AI Usage Monitoring for Claude and Codex subscriptions

[tranquillum]

Hi 👋

I've been using cmux daily to drive multiple Claude and Codex agents and kept running into the same frustration: I'd hit a 5-hour or weekly subscription limit mid-task with no warning. Since cmux describes itself as a terminal "for managing multiple AI coding agents", it felt like the natural place to surface that information — right next to where the agents live.

Over the past week I built and have been daily-driving a sidebar-footer AI Usage Monitoring panel that:

• Shows per-account Session (5h) and Week usage bars with a time-pace marker so you can see whether you're burning quota faster than linear.
• Supports multiple accounts per provider (Personal / Work / etc.) — useful when you're juggling a personal subscription and a work one across tabs.
• Ships two providers today: Claude (claude.ai limits) and Codex (ChatGPT/Codex limits), plus status-page integration for both.
• Uses a generic UsageProvider / ProviderRegistry abstraction so adding a third provider is a matter of writing one fetcher + validator, no UI changes.
• Stores all credentials only in macOS Keychain, per-provider service name, never plaintext on disk, never logged, only ever sent to the provider's own API.

Screenshots and full write-up are in the PR: #2827

Thanks for reading, and thanks for cmux! 🙏