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
2. Sends a minimal API request to the Anthropic Messages API
3. Parses rate limit headers (anthropic-ratelimit-unified-*) from the response
4. Renders the widget using Win32 GDI, embedded as a child window of the taskbar
5. Polls every 15 minutes (adjustable) and updates countdown timers between polls

The widget automatically detects dark/light mode from Windows system settings.

Requirements

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

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. Right-click for a context menu with Refresh, Update Frequency and Exit options.

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 v0.1.0
git push origin v0.1.0