_mcp-template-gated — MCP server template WITH the paywall gate baked in

This is the reusable factory template for every NEW MCP in the fleet. It is born with the server-side paywall gate already wired, so a new MCP can never again ship the premium tier for free (the bug that made conversion impossible on the first 10 servers).

The gate (the whole point)

• src/mcpServer.ts — the locally-installed package. The FREE tier (deep=false) runs here. The PREMIUM tier (deep=true) does NOT run here: it is forwarded to the hosted /pro/run endpoint with Authorization: Bearer <KEY>. No key → an upsell (the premium is never executed for free).

• src/server.ts — the hosted side. /pro/run is gated by two coexisting payment lanes:

  • x402 (USDC per call, for AI agents) via x402-express.

  • Stripe prepaid API key (for humans) — a valid Bearer key skips x402. The 402 body always shows BOTH lanes (pay_with_card_stripe + x402 accepts).

• src/stripeLane.ts — Stripe Checkout → webhook mints an API key into KV.

• src/kv.ts — Cloudflare KV (key store + funnel counters), degrades gracefully.

• src/engine.ts — EXAMPLE engine. Replace run(input,{deep}) with the real logic. Keep the contract: deep=false cheap/local, deep=true premium/server-only.

Related MCP server: Prepcast MCP

Make a new MCP from this template

1. Copy the folder: cp -r _mcp-template-gated <new-name>.

2. Replace placeholders across the repo:

   • ChainID Guard → human name, e.g. dns-doctor

   • chainid-guard → npm/url slug, e.g. dns-doctor

   • SERVICE_KEY → the buyer's env var, e.g. DNS_DOCTOR_KEY (PowerShell one-liner is in the comment block of scripts/rename.txt.)

3. In package.json/server.json/stripeLane.ts env defaults set:

   • STRIPE_KEY_PREFIX (e.g. dns_), STRIPE_PLAN_NAME, SERVICE_KEY_ENV, SERVICE_PRO_URL, homepage/PUBLIC_BASE_URL = the Vercel URL.

4. Write the real engine.ts and the real tool schema/description in mcpServer.ts.

5. npm install && npx tsc — must build clean.

Verify the gate (regla 7 — not done until this passes)

FORCE_LISTEN=true PORT=8899 PRO_API_KEYS=test_key X402_ENABLED=true node dist/server.js &
curl -s -o /dev/null -w "%{http_code}\n" "http://127.0.0.1:8899/run?target=x"                                  # 200 (free)
curl -s -o /dev/null -w "%{http_code}\n" "http://127.0.0.1:8899/pro/run?target=x"                              # 402 (no key)
curl -s -o /dev/null -w "%{http_code}\n" -H "Authorization: Bearer test_key" "http://127.0.0.1:8899/pro/run?target=x"  # 200 (paid key)
curl -s -o /dev/null -w "%{http_code}\n" -H "Authorization: Bearer wrong"    "http://127.0.0.1:8899/pro/run?target=x"  # 402 (bad key)

MCP stdio: deep=true without a key must print the UPSELL (never run premium); deep=false returns the local free result.

Production env (set in Vercel, sourced from config/)

STRIPE_SECRET_KEY, STRIPE_WEBHOOK_SECRET, CLOUDFLARE_ACCOUNT_ID/API_TOKEN/KV_NAMESPACE_ID, optionally SERVICE_KEY. Everything degrades gracefully if a lane is unconfigured — the x402 gate + 402 always work even with no Stripe/KV. Never set the deep engine to run client-side.