Agent Island

Agent Island is a free, MIT-licensed desktop app that lives in the macOS menu bar or Windows system tray and monitors your AI coding agents in real time. Built by independent developer Tristan Tang, it supports Claude Code, Codex, Antigravity, Grok, and Cursor — all computed locally with no account required and no product telemetry. The homepage states it is trusted by 3,000+ users and has been listed in numerous curated directories including awesome-mac, awesome-swift-macos-apps, and Product Hunt.

What It Is

Agent Island is a native status companion that reads the session files your AI coding agents already write to disk and calls each provider's official usage API using credentials already stored on your machine. It surfaces live session state (working, waiting, stalled, or your turn), quota windows with reset countdowns, and estimated API value — all without wrapping or intercepting agent traffic. On macOS it is a SwiftUI universal binary (Apple Silicon and Intel); on Windows it is a native WPF app. Neither platform uses Electron.

How It Works

• Local-first processing: Session indexes, preferences, and caches live in standard local app storage. No data leaves the machine; the only outbound calls are to each provider's own usage endpoints using your existing credentials.
• Turn detection: The app reads explicit end-of-turn markers — Claude's stop reason, Codex's task-complete event, Grok's turn-completed event — rather than polling or intercepting traffic.
• Two-slot island: Pick any two of the five supported agents for the compact menu-bar display; all agents retain full data rows in the expanded panel.
• Alerts: Your-turn notifications queue rather than replace each other. While the agent's app is frontmost, the alarm holds and fires when you switch away. An optional chime can sound even while frontmost. Subagent child threads are filtered out and never trigger alerts.
• Quota management: Shows used percentage and reset countdown for each provider's rolling window (e.g., 5-hour and weekly windows). Polling interval is configurable at 5, 15, or 30 minutes.

Supported Agents and Platform Coverage

Five agents are supported as of v2.1.2: Claude Code, Codex, Antigravity (formerly Gemini Code Assist for individuals, after Google retired that product on 2026-06-18), Grok, and Cursor. Live session state covers Claude Code, Codex, Grok, and Antigravity; Cursor contributes billing-cycle usage, plan tier, and your-turn alarms via its own completion signal. The capabilities matrix on the site notes that macOS is the primary verified platform, with Windows UI paths independently verified using injected demo data on a CI runner.

Setup Path

On macOS, installation is a single Homebrew command (brew install tristan666666/tap/agentisland) or a DMG download. On Windows, users download a win-x64 ZIP from the GitHub releases page and run AgentIsland.exe, or install via WinGet or Scoop. The app requires no Agent Island account. macOS requires one right-click → Open on first launch because the build is ad-hoc signed without a paid Apple Developer certificate; updates are verified via Sparkle with EdDSA signatures.

Update: v2.1.2 (fiveblade)

The current release is v2.1.2, tagged "fiveblade" (audited 2026-08-09). Key changes in this release include Cursor gaining full live session state and your-turn alarms (previously only billing-cycle data), Windows shipping the same five providers and live session state as macOS from the same release tag, and the Gemini slot migrating automatically to Antigravity following Google's retirement of individual Gemini Code Assist accounts. The Homebrew cask is at v2.1.2; WinGet and Scoop manifests were still at v1.7.1 as of the audit date, with the direct ZIP at v2.1.2.