### Describe the bug When running /compact in Copilot CLI after switching from the Claude Opus 4.6 model to the GPT-4.1 model, I receive the following error: - If /compact is run automatically by Copilot: - Execution failed: CAPIError: 400 Unrecognized request argument supplied: reasoning_effort (Request ID: `ID`) - If /compact is run manually by me: - Compaction Failed: CAPIError: 400 Unrecognized request argument supplied: reasoning_effort ### Affected version 1.0.19 ### Steps to reproduce the behavior 1. Start a session using Claude Opus 4.6 (or any model supporting reasoning_effort). 2. Switch to GPT-4.1. 3. Run /compact (either automatically or manually). 4. Observe the error above. ### Expected behavior Copilot CLI should clear or ignore unsupported parameters when switching models, allowing /compact to run without errors. ### Additional context - The error does not occur if I switch back to a model supporting reasoning_effort. - This appears to be a session state compatibility issue when switching models.