Model tries to call unknown function multi_tool_use.parallel

I’m sorry to hear that. Properly using the tool that is a wrapper, where the output of the other “functions” tool should instead be placed in a new described tool for parallel tool calls, is a challenge to AI comprehension. Even challenging for a human to read and play along at home when seeing the instructions of the parallel function call wrapper - which has the name in the topic title.

What can you do?

  • disable parallel tool calls with API parameter to do so, removing the additional tool;
  • decrease temperature or top_p, and put both into use;
  • if on gpt-4o, you can use structured outputs strict specification if compatible with the function;
  • you can revert to functions, which for the AI comprehension side is pretty similar, no parallel functions.
  • use a capable AI model, and ask OpenAI (fruitlessly for a year and a half) to stop providing unstable models of the same name which they stealth modify.