When streaming, using tool_choice: {"type": "function", "function": {"name": "get_weather"}} just doesn’t work with o3-mini and the model decides to just stream some arbitrary attempt of the function in chunk.choices[0].delta.content instead of the tool_calls field. Replicable in the playground (no…

O3-mini `tool_choice` not working during streaming? Also `parallel_tool_calls` just doesn't work with this model?

coleman February 19, 2025, 5:23pm 2

Topic		Replies	Views
Responses API allowed_tools tool_choice parameter now failing for GPT-5 Bugs	17	1450	September 18, 2025
Parallel Tool-use Documentation for API models? API gpt-4 , api , o3	2	933	July 1, 2025
Setting parallel_tool_calls = False doesn't work in the Chat completions API Bugs	3	1468	December 30, 2024
Different behavior in streaming function calling Bugs	5	724	March 18, 2024
Giving a value to "tool_choice" no longer allows functions to be called in parallel Bugs api , function-calling , tool-choice , gpt-0125 , gpt-1106	3	3619	May 14, 2024