Requests permission to enter plan mode. Use this tool only when the user
explicitly asks for planning or when there is exceptional architectural
ambiguity that requires user input before proceeding.

When to use:
1. User explicitly requests planning — "plan this out", "show me the approach first"
2. Exceptional architectural ambiguity — multiple approaches with fundamentally different trade-offs

When NOT to use — skip plan mode in almost all cases:
- The task is implementable even if it touches multiple files
- Standard patterns exist in the codebase
- Bug fixes and optimizations
- User wants to get started

Yolo mode users chose continuous execution. When in doubt, start coding rather than planning.
