Claude Usage Monitor - Taskbar Widget + Popup Window

A Windows tray app that shows your Claude.ai usage at a glance - including a widget embedded directly in the taskbar.

How it works

The app reads the OAuth token that Claude Code stores in your Windows Credential Manager, then calls the Anthropic OAuth usage API. One HTTP request. No browser, no cookies, no WebView2, no manual configuration.

Requirements:

You need Claude Code installed and logged in (claude login) and .NET 8 - zero external dependencies.

Setup

Use the ClaudeUsageMonitor.exe from the latest release

Or build it yourself:

git clone https://github.com/Firnschnee/Tray-Usage-Monitor.git
cd Tray-Usage-Monitor
dotnet build -c Release
dotnet run

That's it. If you're logged into Claude Code, the tray icon should show your session usage within seconds.

What you see

• Taskbar widget — embedded next to the system tray, always visible. Shows two progress bars (5h session + 7d weekly) with percentage and countdown, green/yellow/red by utilization. Updates automatically when the displayed countdown changes.
• Tray icon with session percentage (green/yellow/red)
• Tooltip with session %, weekly % (with pace), and reset timers
• Right-click menu: Details, Refresh, Copy Raw JSON, Exit
• Popup window — opens on startup and on double-click, always on top. Three progress bars: 5h session, 7d weekly, extra usage monthly — with colored pace markers and subtitles (e.g. Reset: 1h 23m | +12% ahead)

If taskbar embedding isn't available (unsupported shell, modified taskbar), the app falls back gracefully to tray icon + popup only.

How it actually works (technically)

1. Reads "Claude Code-credentials" from Windows Credential Manager, then falls back to %USERPROFILE%\.claude\.credentials.json (and %HOMEDRIVE%%HOMEPATH%\.claude\ as a second fallback)
2. Extracts the claudeAiOauth.accessToken
3. Calls GET https://api.anthropic.com/api/oauth/usage with Bearer auth
4. Parses five_hour, seven_day, and extra_usage from JSON response
5. Updates tray icon every 2 minutes (every 60 seconds while the widget is open)

Inspired by omachala's bash gist which does the same thing for macOS/CLI.

Token expired?

Run claude login in your terminal. The app picks up the new token automatically on the next poll cycle.

Project structure

├── Program.cs            # Entry point
├── MainForm.cs           # Tray icon, polling, UI orchestration
├── TaskbarWidget.cs      # Taskbar-embedded widget (Win32 reparenting + layered window)
├── Win32Interop.cs       # P/Invoke declarations for Win32 APIs
├── UsageFetcher.cs       # Single HTTP call to Anthropic API
├── UsageData.cs          # Data model
└── CredentialReader.cs   # Reads OAuth token from Credential Manager / file

License

MIT License – See LICENSE file