rest-mcp-wrapper

Wrap any REST API as an MCP server with a single config object. Each endpoint becomes a tool the LLM can call — no boilerplate, no manual tool registration.

Install

npm install rest-mcp-wrapper

Quick start

import { createRestMcpServer } from "rest-mcp-wrapper";

createRestMcpServer({
  server: { name: "my-api", version: "1.0.0" },
  api: {
    baseUrl: "https://api.example.com",
    auth: { type: "bearer", token: process.env.API_TOKEN ?? "" },
  },
  endpoints: [
    {
      name: "get_user",
      description: "Get a user by their ID",
      method: "GET",
      path: "/users/{id}",
      params: {
        id: { in: "path", type: "string", description: "User ID" },
      },
    },
    {
      name: "create_post",
      description: "Create a new post",
      method: "POST",
      path: "/posts",
      params: {
        title:   { in: "body", type: "string", description: "Post title" },
        content: { in: "body", type: "string", required: false, description: "Post body" },
      },
    },
  ],
});

Build and run:

npx tsc
node --env-file=.env build/server.js

Configuration

server

api

endpoints[]

Parameters

Each key in params is a flat parameter the LLM will provide. The in field controls where it goes in the request.

params: {
  id:       { in: "path",   type: "string",  description: "User ID" },
  search:   { in: "query",  type: "string",  required: false },
  title:    { in: "body",   type: "string" },
  x_org_id: { in: "header", type: "string",  description: "Organisation ID" },
}

ParamDef

Body params on GET and DELETE requests are automatically promoted to query params.

Authentication

Pass one of the following as api.auth. Credentials should always come from environment variables.

// Bearer token
auth: { type: "bearer", token: process.env.TOKEN ?? "" }

// API key in a header
auth: { type: "apikey", key: process.env.API_KEY ?? "", headerName: "X-Api-Key" }

// API key as a query parameter
auth: { type: "apikey", key: process.env.API_KEY ?? "", queryParam: "api_key" }

// HTTP Basic auth
auth: { type: "basic", username: process.env.USER ?? "", password: process.env.PASS ?? "" }

// Custom headers
auth: { type: "custom", headers: { "X-Tenant": process.env.TENANT ?? "" } }

// No auth
auth: { type: "none" }

OpenAPI / Swagger import

If your API publishes an OpenAPI 3.x spec, you can generate all endpoints automatically instead of defining them by hand.

curl https://api.example.com/openapi.json -o openapi.json

import { createRestMcpServer, fromOpenApi } from "rest-mcp-wrapper";
import spec from "./openapi.json" with { type: "json" };

createRestMcpServer({
  server: { name: "my-api", version: "1.0.0" },
  api: { baseUrl: "https://api.example.com", auth: { type: "bearer", token: process.env.TOKEN ?? "" } },
  endpoints: fromOpenApi(spec),
});

You can also mix: use fromOpenApi as a base and spread in manual overrides or additions.

endpoints: [
  ...fromOpenApi(spec),
  { name: "custom_tool", description: "...", method: "POST", path: "/custom" },
]

Claude skill

A Claude Code slash command is included to generate a server file from a plain-English description of an API.

Copy .claude/commands/create-mcp-server.md to:

• ~/.claude/commands/ for global use across all projects
• .claude/commands/ inside a specific project

Then run:

/create-mcp-server The Stripe API for payments — docs at stripe.com/docs/api

Claude will fetch the docs, infer the endpoints, and write a ready-to-run server.ts for you.

TypeScript

All config types are exported for use in typed projects:

import type { RestMcpConfig, EndpointDef, ParamDef, AuthStrategy } from "rest-mcp-wrapper";

const endpoints: EndpointDef[] = [ ... ];

const config: RestMcpConfig = {
  server: { name: "my-api", version: "1.0.0" },
  api: { baseUrl: "https://api.example.com" },
  endpoints,
};

License

MIT