MCP Relay Server

A lightweight MCP server that exposes provider-specific tools and relays HTTP requests to configured providers (Supabase, Vercel, Context7, etc.).

Quick start

Install dependencies

npm install

Set up environment variables

Set environment variables for provider auth tokens (locally or in your host settings):

CONTEXT7_API_KEY=your-token-here
SUPABASE_URL=https://your-project.supabase.co
SUPABASE_ANON_KEY=your-key-here

Example for your shell:

PowerShell: $env:CONTEXT7_API_KEY = "your-token"
Bash: export CONTEXT7_API_KEY="your-token"

Add a provider

npm run build
node dist/cli.js add

Run the relay (stdio transport)

node dist/index.js

Run the relay (HTTP transport)

node dist/httpServer.js

Provider config

Provider configs live in providers/*.json.

Example:

{
  "name": "supabase",
  "type": "http",
  "baseUrl": "https://YOUR_PROJECT.supabase.co",
  "description": "Supabase REST API",
  "auth": {
    "type": "bearer",
    "env": "SUPABASE_TOKEN"
  },
  "defaultHeaders": {
    "apikey": "${SUPABASE_ANON_KEY}"
  },
  "allowMethods": ["GET", "POST"],
  "allowPaths": ["/rest/v1/"]
}

Note: set any secrets via environment variables (locally or in your host). ${ENV_VAR} placeholders in baseUrl and defaultHeaders are expanded at runtime.

Presets: providers/vercel.json uses VERCEL_TOKEN. providers/supabase.json uses SUPABASE_URL and SUPABASE_ANON_KEY.

Tools

Each provider creates a tool named:

provider.<name>.request

Inputs:

path: path starting with /
method: HTTP method
headers: additional headers
query: query params
body: string or JSON

Optional provider fields:

allowMethods: restricts allowed HTTP methods.
allowPaths: list of allowed path prefixes.

The server also exposes:

relay.list_providers

CLI flags

node dist/cli.js add --name supabase --base-url https://xyz.supabase.co --auth bearer --auth-env SUPABASE_TOKEN

One-click deploy

Replace YOUR_REPO_URL with your GitHub repo URL.

Vercel (serverless, stateless MCP HTTP at /mcp):

Render (long-running HTTP server on /mcp):

Set env vars in your hosting dashboard for any providers you configure (for example VERCEL_TOKEN, CONTEXT7_API_KEY, SUPABASE_URL, SUPABASE_ANON_KEY).

HTTP settings

PORT: port for the HTTP server (default: 3000).
HOST: bind address for the HTTP server (default: 0.0.0.0).
MCP_PATH: HTTP path for MCP (default: /mcp).

Build

npm run build

mcprelay