[BUG] missing documentation

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The parameter "defaultMode": "plan" configured in _~/.claude/settings.json_ has no effect. Claude Code always starts in normal mode instead of plan mode despite this configuration.

What Should Happen?

When "defaultMode": "plan" is configured in _~/.claude/settings.json_, Claude Code should automatically start in plan mode instead of normal mode.
Alternatively, if this setting is not supported, an error or warning should be displayed to inform the user that the configuration is invalid.

Error Messages/Logs

No error message displayed. The configuration is silently ignored.

Steps to Reproduce

1. Create or edit the file ~/.claude/settings.json
2. Add the parameter: "defaultMode": "plan"
3. Start Claude Code in a project
4. Note that Claude starts in normal mode, not in plan mode

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.55

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

Complete configuration tested in ~/.claude/settings.json:
_{
"defaultMode": "plan",
"sandbox": {
"enabled": true
},
"permissions": { ... }
}_
Documentation search:

• No documentation found on docs.claude.com regarding "defaultMode"
• No mention in the GitHub README for anthropics/claude-code
• No reference in the documentation on platform.claude.com

Note: If this parameter is not/no longer supported, it would be useful to document this or return a warning when it is used.