CodexIsland turns the MacBook notch into a Dynamic-Island-style live activity for Claude Code and Codex usage limits. The compact state is a black pill drawn with continuous (squircle) corners that match the hardware, sitting flush over the physical notch. Hover to peek at the 5-hour percentages; click to expand into a full Usage / Cost panel for both providers.
Two screens, swipeable. Usage shows Claude and Codex side by side across both 5-hour and 7-day windows, with five chart styles (Ring, Bar, Stepped, Numeric, Sparkline) you cycle by Cmd-clicking the panel. Cost reads your local Claude Code and Codex session logs — the same files `ccusage` reads, no extra auth — and estimates today and month-to-date dollar spend, billable-vs-all-token throughput, and a trend sparkline. Click-through is preserved outside the silhouette so the menu bar still works.
Pure Swift on AppKit + SwiftUI, with no Xcode project and no SwiftPM package. `build.sh` runs `swiftc` over `Sources/**/*.swift` and `lipo`-merges arm64 + x86_64 into a universal binary targeting macOS 13+. Local-first: the app never asks for credentials, instead reading tokens already created by the official tools (Codex's `~/.codex/auth.json`; Claude's `CLAUDE_CODE_OAUTH_TOKEN` env var → macOS Keychain → Anthropic OAuth refresh fallback) and calling only the providers' own usage endpoints. No telemetry, no analytics, no proxy.
Distributed unsigned through a Homebrew tap (`brew install --cask ericjypark/tap/codexisland`) and direct DMG. Auto-updates ship through Sparkle with EdDSA-signed appcasts published from a GitHub Actions release pipeline — verifiable cryptographically without involving Apple's $99/year Developer ID infrastructure. MIT-licensed, open source, and free.