DeepSeek/Kimi reasoning field promotion bug fixes

Fixes on record

Merged to main. A stamp counts the issues a fix is linked to.

• #15478 fix: DeepSeek/Kimi thinking mode requires reasoning_content on ALL assistant messages

  merged to main

  files: run_agent.py, tests/run_agent/test_deepseek_reasoning_content_echo.py

  Show the diff

  • run_agent.py

    @@ -7785,7 +7785,17 @@ def _copy_reasoning_content_for_api(self, source_msg: dict, api_msg: dict) -> No
                 api_msg["reasoning_content"] = normalized_reasoning
                 return
     
    -        # 4. reasoning_content was present but not a string (e.g. None after
    +        # 4. DeepSeek / Kimi thinking mode: all assistant messages need
    +        # reasoning_content. Inject "" to satisfy the provider's requirement
    +        # when no explicit reasoning content is present.
    +        if (
    +            self._needs_kimi_tool_reasoning()
    +            or self._needs_deepseek_tool_reasoning()
    +        ):
    +            api_msg["reasoning_content"] = ""
    +            return
    +
    +        # 5. reasoning_content was present but not a string (e.g. None after
             # context compaction).  Don't pass null to the API.
             api_msg.pop("reasoning_content", None)
     

  • tests/run_agent/test_deepseek_reasoning_content_echo.py

    @@ -88,13 +88,13 @@ def test_deepseek_tool_call_poisoned_history_gets_empty_string(self) -> None:
             agent._copy_reasoning_content_for_api(source, api_msg)
             assert api_msg.get("reasoning_content") == ""
     
    -    def test_deepseek_assistant_no_tool_call_left_alone(self) -> None:
    -        """Plain assistant turns without tool_calls don't get padded."""
    +    def test_deepseek_assistant_no_tool_call_gets_padded(self) -> None:
    +        """DeepSeek thinking mode pads ALL assistant turns, even without tool_calls."""
             agent = _make_agent(provider="deepseek", model="deepseek-v4-flash")
             source = {"role": "assistant", "content": "hello"}
             api_msg: dict = {}
             agent._copy_reasoning_content_for_api(source, api_msg)
    -        assert "reasoning_content" not in api_msg
    +        assert api_msg.get("reasoning_content") == ""
     
         def test_deepseek_explicit_reasoning_content_preserved(self) -> None:
             """When reasoning_content is already set, it's copied verbatim."""

• #16097 fix(run_agent): restore reasoning field promotion on DeepSeek/Kimi tool-call turns (salvage #15883)

  merged to main

  files: run_agent.py, scripts/release.py