[MODEL] Claude ignores requests to change plan and keeps trying to escape plan mode

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude modified files I didn't ask it to modify

What You Asked Claude to Do

Update a plan

What Claude Actually Did

Present the same plan back to me and ask to exit plan mode

Expected Behavior

Claude is stuck in a loop and completely ignoring what you're asking for.
Here's what's happening:
The core problem: Claude is in some kind of "plan mode" and keeps re-presenting the exact same lengthy optimization plan every single time you respond — even when you explicitly tell it to scrap it. Three times in a row, it outputs the identical wall of text about N+1 joins, port mismatches, Redis caching, etc.
The specific failure: You asked for one simple thing — add timing/benchmarking instrumentation to measure where the slowness is. That's maybe 20-30 lines of performance.now() calls. Instead, Claude:

Ignores the actual request
Defaults to a pre-generated optimization plan it clearly already wrote
Keeps trying to "exit plan mode" (suggesting it's in some agentic tool-use flow where it needs approval to act)
Never actually implements anything

Why it keeps repeating: It appears to be in an agentic loop where it calls ExitPlanMode as a tool, that tool call isn't being approved or is failing silently, and then it just re-outputs the plan on the next turn as if nothing happened.
The irony: The plan itself is actually reasonable analysis — but it's completely useless when you explicitly said "scrap that plan, just add timing." Claude prioritized its own pre-generated output over your direct instruction, three times.
If you want, share the actual PostcodeMap.jsx and backend code here and I'll just add the benchmarking instrumentation directly — no plan, no optimization suggestions, just timing code.

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

_No response_

Claude Model

Sonnet

Relevant Conversation

Impact

Critical - Data loss or corrupted project

Claude Code Version

opus 4.5

Platform

Anthropic API

Additional Context

_No response_