Add server tool timeout protection

engine/core/duplex_pipeline.py

@@ -58,6 +58,7 @@ class DuplexPipeline:
     _SENTENCE_CLOSERS = frozenset({'"', "'", "”", "’", ")", "]", "}", "）", "】", "」", "』", "》"})
     _MIN_SPLIT_SPOKEN_CHARS = 6
     _TOOL_WAIT_TIMEOUT_SECONDS = 15.0
+    _SERVER_TOOL_TIMEOUT_SECONDS = 15.0
     _DEFAULT_TOOL_SCHEMAS: Dict[str, Dict[str, Any]] = {
         "search": {
             "name": "search",
@@ -984,7 +985,18 @@ class DuplexPipeline:
                         tool_results.append(result)
                         continue
 
-                    result = await execute_server_tool(call)
+                    try:
+                        result = await asyncio.wait_for(
+                            execute_server_tool(call),
+                            timeout=self._SERVER_TOOL_TIMEOUT_SECONDS,
+                        )
+                    except asyncio.TimeoutError:
+                        result = {
+                            "tool_call_id": call_id,
+                            "name": self._tool_name(call) or "unknown_tool",
+                            "output": {"message": "server tool timeout"},
+                            "status": {"code": 504, "message": "server_tool_timeout"},
+                        }
                     await self._emit_tool_result(result, source="server")
                     tool_results.append(result)
 

engine/tests/test_tool_call_flow.py

@@ -252,3 +252,50 @@ async def test_server_calculator_emits_tool_result(monkeypatch):
     payload = tool_results[-1].get("result", {})
     assert payload.get("status", {}).get("code") == 200
     assert payload.get("output", {}).get("result") == 3
+
+
+@pytest.mark.asyncio
+async def test_server_tool_timeout_emits_504_and_continues(monkeypatch):
+    async def _slow_execute(_call):
+        await asyncio.sleep(0.05)
+        return {
+            "tool_call_id": "call_slow",
+            "name": "weather",
+            "output": {"ok": True},
+            "status": {"code": 200, "message": "ok"},
+        }
+
+    monkeypatch.setattr("core.duplex_pipeline.execute_server_tool", _slow_execute)
+
+    pipeline, events = _build_pipeline(
+        monkeypatch,
+        [
+            [
+                LLMStreamEvent(
+                    type="tool_call",
+                    tool_call={
+                        "id": "call_slow",
+                        "executor": "server",
+                        "type": "function",
+                        "function": {"name": "weather", "arguments": "{\"city\":\"hz\"}"},
+                    },
+                ),
+                LLMStreamEvent(type="done"),
+            ],
+            [
+                LLMStreamEvent(type="text_delta", text="timeout fallback."),
+                LLMStreamEvent(type="done"),
+            ],
+        ],
+    )
+    pipeline._SERVER_TOOL_TIMEOUT_SECONDS = 0.01
+
+    await pipeline._handle_turn("weather?")
+
+    tool_results = [e for e in events if e.get("type") == "assistant.tool_result"]
+    assert tool_results
+    payload = tool_results[-1].get("result", {})
+    assert payload.get("status", {}).get("code") == 504
+    finals = [e for e in events if e.get("type") == "assistant.response.final"]
+    assert finals
+    assert "timeout fallback" in finals[-1].get("text", "")