feat: improve task execution, verification and packaging

Add execution incidents, action bursts and shared Flash history.

Expose verification and Explorer settings with streamed check results.

Support graceful cancellation, recording recovery and bundled UI resources.

Add CI quality checks and clean up comments and documentation.

artemis/agents/checker/checker.py

@@ -39,10 +39,10 @@ from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Any, Literal
 
-from langchain_core.messages import HumanMessage, SystemMessage, ToolMessage
+from langchain_core.messages import AIMessage, HumanMessage, SystemMessage, ToolMessage
 from langchain_core.tools import BaseTool, tool
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ValidationError
 
 from artemis.constants import CHECKER_MAX_ITERATIONS
 from artemis.context import ArtemisContext
@@ -416,14 +416,23 @@ def _format_check_items(check_items: list) -> str:
 
 async def _structured_report(llm, messages) -> CheckReport:
     structured_llm = llm.with_structured_output(CheckReport)
+    # A conversation must end with a user turn: Gemini rejects requests whose
+    # last message is the model's own answer ("Requests ending with a model
+    # turn are not supported"), which is exactly the state after the loop's
+    # final tool-free reply. Nudge with an explicit verdict request instead.
+    if messages and isinstance(messages[-1], AIMessage):
+        messages = [
+            *messages,
+            HumanMessage(content="Now provide your structured verdict report."),
+        ]
     result = await invoke_llm_with_timeout_message(structured_llm.ainvoke(messages))
     if isinstance(result, CheckReport):
         return result
     if isinstance(result, dict):
         try:
             return CheckReport.model_validate(result)
-        except Exception:
-            pass
+        except ValidationError as exc:
+            logger.debug("Structured verdict dict failed CheckReport validation: %s", exc)
     return CheckReport(verdicts=[])
 
 
@@ -502,6 +511,17 @@ async def _run_check_loop(
                 shot = _load_step_screenshot(
                     ctx, int(args.get("step_no", -1)), str(args.get("which", "pre"))
                 )
+                # The image is spliced in below; invoking the (traced) tool as
+                # well records the lookup as a tool trace so the timeline shows
+                # it in order with the rest of the check.
+                screenshot_tool = next((t for t in traced_tools if t.name == tool_name), None)
+                if screenshot_tool is not None:
+                    try:
+                        await invoke_tool_with_injection(
+                            tool=screenshot_tool, args=args, tool_call_id=tc["id"]
+                        )
+                    except Exception as e:
+                        logger.debug(f"Screenshot lookup trace not recorded: {e}")
                 messages.append(ToolMessage(tool_call_id=tc["id"], content=shot.description))
                 if shot.image_b64:
                     messages.append(
@@ -547,6 +567,16 @@ async def _run_check_loop(
 # --- Entry points --------------------------------------------------------------------
 
 
+def _announce(ctx: ArtemisContext, **kwargs) -> None:
+    """Lazy bridge to the checkpoint bus (avoids an import cycle at module load)."""
+    try:
+        from artemis.graph.checkpoints import announce_checker_attempt
+
+        announce_checker_attempt(ctx, **kwargs)
+    except Exception as e:
+        logger.debug(f"Checker attempt announcement skipped: {e}")
+
+
 @trace(type="agent", name="checker")
 async def run_checkpoint_check(
     ctx: ArtemisContext,
@@ -554,6 +584,7 @@ async def run_checkpoint_check(
     anchor,
     goal: str,
     subgoal_text: str,
+    attempt_id: str | None = None,
 ) -> CheckReport:
     """Audits one completed subgoal's on_complete check items.
 
@@ -563,6 +594,15 @@ async def run_checkpoint_check(
     """
     items = list(check_items)
     logger.info(f"Starting checkpoint check for '{subgoal_text}' ({len(items)} item(s))")
+    _announce(
+        ctx,
+        attempt_id=attempt_id,
+        phase="checkpoint",
+        checkpoint_id=attempt_id.split("#", 1)[0] if attempt_id else "",
+        subgoal_text=subgoal_text,
+        anchor_step_id=getattr(anchor, "anchor_step_id", None),
+        check_items=items,
+    )
     prompts = _load_prompts()
     tools = build_checker_tools(ctx, "checkpoint")
     probe_registered = any(t.name == "probe_device" for t in tools)
@@ -655,11 +695,21 @@ async def run_final_check(
     plan_text: str,
     ledger: list[dict],
     check_items,
+    attempt_id: str | None = None,
 ) -> CheckReport:
     """Final review at task exit: audits the user's original goal and all
     declared check items, with the final screen state available."""
     items = list(check_items)
     logger.info(f"Starting final check ({len(items)} declared item(s))")
+    _announce(
+        ctx,
+        attempt_id=attempt_id,
+        phase="final",
+        checkpoint_id="final",
+        subgoal_text="Final review against the user's original goal",
+        anchor_step_id=None,
+        check_items=items,
+    )
     prompts = _load_prompts()
     tools = build_checker_tools(ctx, "final")
     probe_registered = any(t.name == "probe_device" for t in tools)