feat(plugins): add source-aware evidence and recording timelines

examples/plugins/evidence-demo/server.py

@@ -0,0 +1,64 @@
+"""Minimal task-owned attachment server. Run through ARTEMIS, not as a shell tool."""
+
+import hashlib
+import os
+from pathlib import Path
+import time
+import uuid
+
+from mcp.server.fastmcp import FastMCP
+from mcp.types import CallToolResult, TextContent, ToolAnnotations
+
+mcp = FastMCP("evidence-demo")
+
+
+@mcp.tool(
+    annotations=ToolAnnotations(readOnlyHint=False, destructiveHint=False, idempotentHint=False)
+)
+def write_note(text: str) -> CallToolResult:
+    """Save at most 16 KiB of user-requested text as a new task attachment."""
+    encoded = text.encode("utf-8")
+    root = os.environ.get("ARTEMIS_ARTIFACTS_DIR")
+    if not root or len(encoded) > 16384:
+        return CallToolResult(
+            isError=True,
+            content=[TextContent(type="text", text="任务目录缺失或内容超过 16 KiB；未写文件。")],
+            structuredContent={
+                "artemis": {
+                    "version": 1,
+                    "execution": "not_started",
+                    "side_effect": "none",
+                    "error_code": "invalid_input",
+                    "retryable": False,
+                }
+            },
+        )
+    directory = Path(root)
+    directory.mkdir(parents=True, exist_ok=True)
+    name = f"note-{uuid.uuid4().hex}.txt"
+    path = directory / name
+    with path.open("xb") as handle:
+        handle.write(encoded)
+    digest = hashlib.sha256(path.read_bytes()).hexdigest()
+    return CallToolResult(
+        content=[TextContent(type="text", text=f"已保存并读回校验：{name}")],
+        structuredContent={
+            "artemis": {
+                "version": 1,
+                "execution": "completed",
+                "side_effect": "confirmed",
+                "retryable": False,
+                "source": {
+                    "kind": "file",
+                    "target_id": "task-artifacts",
+                    "label": "任务文件",
+                    "captured_at": time.time(),
+                },
+                "attachments": [{"name": name, "sha256": digest, "media_type": "text/plain"}],
+            }
+        },
+    )
+
+
+if __name__ == "__main__":
+    mcp.run(transport="stdio")