Apollo MCP Server Guide

Apollo MCP Server exposes GraphQL operations as MCP tools, enabling AI agents to interact with GraphQL APIs through the Model Context Protocol.

Quick Start

Step 1: Install

# Linux / MacOS
curl -sSL https://mcp.apollo.dev/download/nix/latest | sh

# Windows
iwr 'https://mcp.apollo.dev/download/win/latest' | iex

Step 2: Configure

Create config.yaml in your project root:

# config.yaml
transport:
  type: streamable_http
schema:
  source: local
  path: ./schema.graphql
operations:
  source: local
  paths:
    - ./operations/
introspection:
  introspect:
    enabled: true
  search:
    enabled: true
  validate:
    enabled: true
  execute:
    enabled: true

Start the server:

apollo-mcp-server ./config.yaml

The MCP endpoint is available at http://127.0.0.1:8000/mcp (streamable_http defaults: address 127.0.0.1, port 8000). The GraphQL endpoint defaults to http://localhost:4000/ — override with the endpoint key if your API runs elsewhere.

Step 3: Connect

Add to your MCP client configuration:

Streamable HTTP (recommended):

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "graphql-api": {
      "command": "npx",
      "args": ["mcp-remote", "http://127.0.0.1:8000/mcp"]
    }
  }
}

Claude Code:

claude mcp add graphql-api -- npx mcp-remote http://127.0.0.1:8000/mcp

Stdio (client launches the server directly):

Claude Desktop (claude_desktop_config.json) or Claude Code (.mcp.json):

{
  "mcpServers": {
    "graphql-api": {
      "command": "./apollo-mcp-server",
      "args": ["./config.yaml"]
    }
  }
}

Built-in Tools

Apollo MCP Server provides four introspection tools:

Tool	Purpose	When to Use
introspect	Explore schema types in detail	Need type definitions, fields, relationships
search	Find types in schema	Looking for specific types or fields
validate	Check operation validity	Before executing operations
execute	Run ad-hoc GraphQL operations	Testing or one-off queries

Defining Custom Tools

MCP tools are created from GraphQL operations. Three methods:

1. Operation Files (Recommended)

operations:
  source: local
  paths:
    - ./operations/

Each file must contain exactly one operation. Each named operation becomes an MCP tool.

# operations/GetUser.graphql
query GetUser($id: ID!) {
  user(id: $id) {
    id
    name
    email
  }
}

# operations/CreateUser.graphql
mutation CreateUser($input: CreateUserInput!) {
  createUser(input: $input) {
    id
    name
  }
}

2. Operation Collections

operations:
  source: collection
  id: your-collection-id

Use GraphOS Studio to manage operations collaboratively.

3. Persisted Queries

operations:
  source: manifest
  path: ./persisted-query-manifest.json

For production environments with pre-approved operations.

Reference Files

Detailed documentation for specific topics:

• Tools - Introspection tools and minify notation
• Configuration - All configuration options
• Troubleshooting - Common issues and solutions

Key Rules

Security

• Never expose sensitive operations without authentication
• Use headers configuration for API keys and tokens
• Disable introspection tools in production (they are disabled by default)
• Set overrides.mutation_mode: explicit to require confirmation for mutations

Authentication

# Static header
headers:
  Authorization: "Bearer ${env.API_TOKEN}"

# Dynamic header forwarding
forward_headers:
  - x-forwarded-token

# OAuth (streamable_http transport)
transport:
  type: streamable_http
  auth:
    servers:
      - https://auth.example.com/.well-known/openid-configuration
    audiences:
      - https://api.example.com

Token Optimization

Enable minification to reduce token usage:

introspection:
  introspect:
    minify: true
  search:
    minify: true

Minified output uses compact notation:

• T = type, I = input, E = enum
• s = String, i = Int, b = Boolean, f = Float, d = ID
• ! = required, [] = list

Mutations

Control mutation behavior via the overrides section:

overrides:
  mutation_mode: all       # Execute mutations directly
  # mutation_mode: explicit  # Require explicit confirmation
  # mutation_mode: none      # Block all mutations (default)

Common Patterns

GraphOS Cloud Schema

# schema.source defaults to uplink — can be omitted when graphos is configured
graphos:
  apollo_key: ${env.APOLLO_KEY}
  apollo_graph_ref: my-graph@production

Local Development

transport:
  type: streamable_http
schema:
  source: local
  path: ./schema.graphql
introspection:
  introspect:
    enabled: true
  search:
    enabled: true
  validate:
    enabled: true
  execute:
    enabled: true
overrides:
  mutation_mode: all

Production Setup

transport:
  type: streamable_http
endpoint: https://api.production.com/graphql
operations:
  source: manifest
  path: ./persisted-query-manifest.json
graphos:
  apollo_key: ${env.APOLLO_KEY}
  apollo_graph_ref: ${env.APOLLO_GRAPH_REF}
headers:
  Authorization: "Bearer ${env.API_TOKEN}"
health_check:
  enabled: true

Docker

transport:
  type: streamable_http
  address: 0.0.0.0
  port: 8000
endpoint: ${env.GRAPHQL_ENDPOINT}
graphos:
  apollo_key: ${env.APOLLO_KEY}
  apollo_graph_ref