[BUG] Accepting plan with 'clear context' discards file-read records — forces redundant re-reads during implementation

Preflight Checklist

• [x] I have searched existing issues and this has not 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?

When accepting a plan via ExitPlanMode and choosing "Yes, clear context", all file-read records from the planning phase are discarded. The Edit tool has a guardrail requiring that a file must be read before it can be edited, so Claude is forced to re-read every file it already read during planning before making any changes.

This creates a wasteful cycle:

1. Plan mode: Claude reads 10-20 files to understand the codebase and writes a detailed plan
2. Accept plan: User accepts and selects "clear context" to free up the context window
3. Implementation begins: Claude must re-read all the same files because the Edit tool no longer knows they were already read

The re-reads are pure overhead — Claude already understood the files well enough to write a plan referencing them, but the tooling forces it to read them again from scratch.

What Should Happen?

When context is cleared upon plan acceptance, the system should preserve a lightweight index of files that were read during planning (file path + last-read timestamp or content hash). This way the Edit tool's read-before-edit guardrail is satisfied without requiring full re-reads.

Alternatively, the plan file could include a manifest of files read during planning, and the system could treat those as "pre-read" when transitioning to implementation.

Steps to Reproduce

1. Enter plan mode on a non-trivial task requiring reading 5+ files
2. Let Claude explore the codebase and write a plan
3. Accept the plan and choose "Yes, clear context"
4. Observe that Claude re-reads every file it read during planning before it can make any edits

Impact

• Wastes tokens and wall-clock time on redundant file reads
• On larger tasks, re-reads can consume 30-50% of early implementation phase tokens
• Makes the "clear context" acceptance option feel like a penalty rather than a benefit — users want to reclaim context space but pay for it with redundant work

Related Issues

• #24686 — Plan itself lost after compaction (different: about plan content, not file-read records)
• #29890 — General context compaction losing working knowledge (broader scope)

Claude Model

Opus

Is this a regression?

No — this has been the behavior since plan mode was introduced

Claude Code Version

2.3.0 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Ghostty