litellm - 💡(How to fix) Fix [Bug]: v1.83.7 regression - tool_call function.arguments lost during OpenAI→Anthropic response conversion

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What happened?

Setup: Claude Code → Anthropic protocol → litellm proxy → OpenAI protocol → glm-5.1

What happens: Model returns correct function.arguments (e.g. '{"file_path": "test.py"}'), but after litellm converts the response to Anthropic format, the tool_use.input becomes {} (empty dict).

Evidence from logs:

OpenAI response (correct): arguments='{"file_path": "D:\python-code\test\app.py"}' Anthropic response sent to client (broken): input: {} Next request from Claude Code includes the broken input: {} Regression: v1.79.1 does NOT have this issue. v1.83.7 does.

Related code changes in v1.83.7:

New _remove_thought_signatures_from_messages function with model_dump() calls New _process_assistant_message_tool_calls with model_dump() on tool_call Pydantic models from future import annotations added to utils.py

Steps to Reproduce

Relevant log output

What part of LiteLLM is this about?

No response

What LiteLLM version are you on ?

v1.83.7-stable

Twitter / LinkedIn details

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