fix: make invalid source retries actionable

tests/test_agent_loop.py

@@ -59,6 +59,7 @@ def test_invalid_complete_python_source_is_detected_before_write() -> None:
     error = python_source_error({"path": "benchmark.py", "content": "# Report\n- O(n²)\n"})
     assert error is not None
     assert "invalid character" in error
+    assert "2: - O(n²)" in error
     assert python_source_error({"path": "benchmark.py", "content": "print('ok')\n"}) is None
 
 
@@ -900,6 +901,51 @@ async def test_bare_interactive_exec_is_blocked_before_registry(settings) -> Non
         await store.close()
 
 
+async def test_unchanged_invalid_python_write_is_not_revalidated(settings) -> None:
+    invalid_call = {
+        "choices": [
+            {
+                "message": {
+                    "role": "assistant",
+                    "tool_calls": [tool_call("1", "write_file", {"path": "broken.py", "content": "print('x'\n"})],
+                },
+                "finish_reason": "tool_calls",
+            }
+        ]
+    }
+    repeated_call = copy.deepcopy(invalid_call)
+    repeated_call["choices"][0]["message"]["tool_calls"][0]["id"] = "2"
+    final = {"choices": [{"message": {"role": "assistant", "content": "无法完成"}, "finish_reason": "stop"}]}
+    provider = ScriptedProvider([invalid_call, repeated_call, final])
+    registry = RecordingRegistry()
+    store = RuntimeStore(settings.database_url)
+    await store.initialize()
+
+    async def callback(event_type, payload):
+        return None
+
+    try:
+        answer = await AgentLoop(provider, registry, store, max_tool_output_chars=10_000).run(
+            spec=get_model_spec("work-light"),
+            messages=[{"role": "user", "content": "你好"}],
+            identity=UserIdentity("u1", "", "", "user"),
+            raw_user_jwt="jwt",
+            chat_id="invalid-repeat",
+            callback=callback,
+        )
+    finally:
+        await store.close()
+
+    assert answer == "无法完成"
+    assert registry.calls == []
+    repeated_result = next(
+        message["content"]
+        for message in provider.requests[2]["messages"]
+        if message.get("role") == "tool" and "unchanged write" in message.get("content", "")
+    )
+    assert "already failed validation" in repeated_result
+
+
 def test_tool_events_render_one_friendly_completed_card() -> None:
     assert tool_event_details("tool.started", {"name": "exec"}) is None
     rendered = tool_event_details(