Stabilize product data export flow

src/agent_runtime.py

@@ -832,8 +832,15 @@ class LocalCodingAgent:
                             return result
                         # fall through to the normal tool-call branch below
                 # normal error path if not recovered
+                final_output = str(exc)
+                session.append_assistant(
+                    final_output,
+                    message_id=f'assistant_{len(session.messages)}',
+                    stop_reason='backend_error',
+                )
+                _append_final_text_stream_events(stream_events, final_output)
                 result = AgentRunResult(
-                    final_output=str(exc),
+                    final_output=final_output,
                     turns=max(turn_index - 1, 0),
                     tool_calls=tool_calls,
                     transcript=session.transcript(),
@@ -1535,15 +1542,42 @@ class LocalCodingAgent:
             usage=usage,
         )
         assistant_message = session.messages[assistant_index]
+        try:
+            parsed_tool_calls = self._tool_calls_from_message(assistant_message.tool_calls)
+        except OpenAICompatError:
+            self._scrub_malformed_assistant_tool_calls(session, assistant_index)
+            raise
         turn = AssistantTurn(
             content=assistant_message.content,
-            tool_calls=self._tool_calls_from_message(assistant_message.tool_calls),
+            tool_calls=parsed_tool_calls,
             finish_reason=finish_reason,
             raw_message=assistant_message.to_openai_message(),
             usage=usage,
         )
         return turn, tuple(events)
 
+    def _scrub_malformed_assistant_tool_calls(
+        self,
+        session: AgentSessionState,
+        assistant_index: int,
+    ) -> None:
+        message = session.messages[assistant_index]
+        filtered_blocks = tuple(
+            block
+            for block in message.blocks
+            if block.get('type') not in {'tool_use', 'tool_call'}
+        )
+        session.messages[assistant_index] = replace(
+            message,
+            tool_calls=(),
+            blocks=filtered_blocks,
+            stop_reason='malformed_tool_arguments',
+            metadata={
+                **message.metadata,
+                'malformed_tool_arguments': True,
+            },
+        )
+
     def _tool_calls_from_message(
         self,
         tool_calls: tuple[dict[str, object], ...],
@@ -1558,7 +1592,18 @@ class LocalCodingAgent:
                 continue
             raw_arguments = function_block.get('arguments', '')
             if isinstance(raw_arguments, str) and raw_arguments.strip():
-                arguments = json.loads(raw_arguments)
+                try:
+                    arguments = json.loads(raw_arguments)
+                except json.JSONDecodeError as exc:
+                    preview = raw_arguments[:240].replace('\n', '\\n')
+                    raise OpenAICompatError(
+                        '模型返回的工具参数不是合法 JSON，已停止本轮以避免执行错误工具。'
+                        f'工具：{name}；位置：line {exc.lineno} column {exc.colno}；'
+                        f'原因：{exc.msg}；参数片段：{preview!r}。'
+                        '请回复“继续”，我会要求模型重新生成合法 JSON 参数；'
+                        '对于大段 dataset draft，应分批或使用 draft_path/records_path，'
+                        '不要把大量带引号的文本一次性塞进工具参数。'
+                    ) from exc
                 if not isinstance(arguments, dict):
                     raise OpenAICompatError(
                         f'Tool arguments must decode to an object, got {type(arguments).__name__}'