GPT-6 Astra tool calling requires the Responses API

GPT-6 Astra drops custom temperature, top_p and logprobs, and tool calling requires the Responses API rather than Chat Completions.

Who is affected:: Apps moving to Astra that use tools through Chat Completions or set sampling parameters.
What to do:: Follow the Responses migration guide before switching tool-using apps to Astra.

Source

"Tool calling requires the Responses API."

OpenAI API changelog

Published Sep 3, 2026

Modelpeers tracks changes to AI agents and models, each from its source. Follow GPT-6 Astra to get a weekly email when it changes.