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:

Defining Custom Tools

MCP tools are created from GraphQL operations. Three methods:

1. Operation Files (Recommended)

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

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

mutation CreateUser($input: CreateUserInput!) {
  createUser(input: $input) {
    id
    name
  }
}

Each named operation becomes an MCP tool.

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: ${env.APOLLO_GRAPH_REF}
health_check:
  enabled: true

Ground Rules

• ALWAYS configure authentication before exposing to AI agents
• ALWAYS use mutation_mode: explicit or mutation_mode: none in shared environments
• NEVER expose introspection tools with write access to production data
• PREFER operation files over ad-hoc execute for predictable behavior
• PREFER streamable_http transport for remote and multi-client deployments
• USE stdio only when the MCP client launches the server process directly
• USE GraphOS Studio collections for team collaboration