[BUG] Project history collision between different Japanese-named directories with same path length

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?

ClaudeCodeCLIで 日本語のフォルダ名の中で作業すると、同じ文字数の他のプロジェクトと履歴が混ざって誤動作します

2.1.146 (Claude Code)

What Should Happen?

フォルダ名に日本語が使われていても適切に履歴管理をして欲しい

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Create two directories with different Japanese names of the same character length:

C:\work\案件あ\sample
C:\work\案件い\sample

1. Launch Claude Code CLI in the first directory and have a short conversation:

cd C:\work\案件あ\sample
claude
> This is a conversation in 案件あ

1. Exit Claude Code.
2. Launch Claude Code CLI in the second directory:

cd C:\work\案件い\sample
claude

1. Run /resume or otherwise inspect the conversation history.

Expected

• The second directory should have its own independent (empty or 案件い-specific) history.

Actual

• The conversation history from 案件あ appears under 案件い (and vice versa).
• Inspecting ~/.claude/projects/ shows that both paths map to the same project directory slug.

Additional context

• Non-ASCII (Japanese) characters in the path appear to be stripped or replaced with the same placeholder character when the project

slug is generated, so different paths of the same length collide.

• Tested on Windows 11 Pro 26100

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.146 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_