Reproduction steps

1. Start Zed.
2. Start new Zed agent thread.
3. Start with GPT 5.4
4. Switch model to Claude (Sonnet/Opus) in the middle.
5. Error (see screenshots)

Current vs. Expected behavior

I used to be able to do this. Maybe it's not possible anymore in the v1 release.

Zed version and system specs

Zed 1.1.7
Commit: c17f25c
Version: 1.1.7+stable.268.c17f25cd782edffab64b7c4167abfa44f865b125

Attach Zed log file

Relevant Zed settings

Relevant Keymap

(for AI issues) Model provider details

  {
    "provider": "copilot_chat",
    "model": "gpt-5.4",
    "enable_thinking": true,
    "effort": "high",
  },
  {
    "provider": "copilot_chat",
    "model": "claude-sonnet-4.6",
    "enable_thinking": true,
    "effort": "medium",
  },

If you are using WSL on Windows, what flavor of Linux are you using?

None