Claude Code Usage Monitor

A lightweight Windows taskbar widget that displays your Claude API rate limit usage in real time.

What it does

Embeds directly into the Windows taskbar and shows two progress bars:

• 5h — Session usage (5-hour rolling window)
• 7d — Weekly usage (7-day rolling window)

Each bar shows the current utilization percentage and a countdown until the rate limit resets.

How it works

1. Reads your Claude OAuth token from ~/.claude/.credentials.json, or from ~/.claude/.credentials.json inside an installed WSL distro if the Windows file is missing or expired (automatically refreshes expired tokens via the matching Claude CLI)
2. Queries the dedicated Anthropic OAuth usage endpoint (/api/oauth/usage) for utilization data
3. Falls back to the Messages API with rate limit header parsing (anthropic-ratelimit-unified-*) if the usage endpoint is unavailable
4. Renders the widget using Win32 GDI, embedded as a child window of the taskbar
5. Polls every 15 minutes by default (adjustable via context menu) and updates countdown timers between polls

The widget automatically detects dark/light mode from Windows system settings. You can drag the left divider to reposition the widget along the taskbar. Settings (position and poll frequency) are persisted to %APPDATA%\ClaudeCodeUsageMonitor\settings.json.

Requirements

• Windows 10/11
• Rust toolchain (MSVC target)
• An active Claude Pro/Team subscription with OAuth credentials stored by Claude Code

If you use Claude Code inside WSL2, keep claude installed and authenticated in that distro. The monitor will scan installed WSL distros and use the first accessible non-expired credential set it finds.

Building

cargo build --release

The binary will be at target/release/claude-code-usage-monitor.exe.

Usage

Run the executable — the widget appears in your taskbar.

• Drag the left divider to reposition the widget along the taskbar
• Right-click for a context menu with Refresh, Update Frequency, Settings (Start with Windows, Reset Position), and Exit

Project structure

src/
├── main.rs            # Entry point
├── models.rs          # UsageData / UsageSection types
├── poller.rs          # API polling, header parsing, formatting
├── window.rs          # Win32 window, rendering, message loop
├── native_interop.rs  # Win32 helper functions (taskbar, colors, etc.)
└── theme.rs           # Dark/light mode detection via registry

Releases

Pre-built Windows executables are available on the Releases page. Download claude-code-usage-monitor.exe and run it directly — no Rust toolchain required.

New releases are published automatically when a version tag is pushed:

git tag v1.0.0
git push origin v1.0.0