Handling LDP Agent incorrectly giving Message

[jamesbraza]

We are seeing crashes due to GPT 5.2 occasionally giving a Message over a ToolRequestMessage. Arguably we should fix this in LDP, but for now we can react here too:

Traceback (most recent call last):
  File "/app/.venv/lib/python3.13/site-packages/ldp/alg/rollout.py", line 61, in reraise_exc_as
    yield
  File "/app/.venv/lib/python3.13/site-packages/ldp/alg/rollout.py", line 453, in _take_step
    next_obs, reward, done, trunc = await env.step(action.value)
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/paperqa_server/agents/env.py", line 1100, in step
    messages, reward, done, truncated = await super().step(action)
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/aviary/envs/labbench/env.py", line 146, in step
    messages, reward, done, truncated = await super().step(action)
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/paperqa/agents/env.py", line 312, in step
    self.state.record_action(action)
    ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/paperqa/agents/tools.py", line 85, in record_action
    self.session.tool_history.append([tc.function.name for tc in action.tool_calls])
                                                                 ^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/pydantic/main.py", line 1026, in __getattr__
    raise AttributeError(f'{type(self).__name__!r} object has no attribute {item!r}')
AttributeError: 'Message' object has no attribute 'tool_calls'

[dosubot]

Related Documentation

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[Copilot]

Pull request overview

This PR addresses a critical bug where GPT 5.2 occasionally returns a plain Message object instead of the expected ToolRequestMessage, causing crashes when the code tries to access the tool_calls attribute. The fix implements defensive programming by handling both message types gracefully in the record_action method and the environment's step method.

Changes:

• Modified record_action method signature to accept both Message and ToolRequestMessage types
• Added runtime type checking in record_action to only append tool history when a ToolRequestMessage is received
• Added type guard in environment's step method to return a helpful error message when receiving a plain Message

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
src/paperqa/agents/tools.py	Updated record_action signature to handle both Message and ToolRequestMessage, with conditional tool history tracking
src/paperqa/agents/env.py	Added type guard in step method to gracefully handle plain Message objects and return error response

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