[BUG] 2.1.77 (Claude Code) - ExitPlanMode presents stale plan file content when re-entering plan mode

[unmateria]

Preflight Checklist

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

What's Wrong?

When re-entering plan mode in a conversation where a previous plan file already exists, ExitPlanMode displays the contents of the old plan file to the user — even if the current planning session has nothing to do with the previous one.

What Should Happen?

ExitPlanMode should either:

• Require the plan file to have been written/edited during the current plan mode session before allowing exit, OR
• Warn Claude (or the user) that the plan file content appears unchanged from a previous session, OR
• Clear the plan file when re-entering plan mode for a different task

Error Messages/Logs

Steps to Reproduce

1. Start a conversation and enter plan mode for Task A
2. Write a detailed plan to the plan file, exit plan mode, and implement it
3. Later in the same conversation, enter plan mode again for Task B (completely unrelated)
4. The system prompt correctly warns: "A plan file exists... evaluate the user's current request against that plan"
5. If Claude calls ExitPlanMode without fully overwriting the plan file, the user is presented with the old Task A plan as if it were the proposal for Task B

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.1.77 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

I think is just when... after finishing a 'big' plan and implementing it (but not much tokens in context, just 87k), I ask him to do a very very little thing without plan mode, and I ask him to do another little big plan in plan mode again. Happened several times in several sessions, and I think it was the same in all.

[github-actions]

Found 3 possible duplicate issues:

1. [Bug] Stale plan file from previous session loaded instead of creating new plan #30398
2. [Bug] Plan mode resurfaces old plans after session compaction with Claude 4.5 Opus #12505
3. Plan mode shows previous plan instead of new one when switching modes mid-input #37644

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

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🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate of #30398.

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.