Under the hood
A new internal classifier labels how each session is authenticated, for telemetry purposes
What
Claude Code now has a function that determines how the current session is logged in and sorts it into one of several categories: claude_ai_oauth, oauth_token_env, oauth_token_fd, auth_token_env, api_key_helper, wif, api_key, or none.
Why
This is internal bookkeeping that lets Anthropic break down telemetry and diagnostics by authentication method rather than treating all logins the same.