graphql-to-mcp

Turn any GraphQL API into MCP tools — zero config, zero code.

Point graphql-to-mcp at a GraphQL endpoint and it auto-generates one MCP tool per query/mutation via introspection. Works with Claude Desktop, Cursor, Windsurf, and any MCP client.

Quick Start

{
  "mcpServers": {
    "my-api": {
      "command": "npx",
      "args": ["-y", "graphql-to-mcp", "https://countries.trevorblades.com/graphql"]
    }
  }
}

That's it. Claude can now query countries, continents, and languages.

Features

• Zero config — just provide a GraphQL endpoint URL

• Auto-introspection — discovers all queries and mutations automatically

• Flat parameter schemas — nested input objects are flattened for better LLM accuracy

• Smart truncation — large responses are intelligently pruned (array slicing + depth limiting)

• Auth support — Bearer tokens, API keys (header or query)

• Retry logic — automatic retries on 429/5xx with exponential backoff

• Include/exclude filters — expose only the operations you want

Usage

CLI

# Public API (no auth)
npx graphql-to-mcp https://countries.trevorblades.com/graphql

# With bearer token
npx graphql-to-mcp https://api.github.com/graphql --bearer ghp_xxxxx

# With API key
npx graphql-to-mcp https://api.example.com/graphql --api-key "X-API-Key:your-key:header"

# Filter operations
npx graphql-to-mcp https://api.example.com/graphql --include "get*" --exclude "internal*"

# With prefix (avoid name collisions when using multiple APIs)
npx graphql-to-mcp https://api.example.com/graphql --prefix myapi

Claude Desktop / Cursor Config

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": [
        "-y", "graphql-to-mcp",
        "https://api.github.com/graphql",
        "--bearer", "ghp_xxxxx",
        "--prefix", "github"
      ]
    }
  }
}

Programmatic

import { createServer } from "graphql-to-mcp";

const server = await createServer({
  endpoint: "https://api.example.com/graphql",
  auth: { type: "bearer", token: "xxx" },
  include: ["getUser", "listUsers"],
});

How It Works

1. Introspect — Fetches the GraphQL schema via introspection query

2. Flatten — Nested InputObject types are flattened into simple key-value parameters (e.g., input.name → input_name)

3. Generate — Each query/mutation becomes an MCP tool with a flat JSON Schema

4. Execute — When an LLM calls a tool, the flat args are reconstructed into proper GraphQL variables and sent to your endpoint

Why Flat Schemas?

LLMs are significantly better at filling flat key-value parameters than deeply nested JSON objects. By flattening InputObject types, we get:

• Higher accuracy in parameter filling

• Fewer hallucinated nested structures

• Better compatibility across different LLM providers

Options

Smart Truncation

GraphQL APIs can return large payloads that overwhelm LLM context windows. graphql-to-mcp automatically:

• Slices arrays to 20 items (with metadata showing total count)

• Prunes depth beyond 5 levels (with object/array summaries)

• Hard truncates at 50K characters as a safety net

Related

• mcp-openapi — Same zero-config approach for REST/OpenAPI APIs

License

MIT