[BUG] Claude Code automatically reverts user code changes without permission

(claude --version)
⎿  1.0.60 (Claude Code)

Environment

• Platform (select one):
• Anthropic API
• AWS Bedrock
• Google Vertex AI
• Other:
• Claude CLI version: 1.0.60 (Claude Code)
• Operating System: Linux 6.14.2-300.fc42.x86_64 (Fedora)
• Terminal: bash

Bug Description

Claude Code automatically reverts legitimate user code changes without
permission or configuration. When editing TypeScript/React files,
intentional code modifications get automatically changed back to a
"preferred" format, preventing legitimate development work.

Steps to Reproduce

1. Open a Next.js TypeScript project in Claude Code
2. Edit a file to change className="h-screen pt-20" to

className="h-[calc(100vh-80px)]"

1. Save the file or wait briefly
2. Observe that the file content automatically reverts to the original

h-screen pt-20

1. System reminders appear stating "file was modified, either by the user or

by a linter"

Expected Behavior

User code changes should persist unless explicitly formatted through
user-initiated commands. Development tools should not automatically modify
code without explicit user permission or configuration.

Actual Behavior

Files are automatically modified back to a "preferred" format, overriding
intentional user changes. This happens even when:

• No Prettier configuration exists
• ESLint is disabled (eslint.config.mjs renamed to .disabled)
• Next.js ESLint integration is disabled
• No VS Code format-on-save settings found
• No git hooks or pre-commit tools detected

Additional Context

• This blocks legitimate CSS class modifications needed for layout fixes
• Behavior persists across multiple file edits and tool restarts
• No user configuration found that controls this auto-formatting
• Violates fundamental principle that IDEs should not modify code without

consent

• Impact: Unable to use Claude Code due to automatic code

reversion