Model setting in settings.json is ignored on startup - defaults to Sonnet instead of configured Opus

[kazuph]

This issue was written with Claude Code (Claude Opus 4.5)

---

Description

When "model": "opus" is configured in ~/.claude/settings.json, Claude Code ignores this setting on startup and defaults to Sonnet instead.

Additionally, even when changing the model to Opus via /status → Config menu, this setting does not persist. On the next startup, it reverts to the default (currently Sonnet), making it impossible to maintain Opus usage across sessions.

Steps to Reproduce

1. Set "model": "opus" in ~/.claude/settings.json
2. Start Claude Code
3. Observe that the model is Sonnet, not Opus
4. Alternatively: Use /status → Config to set Opus
5. Restart Claude Code
6. Observe that the model has reverted to Sonnet

Expected Behavior

Claude Code should start with the model specified in settings.json (Opus in this case) and persist model selection across sessions.

Actual Behavior

Claude Code starts with Sonnet regardless of the settings.json configuration or previous session settings.

Configuration

{
  "$schema": "https://json.schemastore.org/claude-code-settings.json",
  "model": "opus",
  ...
}

Environment

• OS: macOS (Darwin 24.6.0)
• Claude Code: Latest version

Possibly Related Issues

• [Bug] Default model reverts to Haiku after removing config files #11291 - Default model reverts to Haiku after removing config files
• [BUG] Selecting model with /model deletes content of settings.json #3123 - /model command deletes settings.json content

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] /model setting does not persist across sessions despite “future sessions” claim #1523
2. [BUG] Claude Code not automatically loading .claude/settings.json during startup despite documentation indicating this should happen #7916
3. [BUG] .env value overriding model setting #12982

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[kazuph]

Update: I found that logging out and logging back in resolves this temporarily - after that, Claude Code correctly starts with Opus 4.5. This suggests there might be some cached state causing the issue rather than settings.json parsing itself.

[github-actions]

This issue has been inactive for 30 days. If the issue is still occurring, please comment to let us know. Otherwise, this issue will be automatically closed in 30 days for housekeeping purposes.