The app only reads ONE specific keychain entry:
Service: "Claude Code-credentials"
This is the entry created by the official Claude Code CLI when you log in. The app:
1. Only reads - never writes, modifies, or deletes any keychain data
2. Only accesses this one service name - cannot read any other passwords, keys, or credentials
3. Extracts only the OAuth access token - used to call api.anthropic.com/api/oauth/usage
4. Sends data only to Anthropic's API - no analytics, no third-party servers
The token never leaves your machine except to Anthropic's own API endpoint. You can verify this yourself - the entire source is ~400 lines of Swift: https://github.com/richhickson/claudecodeusage
macOS will also prompt you the first time the app tries to access this keychain entry, giving you control to allow or deny.