refactor(remote_agent): single-pass unpaired-call guard

responses_api_agents/remote_agent/app.py

@@ -202,11 +202,17 @@ async def responses(
 
             # Execute only unpaired calls: a call the service already answered itself (matching
             # function_call_output in the same response) is its own internal-tool record and
-            # passes through into the trajectory untouched.
-            answered_call_ids = {o.call_id for o in output if o.type == "function_call_output"}
-            all_fn_calls: List[NeMoGymResponseFunctionToolCall] = [
-                o for o in output if o.type == "function_call" and o.call_id not in answered_call_ids
-            ]
+            # passes through into the trajectory untouched. Duplicate call_ids collapse to the
+            # last occurrence (call_id is unique by contract).
+            pending_calls: Dict[str, NeMoGymResponseFunctionToolCall] = {}
+            answered_call_ids = set()
+            for item in output:
+                if item.type == "function_call_output":
+                    answered_call_ids.add(item.call_id)
+                    pending_calls.pop(item.call_id, None)
+                elif item.type == "function_call" and item.call_id not in answered_call_ids:
+                    pending_calls[item.call_id] = item
+            all_fn_calls: List[NeMoGymResponseFunctionToolCall] = list(pending_calls.values())
             all_output_messages: List[NeMoGymResponseOutputMessage] = [
                 o for o in output if o.type == "message" and o.role == "assistant"
             ]

responses_api_agents/remote_agent/tests/test_app.py

@@ -410,6 +410,26 @@ async def test_paired_calls_pass_through_unexecuted(self, monkeypatch: pytest.Mo
         types = [o["type"] for o in dumped["response"]["output"]]
         assert types.count("function_call") == 2 and types.count("function_call_output") == 2
 
+    async def test_duplicate_call_ids_execute_once_with_last_arguments(self, monkeypatch: pytest.MonkeyPatch) -> None:
+        # call_id is unique by contract; a malformed duplicate collapses to the last occurrence.
+        service = scripted_service(
+            traj(
+                [
+                    fn_call("dup", "increment_counter", '{"count": 1}'),
+                    fn_call("dup", "increment_counter", '{"count": 3}'),
+                ]
+            ),
+            traj([msg("done")]),
+        )
+        agent, _, server_client = make_wired_agent(monkeypatch, service, tool_handler=self.counter_tool_handler)
+
+        result = await agent.run(make_request(), RemoteAgentRunRequest.model_validate(make_row(tools=_COUNTER_TOOLS)))
+
+        assert NG_FAILURE_CLASS_KEY not in result.model_dump()
+        tool_calls = [c for c in server_client.calls if c["url_path"] == "/increment_counter"]
+        assert len(tool_calls) == 1
+        assert tool_calls[0]["json"] == {"count": 3}
+
     async def test_unknown_tool_error_fed_back_not_raised(self, monkeypatch: pytest.MonkeyPatch) -> None:
         service = scripted_service(
             traj([fn_call("c1", "web_search", "{}")]),  # unpaired ask for a tool the env doesn't serve