BUG] Plan mode assumes implementation after approval, even when user only asked to document the plan

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?

Description

When in plan mode, if the user asks Claude to "just document the plan" (e.g., write it to a markdown file), Claude calls ExitPlanMode to get approval. After the user approves, Claude ignores the original "document only" instruction and starts implementing the plan (creating code, models, migrations, etc.).

Claude treats ExitPlanMode approval as a green light to implement the full plan, ignoring the "document only" request.

What Should Happen?

After approval, Claude should only create the documentation file with the plan contents and stop — respecting the user's explicit "document only" instruction.

Error Messages/Logs

Steps to Reproduce

1. Enter plan mode for a complex task (e.g., a data migration)
2. Iterate on the plan until satisfied
3. Ask Claude: "just document this, don't implement" (or similar)
4. Claude calls ExitPlanMode
5. User approves
6. Claude starts writing implementation code instead of just saving the plan as documentation

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.37 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Cursor

Additional Information

_No response_