[BUG] Claude Code does not respect file encoding, corrupts Windows-1252 files

[edlyra]

Environment

• Platform (select one):
  • [ X] Anthropic API
  • AWS Bedrock
  • Google Vertex AI
  • Other:
• Claude CLI version: 1.0.103 (Claude Code)
• Operating System: Windows 11
• Terminal: VSCode

Bug Description

Claude Code does not respect the original file encoding when editing files. It assumes UTF-8 encoding for all operations, which causes character corruption when working with files encoded in other formats like Windows-1252.

Steps to Reproduce

1. Open a file that is encoded in Windows-1252 (common for Delphi/Pascal projects)
2. Use Claude Code's Edit tool to modify text containing accented characters (e.g., Portuguese: configuração, não)
3. The file becomes corrupted with characters like configuração instead of configuração

Expected Behavior

Claude Code should:

• Detect the original file encoding
• Preserve the same encoding when making edits
• Or provide a way to configure the target encoding for edits

Current Workaround

Users must either:

1. Accept corrupted characters and manually fix them
2. Maintain separate UTF-8 clones of their repositories specifically for Claude Code usage
3. Use pre-commit scripts to convert between encodings

Impact

This affects any codebase that uses non-UTF-8 encoding, particularly:

• Legacy Delphi/Pascal projects (Windows-1252)
• Projects with specific encoding requirements
• International projects with accented characters

Technical Details

• Claude Code's Read tool correctly displays Windows-1252 files
• The Edit/Write tools force UTF-8 output regardless of input encoding
• VSCode correctly shows Windows-1252 files when configured properly
• The issue only occurs when Claude Code modifies the files

Environment

• Claude Code version: [current version]
• File encoding: Windows-1252 (ANSI - Latin 1)
• IDE: Delphi XE
• Language: Portuguese (Brazilian) with accented characters

This is a critical issue for maintaining legacy codebases that require specific encodings for compiler compatibility.

[github-actions]

Found 3 possible duplicate issues:

1. Character Encoding Handling Fails for WINDOWS-1252 ADVPL Files #3416
2. [BUG] Edit tool corrupts Windows-1252 encoding to UTF-8 #5518
3. File Encoding Limitation: Edit Tool Overwrites Non-UTF-8 Files #6485

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🤖 Generated with Claude Code

[corneliusroemer]

Please give your issue a descriptive title

[edlyra]

fixing the errors generated by this issue consumes a lot of tokens

[ohuet]

2 workarounds are on this older ticket : #3416

The best is probably to use this : https://github.com/devslimbr/cc-tools

[github-actions]

This issue has been inactive for 30 days. If the issue is still occurring, please comment to let us know. Otherwise, this issue will be automatically closed in 30 days for housekeeping purposes.