Claude Opus 4.7 can be selected in Copilot Chat Agent mode, but requests fail with "Language model unavailable" on Copilot Pro+

[Nexulo]

• VS Code Extension: GitHub Copilot 1.388.0
• VS Code Version: Version: 1.116.0 Commit: 560a9db Date: 2026-04-15T00:28:13Z (2 days ago)
• OS Version: macOS 26.4.1 (25E253)

Claude Opus 4.7 appears as a selectable model in VS Code GitHub Copilot Chat (Agent mode), but every request fails with Language model unavailable.

I am on an active GitHub Copilot Pro+ subscription, so I would expect the model to work if it is shown as selectable.

Steps to reproduce:

1. Open VS Code.
2. Open Copilot Chat.
3. Switch to Agent mode.
4. Select Claude Opus 4.7.
5. Send any prompt.

Expected:
The request is processed with Claude Opus 4.7.

Actual:
The request fails immediately with Language model unavailable.

[vs-code-engineering]

This issue is a duplicate of #253137. Please refer to that issue for updates and discussions. Feel free to open a new issue if you think this is a different problem.

[Nexulo]

[solution]
For anyone else who ran into this issue:
After restarting to install the VS Code update, I had to completely close VS Code and restart it, and then it worked.