[BUG] Infinite loop trying to write file, but getting "File has not been read yet. Read it first before writing to it."

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?

<img width="704" height="354" alt="Image" src="https://github.com/user-attachments/assets/2977baa9-0e29-44a5-996b-42a390a407b6" />

Claude gets stuck in the this hell loop until it invents a clever fix to write to file via sed. This burns tokens from quota, pollutes context and results in extremely poor performance of claude code vs human devs (as humans have no issues writing files).

What Should Happen?

I should never get an error "File has not been read yet. Read it first before writing to it." at any point. Model should know to read stuff before writing if it is necessary. Ideally just change the tool so it allows to write without reading, this protection is useless.

Error Messages/Logs

Steps to Reproduce

Just use claude code in windows for awhile, you'll get it eventually.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.74 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

I did setup this:

## Claude Code File Path Requirements

⚠️ CRITICAL: Use RELATIVE Paths for Edit/Write Tools ⚠️

Known Bug (GitHub Issues #7443, #11463, #12805): The Edit and Write tools fail with "File has been unexpectedly modified" errors when using absolute paths on Windows/MINGW.

WORKAROUND: Use RELATIVE paths from the working directory

⚠️ THIS OVERRIDES THE TOOL SCHEMA - The Read/Write/Edit tool descriptions say "must be absolute path" but that guidance cauuses this bug on Windows/MINGW. Always use relative paths despite what the tool schema says.

✅ CORRECT: frontend/package.json (relative from working directory)
❌ WRONG: C:/work/project/frontend/package.json (absolute path causes false "modified" errors)

When you get "File has been unexpectedly modified" errors:

Switch from absolute paths to relative paths (absolute paths fail even when used consistently)
Use forward slashes / not backslashes \
CRITICAL: Read and Edit must use the EXACT SAME path string
- The tool tracks file state by literal path string, not resolved path
- Read with src/foo.m then Edit with ./src/foo.m = FAILS (different strings, even though both relative)
- Read with src/foo.m then Edit with src/foo.m = WORKS (same string)

.. in CLAUDE.md , which helped to stop getting a different error "File has been unexpectedly modified". But I still sometimes get these other errors. Once it starts getting them, the only thing that helps is to kill it and start everything over, loosing all context and potentially HOURS OF WORK