Claude Code autonomously switches model mid-session despite --model flag

[renatogcarvalho]

Description

Claude Code is autonomously switching the model during a session, even though a specific model was set via the --model CLI flag at launch. The model change is not initiated by the user — Claude itself is switching it mid-session.

Steps to Reproduce

1. Launch Claude Code with an explicit model flag:

   claude --model claude-opus-4-6

2. Use Claude Code normally during the session
3. Observe that the model indicator changes (e.g., from Opus 4.6 to Sonnet 4.6) without user action

Expected Behavior

The model set via --model should remain active for the entire session unless the user explicitly switches it (e.g., via /model).

Actual Behavior

Claude Code autonomously switches to a different model mid-session without user input.

Environment

• Platform: macOS (Darwin 25.2.0)
• Model: claude-opus-4-6

Workaround

Setting availableModels in .claude/settings.json to restrict to a single model may prevent this, but it also prevents legitimate user model selection via CLI flags.

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] switch model itself #24155
2. [Bug] Unexpected Model Switching Between Terminal Sessions #7341
3. [Bug] Claude ignores --model flag in prompt mode, uses Sonnet instead of selected model #22362

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🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate of #24155.

If this is incorrect, please re-open this issue or create a new one.

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.