockActuator(width=1000, height=2000)
+    session = await ActionSession(build_action_server(actuator)).start()
+    try:
+        await asyncio.gather(
+            session.call("click", {"target": [100, 100]}),
+            session.call("click", {"target": [900, 900]}),
+        )
+        taps = [h for h in actuator.action_history if h["action"] == "tap"]
+        assert len(taps) == 2
+    finally:
+        await session.aclose()
+
+
+async def test_call_before_start_raises():
+    session = ActionSession(build_action_server(MockActuator()))
+    with pytest.raises(RuntimeError, match="not started"):
+        await session.call("click", {"target": [1, 1]})
+
+
+async def test_double_start_is_idempotent():
+    session = ActionSession(build_action_server(MockActuator()))
+    await session.start()
+    owner = session._owner
+    await session.start()
+    assert session._owner is owner
+    await session.aclose()
+
+
+async def test_get_action_session_caches_on_ctx():
+    class Ctx:
+        action_session = None
+
+    ctx = Ctx()
+    actuator = MockActuator()
+    session = await get_action_session(ctx, actuator=actuator)
+    assert ctx.action_session is session
+    again = await get_action_session(ctx)
+    assert again is session
+    await session.aclose()

tests/unit/mcp/test_actuators.py

@@ -0,0 +1,146 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Actuator layer tests: coordinate conversion, message parity, driver dispatch."""
+
+import pytest
+
+from artemis.mcp.action_manifest import DEVICE_ACTIONS
+from artemis.mcp.action_types import ActionCode
+from artemis.mcp.actuators import Actuator, AdbActuator, MockActuator
+
+
+@pytest.fixture
+def actuator() -> MockActuator:
+    return MockActuator(width=1000, height=2000)
+
+
+def test_mock_actuator_satisfies_protocol(actuator):
+    assert isinstance(actuator, Actuator)
+    assert isinstance(actuator, AdbActuator)
+    assert actuator.capabilities() == DEVICE_ACTIONS
+    assert actuator.extensions() == []
+
+
+@pytest.mark.asyncio
+async def test_click_converts_normalized_to_pixels(actuator):
+    res = await actuator.click(500, 500)
+    assert res.ok and res.code is ActionCode.OK
+    # Historical wording is part of the contract: transcripts and traces assert on it.
+    assert res.message == "Clicked at [500, 500] (normalized) successfully."
+    assert res.normalized_coordinates == [500, 500]
+    assert actuator.action_history[-1] == {
+        "action": "tap",
+        "x": 500,
+        "y": 1000,
+        "times": 1,
+        "duration_ms": 100,
+    }
+
+
+@pytest.mark.asyncio
+async def test_click_sequence_taps_each_point(actuator):
+    res = await actuator.click_sequence([(100, 100), (900, 900)], delay_ms=1)
+    assert res.ok
+    assert res.message == (
+        "Sequence clicked successfully: Tapped at [100, 200]; Tapped at [900, 1800]"
+    )
+    taps = [h for h in actuator.action_history if h["action"] == "tap"]
+    assert [(t["x"], t["y"]) for t in taps] == [(100, 200), (900, 1800)]
+
+
+@pytest.mark.asyncio
+async def test_long_press_message_and_duration(actuator):
+    res = await actuator.long_press(250, 750, duration_ms=1500)
+    assert res.ok
+    assert res.message == (
+        "Long pressed at [250, 750] (normalized) for 1500ms successfully."
+    )
+    assert res.duration_ms == 1500
+
+
+@pytest.mark.asyncio
+async def test_swipe_reports_normalized_endpoints(actuator):
+    res = await actuator.swipe((500, 800), (500, 200), 400)
+    assert res.ok
+    assert res.message == "Swipe completed successfully. Swiped from [500, 800] to [500, 200]."
+    assert res.normalized_coordinates == [500, 800, 500, 200]
+
+
+@pytest.mark.asyncio
+async def test_press_key_forwards_unknown_keycode_to_driver(actuator):
+    # Arbitrary keycodes (KEYCODE_* names, numeric codes) pass through to the driver,
+    # matching the historical adb_server behavior of accepting any Android key event.
+    res = await actuator.press_key("KEYCODE_DPAD_DOWN")
+    assert res.ok
+    assert res.message == "Executed key press 'KEYCODE_DPAD_DOWN'."
+    assert actuator.action_history[-1]["action"] == "press_key"
+
+
+@pytest.mark.asyncio
+async def test_press_key_rejects_empty_key(actuator):
+    res = await actuator.press_key("")
+    assert not res.ok
+    assert res.code is ActionCode.INVALID_ARGS
+
+
+@pytest.mark.asyncio
+async def test_input_text_append_moves_cursor_and_preserves_text(actuator, monkeypatch):
+    monkeypatch.setattr("asyncio.sleep", _instant_sleep)
+    res = await actuator.input_text("hello", (500, 300), clear_exist=False)
+    assert res.ok
+    assert res.message == "Executed typing 'hello'."
+    actions = [h["action"] for h in actuator.action_history]
+    # Append semantics: focus tap, cursor-to-end (KEYCODE_MOVE_END), then type without
+    # clearing — matching the historical adb_server focus_and_input_text contract.
+    assert actions == ["tap", "press_key", "input_text"]
+    typed = actuator.action_history[-1]
+    assert typed["clear_existing"] is False
+    cursor = actuator.action_history[-2]
+    assert cursor["key"] == "123"
+
+
+@pytest.mark.asyncio
+async def test_input_text_clear_erases_then_types_without_reclearing(actuator, monkeypatch):
+    monkeypatch.setattr("asyncio.sleep", _instant_sleep)
+    res = await actuator.input_text("hello", (500, 300), clear_exist=True)
+    assert res.ok
+    actions = [h["action"] for h in actuator.action_history]
+    # The controller's full clear runs as a shell keyevent batch on this driver.
+    assert actions == ["tap", "execute_shell", "input_text"]
+    assert actuator.action_history[-1]["clear_existing"] is False
+
+
+async def _instant_sleep(_delay, *args, **kwargs):
+    return None
+
+
+@pytest.mark.asyncio
+async def test_wait_for_delay(actuator):
+    res = await actuator.wait_for_delay(1)
+    assert res.ok
+    assert res.message == "Waited for 1ms successfully."
+
+
+def test_partial_capabilities_are_reported():
+    partial = MockActuator(capabilities=frozenset({"click_sequence"}))
+    assert partial.capabilities() == frozenset({"click_sequence"})
+
+
+@pytest.mark.asyncio
+async def test_observation_primitives(actuator):
+    shot = await actuator.take_screenshot()
+    assert isinstance(shot, str) and len(shot) > 0
+    data = await actuator.get_screen_data()
+    assert data.width == 1000 and data.height == 2000

tests/unit/mcp/test_mcp_stdio_lifecycle.py

@@ -20,8 +20,10 @@ subprocess stdin isolation against pipe hijacking, and stdout purity.
 import io
 import json
 import os
+import queue
 import subprocess
 import sys
+import threading
 import time
 from unittest.mock import MagicMock, patch
 
@@ -34,6 +36,31 @@ from artemis.utils.logger import get_logger
 from mcp_server.utils import device_utils, env_utils
 
 
+def _readline_with_timeout(pipe, timeout: float) -> str | None:
+    """Read one line from a subprocess pipe with a timeout, portably.
+
+    select.select only supports sockets on Windows, so poll via a reader thread
+    instead of selecting on the pipe handle.
+    """
+    result: queue.Queue = queue.Queue()
+
+    def _reader():
+        try:
+            result.put(pipe.readline())
+        except Exception:
+            result.put(b"")
+
+    reader = threading.Thread(target=_reader, daemon=True)
+    reader.start()
+    try:
+        line = result.get(timeout=timeout)
+    except queue.Empty:
+        return None
+    if not line:
+        return None
+    return line.decode("utf-8").strip()
+
+
 def test_mcp_stdio_handshake_immediate_input():
     """Verify that MCP server over stdio responds to an immediate initialize request
 
@@ -51,6 +78,24 @@ def test_mcp_stdio_handshake_immediate_input():
             "PYTHONUNBUFFERED": "1",
             "PATH": os.environ.get("PATH", ""),
             "PYTHONPATH": project_root,
+            # Windows: the interpreter's socket stack (Winsock/_overlapped),
+            # Path.home(), and tempfile handling need these system variables.
+            **{
+                key: os.environ[key]
+                for key in (
+                    "SYSTEMROOT",
+                    "SYSTEMDRIVE",
+                    "WINDIR",
+                    "TEMP",
+                    "TMP",
+                    "USERPROFILE",
+                    "HOMEDRIVE",
+                    "HOMEPATH",
+                    "APPDATA",
+                    "LOCALAPPDATA",
+                )
+                if key in os.environ
+            },
         },
         cwd=project_root,
     )
@@ -71,15 +116,7 @@ def test_mcp_stdio_handshake_immediate_input():
         p.stdin.flush()
 
         # Read initialize response with a strict timeout
-        start = time.time()
-        init_resp_line = None
-        while time.time() - start < 6.0:
-            import select
-
-            r, _, _ = select.select([p.stdout], [], [], 0.2)
-            if r:
-                init_resp_line = p.stdout.readline().decode("utf-8").strip()
-                break
+        init_resp_line = _readline_with_timeout(p.stdout, 6.0)
 
         assert init_resp_line is not None, "MCP server failed to respond to initialize request within 6 seconds (deadlock detected)!"
         init_data = json.loads(init_resp_line)
@@ -93,15 +130,7 @@ def test_mcp_stdio_handshake_immediate_input():
         p.stdin.write(json.dumps(tools_req).encode("utf-8") + b"\n")
         p.stdin.flush()
 
-        tools_resp_line = None
-        start = time.time()
-        while time.time() - start < 4.0:
-            import select
-
-            r, _, _ = select.select([p.stdout], [], [], 0.2)
-            if r:
-                tools_resp_line = p.stdout.readline().decode("utf-8").strip()
-                break
+        tools_resp_line = _readline_with_timeout(p.stdout, 4.0)
 
         assert tools_resp_line is not None, "MCP server failed to respond to tools/list request!"
         tools_data = json.loads(tools_resp_line)

tests/unit/mcp/test_spawn_watchdog.py

@@ -0,0 +1,97 @@
+"""Tests for the spawn watchdog guarding mobile_run_task's standalone fallback."""
+
+import json
+import os
+from unittest.mock import patch
+
+from mcp_server.tools import task_runner as spawn_tool
+
+
+def _write_status(trace_dir: str, trace_id: str, status: str) -> None:
+    os.makedirs(trace_dir, exist_ok=True)
+    with open(os.path.join(trace_dir, "status.json"), "w", encoding="utf-8") as f:
+        json.dump({"trace_id": trace_id, "status": status}, f)
+
+
+def _patch_trace_dir(tmp_path):
+    return patch.object(spawn_tool.trace_store, "TRACES_DIR", str(tmp_path))
+
+
+def test_watchdog_passes_when_runner_creates_logs(tmp_path):
+    trace_id = "wd-boot-ok"
+    trace_dir = tmp_path / trace_id
+    _write_status(str(trace_dir), trace_id, "running")
+    (trace_dir / "stdout.log").write_text("booted", encoding="utf-8")
+
+    with _patch_trace_dir(tmp_path), patch.object(spawn_tool, "_kill_process_tree") as kill:
+        assert spawn_tool._watch_spawn(
+            trace_id, pid=999999, queue_ticket="t", conversation_id=None,
+            deadline_seconds=0.2, poll_interval=0.05,
+        )
+    kill.assert_not_called()
+
+
+def test_watchdog_skips_already_terminal_task(tmp_path):
+    trace_id = "wd-cancelled"
+    trace_dir = tmp_path / trace_id
+    _write_status(str(trace_dir), trace_id, "cancelled")
+
+    with _patch_trace_dir(tmp_path), patch.object(spawn_tool, "_kill_process_tree") as kill:
+        assert spawn_tool._watch_spawn(
+            trace_id, pid=999999, queue_ticket="t", conversation_id=None,
+            deadline_seconds=0.2, poll_interval=0.05,
+        )
+    kill.assert_not_called()
+
+
+def test_watchdog_kills_and_fails_hung_runner(tmp_path):
+    trace_id = "wd-hung"
+    trace_dir = tmp_path / trace_id
+    _write_status(str(trace_dir), trace_id, "running")
+
+    with (
+        _patch_trace_dir(tmp_path),
+        patch.object(spawn_tool, "_kill_process_tree") as kill,
+        patch.object(spawn_tool.DeviceExecutionLock, "cancel_reservation") as cancel,
+        patch.object(spawn_tool, "notify") as notifier,
+    ):
+        assert not spawn_tool._watch_spawn(
+            trace_id, pid=424242, queue_ticket="ticket-1", conversation_id="conv-1",
+            deadline_seconds=0.2, poll_interval=0.05,
+        )
+
+    kill.assert_called_once_with(424242)
+    cancel.assert_called_once_with("ticket-1")
+    notifier.assert_called_once()
+
+    with open(trace_dir / "status.json", encoding="utf-8") as f:
+        status = json.load(f)
+    assert status["status"] == "failed"
+    assert "no logs" in status.get("error", "")
+
+
+def test_watchdog_tolerates_logs_appearing_at_deadline(tmp_path):
+    """Logs that appear between the last poll and the deadline must not cause a kill."""
+    trace_id = "wd-late-boot"
+    trace_dir = tmp_path / trace_id
+    _write_status(str(trace_dir), trace_id, "running")
+
+    real_read_status = spawn_tool.trace_store.read_status
+    calls = {"n": 0}
+
+    def read_status_and_create_log(tid):
+        calls["n"] += 1
+        if calls["n"] == 1:
+            (trace_dir / "stderr.log").write_text("late boot", encoding="utf-8")
+        return real_read_status(tid)
+
+    with (
+        _patch_trace_dir(tmp_path),
+        patch.object(spawn_tool.trace_store, "read_status", side_effect=read_status_and_create_log),
+        patch.object(spawn_tool, "_kill_process_tree") as kill,
+    ):
+        assert spawn_tool._watch_spawn(
+            trace_id, pid=999999, queue_ticket="t", conversation_id=None,
+            deadline_seconds=0.15, poll_interval=0.2,
+        )
+    kill.assert_not_called()

tests/unit/mcp/test_task_reconcile.py

@@ -0,0 +1,133 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Regression tests for mobile_manage_task's state reconciliation.
+
+Guards the invariants restored after the reconcile rewrite:
+- a DB terminal verdict never overrides a status.json that already reached its
+  own terminal state (a completed task must keep its result),
+- except to correct a previously liveness-inferred failure,
+- and a task without a recorded pid (daemon dispatch) is never inferred dead.
+"""
+
+import sqlite3
+import time
+
+import pytest
+
+import mcp_server.tools.task_manager as task_manager
+from mcp_server.tools.task_manager import _LIVENESS_FAILURE_ERROR, _reconcile_task_state
+
+
+@pytest.fixture
+def no_persistence(monkeypatch):
+    """Keep reconciliation in-memory: no DB, no status writes, no lock queries."""
+    monkeypatch.setattr(task_manager, "_find_data_engine_db", lambda: None)
+    monkeypatch.setattr(task_manager, "_session_tracked_by_lock", lambda _tid: False)
+    monkeypatch.setattr(task_manager.trace_store, "write_status", lambda *_a, **_k: None)
+    monkeypatch.setattr(
+        task_manager.trace_store, "update_trace_status", lambda *_a, **_k: None
+    )
+    monkeypatch.setattr(task_manager, "notify", lambda *_a, **_k: None)
+
+
+def _db_with_session(tmp_path, trace_id: str, status: str, pid: int | None = 4242):
+    db_path = tmp_path / "artemis.db"
+    conn = sqlite3.connect(db_path)
+    conn.execute(
+        "CREATE TABLE sessions (session_id TEXT, status TEXT, pid INTEGER, start_time REAL)"
+    )
+    conn.execute(
+        "INSERT INTO sessions VALUES (?, ?, ?, ?)", (trace_id, status, pid, time.time())
+    )
+    conn.commit()
+    conn.close()
+    return str(db_path)
+
+
+@pytest.fixture
+def use_db(tmp_path, monkeypatch, no_persistence):
+    def _install(trace_id: str, status: str, pid: int | None = 4242):
+        db_path = _db_with_session(tmp_path, trace_id, status, pid)
+        monkeypatch.setattr(task_manager, "_find_data_engine_db", lambda: db_path)
+
+    return _install
+
+
+def test_db_failed_never_overrides_completed_status(use_db):
+    use_db("t1", "failed")
+    status_data = {"status": "completed", "result": "the answer", "pid": 111}
+
+    current_status, _pid, is_alive = _reconcile_task_state("t1", status_data)
+
+    assert current_status == "completed"
+    assert status_data["status"] == "completed"
+    assert status_data["result"] == "the answer"
+    assert is_alive is False
+
+
+def test_db_verdict_corrects_liveness_inferred_failure(use_db):
+    use_db("t2", "completed")
+    status_data = {"status": "failed", "error": _LIVENESS_FAILURE_ERROR, "pid": 111}
+
+    current_status, _pid, _is_alive = _reconcile_task_state("t2", status_data)
+
+    assert current_status == "completed"
+    assert status_data["error"] is None
+
+
+def test_db_never_overrides_user_cancellation(use_db):
+    use_db("t3", "completed")
+    status_data = {"status": "cancelled", "pid": 111}
+
+    current_status, _pid, _is_alive = _reconcile_task_state("t3", status_data)
+
+    assert current_status == "cancelled"
+
+
+def test_pidless_running_task_is_assumed_alive(no_persistence):
+    # Daemon dispatch writes no pid into status.json; liveness must not be
+    # inferred even long past the startup grace window.
+    status_data = {"status": "running", "start_time": time.time() - 3600}
+
+    current_status, _pid, is_alive = _reconcile_task_state("t4", status_data)
+
+    assert current_status == "running"
+    assert is_alive is True
+    assert status_data.get("error") is None
+
+
+def test_dead_pid_past_grace_is_marked_failed(no_persistence, monkeypatch):
+    monkeypatch.setattr(task_manager, "_pid_alive", lambda _pid: False)
+    status_data = {
+        "status": "running",
+        "pid": 99999,
+        "start_time": time.time() - 3600,
+    }
+
+    current_status, _pid, is_alive = _reconcile_task_state("t5", status_data)
+
+    assert current_status == "failed"
+    assert status_data["error"] == _LIVENESS_FAILURE_ERROR
+    assert is_alive is False
+
+
+def test_dead_pid_within_grace_is_assumed_alive(no_persistence, monkeypatch):
+    monkeypatch.setattr(task_manager, "_pid_alive", lambda _pid: False)
+    status_data = {"status": "running", "pid": 99999, "start_time": time.time()}
+
+    current_status, _pid, is_alive = _reconcile_task_state("t6", status_data)
+
+    assert current_status == "running"
+    assert is_alive is True

tests/unit/mcp/test_trace_store.py

@@ -14,6 +14,7 @@
 
 """Unit tests for MCP trace store."""
 
+import os
 import shutil
 import tempfile
 import uuid
@@ -80,6 +81,6 @@ def test_read_nonexistent_status(temp_trace_env):
 def test_trace_paths(temp_trace_env):
     trace_id = "test-paths-id"
     trace_dir = trace_store.get_trace_dir(trace_id)
-    assert trace_store.get_trace_notes_dir(trace_id) == f"{trace_dir}/notes"
-    assert trace_store.get_trace_stdout_log_path(trace_id) == f"{trace_dir}/stdout.log"
-    assert trace_store.get_trace_stderr_log_path(trace_id) == f"{trace_dir}/stderr.log"
+    assert trace_store.get_trace_notes_dir(trace_id) == os.path.join(trace_dir, "notes")
+    assert trace_store.get_trace_stdout_log_path(trace_id) == os.path.join(trace_dir, "stdout.log")
+    assert trace_store.get_trace_stderr_log_path(trace_id) == os.path.join(trace_dir, "stderr.log")

tests/unit/test_cli.py

@@ -222,7 +222,9 @@ def test_cli_mcp_install_all(tmp_path, monkeypatch):
     assert (tmp_path / ".gemini" / "rules" / "artemis.md").exists()
     assert (tmp_path / ".cursorrules").exists()
     assert (tmp_path / ".cursor" / "rules" / "artemis.mdc").exists()
-    assert (tmp_path / ".claude" / "CLAUDE.md").exists()
+    # Claude Code loads both CLAUDE.md and rules/*.md, so rules are installed
+    # only as the standalone rule file to avoid duplicated context.
+    assert not (tmp_path / ".claude" / "CLAUDE.md").exists()
     assert (tmp_path / ".claude" / "rules" / "artemis.md").exists()
     assert (tmp_path / ".codeium" / "windsurf" / "memories" / "global_rules.md").exists()
     assert (tmp_path / ".codeium" / "windsurf" / "rules" / "artemis.md").exists()
@@ -236,6 +238,69 @@ def test_cli_mcp_install_all(tmp_path, monkeypatch):
     assert (tmp_path / ".codex" / "AGENTS.md").exists()
 
 
+def test_cli_mcp_install_claude_migrates_legacy_claude_md(tmp_path, monkeypatch):
+    """Verify the claude target removes a previously injected CLAUDE.md block while preserving user content."""
+    monkeypatch.setattr("pathlib.Path.home", lambda: tmp_path)
+    monkeypatch.setenv("APPDATA", str(tmp_path / "AppData" / "Roaming"))
+    monkeypatch.setattr("mcp_server.utils.env_utils.get_project_root", lambda: str(tmp_path))
+
+    claude_dir = tmp_path / ".claude"
+    claude_dir.mkdir(parents=True)
+    claude_md = claude_dir / "CLAUDE.md"
+    claude_md.write_text(
+        "# My own instructions\n\n"
+        "<!-- BEGIN ARTEMIS MOBILE TESTING RULES -->\nold injected rules\n"
+        "<!-- END ARTEMIS MOBILE TESTING RULES -->\n",
+        encoding="utf-8",
+    )
+
+    result = runner.invoke(app, ["mcp", "--install", "claude"])
+    assert result.exit_code == 0
+
+    remaining = claude_md.read_text(encoding="utf-8")
+    assert "My own instructions" in remaining
+    assert "ARTEMIS MOBILE TESTING RULES" not in remaining
+    rule_file = claude_dir / "rules" / "artemis.md"
+    assert rule_file.exists()
+    assert "Mobile Testing Mindset" in rule_file.read_text(encoding="utf-8")
+
+
+def test_cli_mcp_install_claude_deletes_block_only_claude_md(tmp_path, monkeypatch):
+    """Verify a CLAUDE.md consisting solely of the injected block is deleted outright."""
+    monkeypatch.setattr("pathlib.Path.home", lambda: tmp_path)
+    monkeypatch.setenv("APPDATA", str(tmp_path / "AppData" / "Roaming"))
+    monkeypatch.setattr("mcp_server.utils.env_utils.get_project_root", lambda: str(tmp_path))
+
+    claude_dir = tmp_path / ".claude"
+    claude_dir.mkdir(parents=True)
+    claude_md = claude_dir / "CLAUDE.md"
+    claude_md.write_text(
+        "<!-- BEGIN ARTEMIS MOBILE TESTING RULES -->\nold injected rules\n"
+        "<!-- END ARTEMIS MOBILE TESTING RULES -->\n",
+        encoding="utf-8",
+    )
+
+    result = runner.invoke(app, ["mcp", "--install", "claude"])
+    assert result.exit_code == 0
+    assert not claude_md.exists()
+    assert (claude_dir / "rules" / "artemis.md").exists()
+
+
+def test_cli_mcp_install_claude_refuses_unparseable_claude_json(tmp_path, monkeypatch):
+    """Verify an unparseable ~/.claude.json is left untouched instead of being rewritten."""
+    monkeypatch.setattr("pathlib.Path.home", lambda: tmp_path)
+    monkeypatch.setenv("APPDATA", str(tmp_path / "AppData" / "Roaming"))
+    monkeypatch.setattr("mcp_server.utils.env_utils.get_project_root", lambda: str(tmp_path))
+
+    corrupt = "{ this is not json at all"
+    claude_json = tmp_path / ".claude.json"
+    claude_json.write_text(corrupt, encoding="utf-8")
+
+    result = runner.invoke(app, ["mcp", "--install", "claude"])
+    assert result.exit_code == 0
+    assert claude_json.read_text(encoding="utf-8") == corrupt
+
+
 def test_cli_mcp_install_codex_preserves_config_and_is_idempotent(tmp_path, monkeypatch):
     """Verify Codex TOML merging preserves other servers and updates only Artemis."""
     monkeypatch.setattr("pathlib.Path.home", lambda: tmp_path)