claude-usage-mcp

A tiny MCP server that reports your Claude subscription usage — the 5-hour and weekly limit windows — with a forecast and a velocity recommendation. No API key required: it reuses the OAuth session that Claude Code already stores on your machine, exactly like Claude Code's own /usage command.

How it works

1. Reads Claude Code's OAuth credentials from ~/.claude/.credentials.json (or the macOS Keychain item Claude Code-credentials), refreshing the access token when needed.
2. Calls the undocumented usage endpoint GET https://api.anthropic.com/api/oauth/usage with Authorization: Bearer <token> and anthropic-beta: oauth-2025-04-20. The response contains five_hour, seven_day and seven_day_opus, each with utilization (0–100) and resets_at.
3. Because Anthropic's edge fingerprints the TLS handshake and rejects Node's fetch with 403 "Request not allowed", the server tries fetch first and falls back to the system curl binary (which is accepted). curl ships with Windows 10+, macOS and Linux. Set CLAUDE_USAGE_FORCE_CURL=1 to skip straight to curl.

You must be signed in via Claude Code (claude) for this to work.

Tools

get_usage

No arguments. Returns every available window with: utilization, resetsAt, remainingHours, projectedEndUtilization (where you'd land at reset at the current pace), exhaustAt (when you'd hit 100% if you will), and velocityRecommendation.

get_velocity

Argument window: "5h", "weekly", or "weekly_opus". Returns just the velocity recommendation and forecast for that one window.

The velocity recommendation (0–120%)

A single number telling you how hard you can push. It compares the sustainable pace (the rate that exactly finishes the quota at reset) to your current average pace:

• 100% — full speed. At your current pace you land exactly at the limit right when the window resets.
• < 100% — the fraction of your current pace you should slow to in order not to run out early. e.g. 40% = go at roughly 40% of your current speed.
• > 100% (capped at 120%) — you have so much headroom you can't burn through the quota at anything like this pace. Go all out.

The 5-hour and weekly windows are evaluated separately, so you get 5h and weekly velocities independently.

Math per window (length L = 5h or 168h, utilization u%, reset at R):

elapsed   = now - (R - L)
remaining = R - now
rate      = u / elapsed                       # % per hour
forecast  = u / (elapsed / L)                 # % at reset if pace continues
exhaustAt = now + (100 - u) / rate            # only if forecast > 100
velocity  = ((100 - u) / remaining) / rate * 100   # clamped to [0, 120]

Install & build

npm install
npm run build

Register with an MCP client

Claude Desktop (claude_desktop_config.json), or any stdio MCP client:

{
  "mcpServers": {
    "claude-usage": {
      "command": "node",
      "args": ["/absolute/path/to/claude-usage-mcp/dist/index.js"]
    }
  }
}

Caveats

• The usage endpoint is undocumented and can change or disappear without notice — treat it as best-effort.
• The server can read your Claude Code OAuth tokens (the same file Claude Code itself uses). It never sends them anywhere except Anthropic's own endpoints, and passes the bearer token to curl via a stdin config file so it never appears in the process list.
• Velocity uses the average pace over the elapsed window (one snapshot per call). It's a guide, not a guarantee; a burst right before reset can still overshoot.

License

MIT