[BUG] Cowork 3P Gateway — claude-opus-4.7 fails with "thinking.type.enabled is not supported"

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Product: Claude Desktop — Cowork on 3P (Gateway mode)
Gateway: GitHub Copilot (https://api.githubcopilot.com)
When selecting claude-opus-4.7 in the Cowork model picker (3P Gateway), every request fails with:
API Error: 400 {"type":"error","error":{"type":"invalid_request_error",
"message":"\"thinking.type.enabled\" is not supported for this model.
Use \"thinking.type.adaptive\" and \"output_config.effort\" to control thinking behavior."}}
Cowork sends thinking.type: "enabled" but Opus 4.7 requires thinking.type: "adaptive" + output_config.effort. Older models (Opus 4.6, Sonnet 4.6) work fine.
Related: #52526 (model picker display name truncation — same setup)

What Should Happen?

Cowork should detect the model's required thinking configuration and send the correct parameters:

• For models that support thinking.type: "enabled" → send as-is
• For models that require thinking.type: "adaptive" (e.g. Opus 4.7) → send thinking.type: "adaptive" + output_config.effort

Error Messages/Logs

Steps to Reproduce

1. Configure 3P Gateway with GitHub Copilot
2. Add claude-opus-4.7 to inferenceModels
3. Select it in the Cowork picker
4. Send any message → 400 error

Workaround: Use claude-opus-4.6 instead.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.3883.0 (93ff6c) 2026-04-21T17:24:01.000Z

Platform

Other

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_