Claude per-model weekly usage is parsed generically from the OAuth payload's limits[] scoped entries (live probe disproved the seven_day_fable key guess). Grok now prefers ~/.grok/auth.json OIDC credentials against cli-chat-proxy.grok.com/v1/billing?format=credits for a real percent-used weekly credits window, falling back to the xAI API-key validity card. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>