Lib

npm version npm downloads TypeScript license

Convert GraphQL schemas and endpoints into Model Context Protocol (MCP) servers. Point at any GraphQL API and get an MCP server with tools mapped from queries and mutations.

Features

• Zero config proxy — pass a GraphQL endpoint URL and get an MCP server with every query as a tool
• Library mode — add GraphQL-backed tools to your existing TypeScript MCP server with one function call
• Mutation control — expose all mutations, none, or an explicit whitelist
• MCP tool annotations — queries get readOnlyHint: true, mutations get destructiveHint: true
• Multiple schema sources — SDL files, globs, introspection JSON, inline SDL strings, or live URL introspection
• Multi-endpoint — combine multiple GraphQL APIs into a single MCP server with prefix-based namespacing
• Include/exclude filters — cherry-pick which operations become tools
• ESM only — modern, tree-shakeable, with complete TypeScript types

Quick Start

Proxy Mode

Run against a live GraphQL endpoint (introspects the schema automatically):

npx graphql2mcp https://api.example.com/graphql -t http

This starts a Streamable HTTP MCP server on port 3000. For stdio transport (used by Claude Desktop, Cursor), omit the -t http flag:

npx graphql2mcp https://api.example.com/graphql

Or from a local SDL file:

npx graphql2mcp schema.graphql -e https://api.example.com/graphql -t http

Library Mode

Add GraphQL tools to an existing MCP server:

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
import { registerGraphQLTools } from '@graphql2mcp/lib';

const server = new McpServer({ name: 'my-server', version: '1.0.0' });

// Register your own tools alongside GraphQL tools
registerGraphQLTools(server, {
    source: 'schema.graphql',
    endpoint: 'https://api.example.com/graphql'
});

const transport = new StreamableHTTPServerTransport({ sessionIdGenerator: undefined });
await server.connect(transport);

Or use getGraphQLTools for full control over registration:

import { getGraphQLTools } from '@graphql2mcp/lib';

const { tools } = getGraphQLTools({
    source: 'schema.graphql',
    endpoint: 'https://api.example.com/graphql'
});

for (const tool of tools) {
    server.registerTool(
        tool.name,
        {
            title: tool.title,
            description: tool.description,
            inputSchema: tool.inputSchema,
            annotations: tool.annotations
        },
        tool.handler
    );
}

Packages

This is a monorepo managed with pnpm workspaces:

Package	Description
graphql2mcp	Standalone CLI proxy — point at a GraphQL endpoint, get an MCP server
@graphql2mcp/core	Shared engine — schema loading, tool generation, execution, and MCP server registration
@graphql2mcp/lib	Library for integrating into existing TypeScript MCP servers

How It Works

flowchart TD
    subgraph Input
        A[SDL File] --> L
        B[Inline SDL] --> L
        C[Introspection JSON] --> L
        D[Glob Pattern] --> L
        E[Live URL] --> U
    end

    L[loadSchema] --> S[GraphQLSchema]
    U[loadSchemaFromUrl] --> S

    subgraph "@graphql2mcp/core"
        S --> G[generateTools]
        G --> T[ToolDefinition]
    end

    subgraph MCP Server
        T --> R[registerTool]
        R --> Q[Tool Called]
    end

    Q -->|POST query + variables| EP[GraphQL Endpoint]
    EP -->|JSON response| Q

1. Load — read a GraphQL schema from an SDL file (or glob of multiple files), introspection JSON, inline SDL string, or live URL introspection
2. Parse — build a GraphQLSchema object using the graphql library
3. Generate — walk every Query and Mutation field, mapping arguments to Zod schemas, building field selections, and producing ToolDefinition objects with names, descriptions, annotations, and pre-built query documents
4. Register — add each tool to an McpServer. When an AI agent calls a tool, the server executes the corresponding GraphQL operation against the endpoint and returns the result as JSON

Runtime Compatibility

Runtime	Version	Status
Node.js	>= 22	Tested
Bun	>= 1.2	Tested
Deno	>= 2.0	Tested

Development

pnpm install
pnpm build
pnpm test

License

MIT