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gpt-5.6 in combination with azure fails because of reasoning effort #40257
Description
Related to #26222
Description
This causes requests to fail for setups where gpt-5.56is routed through /v1/chat/completions, especially with Azure/OpenAI-compatible gateways.
Error:
Bad Request: Error code: 400 - Function tools with reasoning_effort are not supported for gpt-5.6-sol in /v1/chat/completions. Please use /v1/responses instead.
The issue is caused by this condition also matching gpt-5.6. Only gpt-5-chat and gpt-5.5 is currently excluded. gpt-5.6 should also be excluded here.
Plugins
None
OpenCode version
v1.18.6
Steps to reproduce
- Configure OpenCode with an Azure/OpenAI-compatible provider using
gpt-5.5. - Route requests through
/v1/chat/completions. - Start a new OpenCode session with
gpt-5.5. - Send any prompt.
- The request fails because OpenCode automatically includes
reasoningEffort: "medium".
Expected: OpenCode should not send reasoningEffort for gpt-5.6 when using chat completions.
Actual: The request fails with a 400 error.
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Operating System
macOS 26.4.1
Terminal
Mac Terminal
Plugins
No response
OpenCode version
No response
Steps to reproduce
No response
Screenshot and/or share link
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Operating System
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Terminal
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github-actions commentedon Aug 3, 2026
This issue might be a duplicate of existing issues. Please check:
model.capabilities.reasoning, which covers this class of failure.If your issue is specifically about
gpt-5.6not being excluded from thereasoningEffortinjection (likegpt-5-chatandgpt-5.5already are), it may be worth referencing #35732 or #34282 directly, or confirming whether those issues cover your case.