prestige-entitlement

Standalone RevenueCat MCP entitlement proxy for Burning Token 2026.

This is not part of prestige-mcp. It sits in front of PrestigeMCP as a separate package: schema compression and tiered loading stay in prestige-mcp; this repo only does boolean entitlement gating.

What it does

1. Maps an authenticated PrestigeMCP principal to a trusted RevenueCat customer id (server-side, never client-supplied at call time).

2. tools/list previews locked premium tools after PrestigeMCP compression/tiering.

3. tools/call answers ENTITLEMENT_REQUIRED locally. Blocked premium calls never reach the upstream MCP server.

4. Signed RevenueCat webhooks update a local cache. Execution does not call RevenueCat.

5. Fail closed for premium if the cache is unverifiable. Free tools stay up during an outage.

6. Emits notifications/tools/list_changed when entitlements change the catalog.

7. GoldTrac-compatible evidence receipts. No payment details, secrets, or raw principals.

Related MCP server: Enterprise MCP Gateway and Tool Registry

Demo (seven beats)

npm install
npm test
npm run demo

1. Free tool succeeds.

2. Premium tool is blocked.

3. RevenueCat entitlement is activated.

4. Signed webhook updates the proxy.

5. Tool catalog refreshes.

6. Premium tool succeeds.

7. Evidence records authorization and execution.

HMAC

X-RevenueCat-Webhook-Signature: t=<unix>,v1=<hmac_sha256_hex> over "<t>." + rawBody. Verify the untouched raw bytes, constant-time compare, 300s timestamp window, event.id idempotency.

Set REVENUECAT_WEBHOOK_SECRET in the environment. Sandbox fixtures use whsec_sandbox_not_a_real_secret. Never commit live keys.

Error shape

JSON-RPC success with MCP tool result isError: true and structuredContent.code = "ENTITLEMENT_REQUIRED" plus upgradeUrl. This is not JSON-RPC -32002.

Run as a proxy

REVENUECAT_WEBHOOK_SECRET=... npx tsx src/cli.ts --webhook-port 8787 -- npx tsx src/cli.ts --sample

Or --sample for an in-process premium catalog (echo, add, goldtrac_trace, premium_forecast).