feat: add @xmcp-dev/commet plugin for subscription-aware billing

[decker-dev]

Important: Please ensure your pull request is targeting the canary branch. PRs to other branches may be closed or require retargeting.

Summary

Adds @xmcp-dev/commet — a billing plugin that connects xmcp servers to Commet for subscription-aware feature gating and usage tracking.

Uses xmcp's idiomatic middleware/context pattern. The provider extracts the customer ID from a configurable request header and makes it available to standalone functions via context.

Setup

// src/middleware.ts
import { commetProvider } from "@xmcp-dev/commet";

export default commetProvider({
  apiKey: process.env.COMMET_API_KEY!,
  environment: "production",
});

Feature gating and usage tracking

import { check, track } from "@xmcp-dev/commet";

// Boolean gate — is this feature enabled on the customer's plan?
const result = await check("export");
if (!result.allowed) return result.message;

// Metered consumption — tracks 1 unit per call
const result = await track({ feature: "ai_generate", units: 1 });

// AI token tracking — automatic cost from model catalog
const result = await track({
  feature: "ai_chat",
  model: "anthropic/claude-haiku-4.5",
  inputTokens: 1200,
  outputTokens: 340,
});

Uses @commet/node SDK as a dependency — developers only need pnpm i @xmcp-dev/commet.

Type of Change

• Adding a feature
• Improving documentation
• Adding or updating examples

Affected Packages

• Documentation
• Examples

New package: packages/plugins/commet

Screenshots/Examples

The commet-http example includes 4 tools demonstrating each flow:

Tool	Method	Flow
search	none	Free tool, no gating
export	check()	Boolean gate, feature on/off per plan
ai_generate	track() with units	Metered consumption tracking
ai_chat	check() + track() with tokens	AI token tracking per model

Related Issues

N/A

[vercel]

@decker-dev is attempting to deploy a commit to the xmcp Team on Vercel.

A member of the Team first needs to authorize it.

[0xKoller]

Hoping to see also the quick demo vid if you can too! @decker-dev

[0xKoller]

Just a few tweaks!

[decker-dev]

Quick demo showing the 4 tools: free (no gating), boolean gate (export), metered usage (ai_generate), and AI token tracking (ai_chat).

demo_xmcp_commet.mp4

[0xKoller]

LGTM!