mcp-graphql-enhanced

An enhanced MCP (Model Context Protocol) server for GraphQL that fixes real-world interoperability issues between LLMs and GraphQL APIs.

Drop-in replacement for mcp-graphql — with dynamic headers, robust variables parsing, and zero breaking changes.

💬 Community & Support

Join the conversation! If you have questions about using this bridge with Neo4j, Discord data graphs, or GraphQL in general, come hang out with us:

• Discord Channel: #mcp-graphql-enhanced
• Server: The official GraphQL Discord

This is the best place to share your feedback, report issues, or suggest new "enhanced" features for the bridge.

✨ Key Enhancements

• ✅ Built-in GraphiQL IDE — Visual playground at http://localhost:MCP_PORT/ (or /graphiql) with pre-configured headers.
• ✅ Dual Transport — Supports both STDIO (for local CLI/client tools) and HTTP/JSON-RPC (for external/browser clients).
• ✅ Dynamic headers — pass Authorization, X-API-Key, etc., via tool arguments (no config restarts)
• ✅ Robust variables parsing — fixes “Query variables must be a null or an object” error
• ✅ Filtered introspection — request only specific types (e.g., typeNames: ["Query", "User"]) to reduce LLM context noise
• ✅ Full MCP compatibility — works with Claude Desktop, Cursor, Glama
• ✅ Secure by default — mutations disabled unless explicitly enabled
• ✅ Dynamic Schema Evolution — Smart diagnostics and gap analysis for servers that regenerate GraphQL types on-the-fly (like Neo4j).
• ✅ Deep Observability — Automatic Cypher extraction and cleaning from GraphQL extensions.

🚀 Federated Multi-Node Architecture (v3.9.1+)

The server operates as a Federated GraphQL Gateway, merging independent nodes into a unified system.

• Zero Breaking Changes: If you provide a single URL in ENDPOINT, the server behaves exactly as before.
• Federated Introspection: Scans all endpoints simultaneously to build a global capability map.
• Smart Aggregation: When multiple comma-separated URLs are provided, the server broadcasts queries and merges results using universal deep deduplication (object-level).
• Conflict Handling: Identifies structural differences in identical Type names across nodes and exposes them uniquely.
• Bypass Free Tier Limits: Perfect for users of "Free Tier" cloud databases (like Neo4j Aura). You can split your data across multiple free instances and use this bridge to query them as a single unified graph, effectively bypassing entity count limitations.

💡 Use Case: Bridging WSL and Windows (PowerShell)

A common challenge for Windows developers is the network isolation between the Windows Subsystem for Linux (WSL) and the host OS. This feature allows you to bridge these two worlds into a "Unified Nervous System".

Example configuration for Claude Desktop:

{
  "ENDPOINT": "http://DESKTOP-NAME.local:2311/graphql,http://127.0.0.1:4000/graphql"
}

• Hybrid Ecosystem: Seamlessly query and aggregate data across Windows-native processes (PowerShell) and Linux-based environments (WSL).

• mDNS Support: By using .local addresses, the bridge automatically resolves the host machine's IP from within the WSL environment.

• Transparent Aggregation: The AI assistant interacts with a single unified schema, unaware that the data is being fetched from different operating systems simultaneously.

🔍 Advanced Observability & Cypher

The bridge provides deep insights into how the LLM interacts with your graph database.

🕸️ Automated Cypher Extraction

For GraphQL server implementations that return query execution plans (like @neo4j/graphql), the bridge automatically:

1. Detects extensions.cypher in the response.
2. Sanitizes the output by stripping internal headers (like CYPHER 5 or empty PARAMS).
3. Injects a clean Cypher block directly into the tool's output for the AI to analyze.

Note: This feature requires your GraphQL server to be configured to include debug information in the response extensions.

---

🎨 Visual Command Center (GraphiQL)

Unlike standard MCP servers, this one provides a visual interface for humans. When running with ENABLE_HTTP=true, you can open a full-featured GraphiQL IDE in your browser.

• Endpoint: http://localhost:6274/ (or /graphiql)
• Header Sync: Any headers set in your environment (like GitHub tokens) are automatically injected into the GraphiQL "Headers" tab for immediate testing.

💻 HTTP / Dual Transport

This server now runs in dual transport mode, supporting both the standard STDIO communication (used by most MCP clients) and a new HTTP JSON-RPC endpoint on port 6274.

This allows external systems, web applications, and direct curl commands to access the server's tools with live request logging in your terminal ([HTTP-RPC] logs).

Endpoint	Method	Description
/graphiql	GET	Human Interface: The visual GraphQL IDE.
/mcp	POST	The main JSON-RPC 2.0 endpoint for tool execution.
/health	GET	Simple health check, returns { status: 'ok' }.

Automatic Port Selection

The server defaults to port 6274. If you encounter an EADDRINUSE error, the server will automatically find the next available port. Check the server logs for the final bound port (e.g., [HTTP] Started server on http://localhost:6275).

Resolving Port Conflicts (EADDRINUSE) and Automatic Port Selection

The server defaults to port 6274. If you encounter an EADDRINUSE: address already in use :::6274 error (common in local development due to stale processes), the server will automatically find the next available port (up to 10 attempts, not spawning multiple servers).

This ensures the server starts successfully even when the default is blocked. Always check the server logs for the final bound port (e.g., [HTTP] Started server on http://localhost:6275) if your curl or client tool fails on the default 6274.

To force a specific port (e.g., for guaranteed external firewall settings), you can still explicitly set the MCP_PORT environment variable:

Testing the HTTP Endpoint

You can test the endpoint using curl as long as the server is running (e.g., via npm run dev):

# Test the health check (assuming the server bound to the default or found the next available port)
curl http://localhost:6274/health

# Example: Test the query tool via JSON-RPC (using port 6275 if 6274 was busy)
curl -X POST http://localhost:6275/mcp -H "Content-Type: application/json" -d '{"jsonrpc":"2.0","method":"query-graphql","params":{"query":"query { __typename }"},"id":1}'

## 🔍 Filtered Introspection
Avoid 50k-line schema dumps. Ask for only what you need:
`@introspect-schema typeNames ["Query", "User"]`
## 🔍 Debug & Inspect
Use the official MCP Inspector to test your server live:
```bash
npx @modelcontextprotocol/inspector \
  -e ENDPOINT=https://api.example.com/graphql \
  npx @letoribo/mcp-graphql-enhanced

Environment Variables (Breaking change in 1.0.0)

Note: As of version 1.0.0, command line arguments have been replaced with environment variables.

Environment Variable	Description	Default
ENDPOINT	GraphQL endpoint URL	https://mcp-neo4j-discord.vercel.app/api/graphiql
HEADERS	JSON string containing headers for requests	{}
ALLOW_MUTATIONS	Enable mutation operations (disabled by default)	false
NAME	Name of the MCP server	mcp-graphql-enhanced
SCHEMA	Path to a local GraphQL schema file or URL	-
MCP_PORT	Port for the HTTP/JSON-RPC server.	6274
ENABLE_HTTP	Enable HTTP transport: auto (default), true, or false	auto
DEBUG	Set to mcp:* for detailed SDK logs	-
Note on ENABLE_HTTP:

• auto (default): Automatically enables HTTP only when running in MCP Inspector...
• true: Always enable HTTP server
• false: Disable HTTP server completely

Examples

# Basic usage
ENDPOINT=http://localhost:3000/graphql npx @letoribo/mcp-graphql-enhanced
# With auth header
ENDPOINT=https://api.example.com/graphql \
HEADERS='{"Authorization":"Bearer xyz"}' \
npx @letoribo/mcp-graphql-enhanced
# Enable mutations
ENDPOINT=http://localhost:3000/graphql \
ALLOW_MUTATIONS=true \
npx @letoribo/mcp-graphql-enhanced
# Use local schema file
ENDPOINT=http://localhost:3000/graphql \
SCHEMA=./schema.graphql \
npx @letoribo/mcp-graphql-enhanced
# Change the HTTP port
MCP_PORT=8080 npx @letoribo/mcp-graphql-enhanced
# Disable HTTP transport (fastest, recommended for Claude Desktop)
ENABLE_HTTP=false npx @letoribo/mcp-graphql-enhanced
# Test the surgical precision and the IDE immediately:
ENDPOINT=https://api.github.com/graphql \
HEADERS='{"Authorization":"Bearer YOUR_GITHUB_TOKEN"}' \
ENABLE_HTTP=true \
npx @letoribo/mcp-graphql-enhanced

# Then visit http://localhost:6274/graphiql

🖥️ Claude Desktop Configuration Examples

You can connect Claude Desktop to your GraphQL API using either the npx package (recommended for simplicity) or the Docker image (ideal for reproducibility and isolation).

✅ Option 1: Using npx

{
  "mcpServers": {
    "mcp-graphql-enhanced": {
      "command": "npx",
      "args": ["@letoribo/mcp-graphql-enhanced"],
      "env": {
        "ENDPOINT": "https://your-api.com/graphql"
      }
    }
  }
}

🐳 Option 2: Using Docker (auto-pull supported)

{
  "mcpServers": {
    "mcp-graphql-enhanced": {
      "command": "sh",
      "args": [
        "-c",
        "docker run --rm -i -e ENDPOINT=$ENDPOINT -e HEADERS=$HEADERS -e ALLOW_MUTATIONS=$ALLOW_MUTATIONS ghcr.io/letoribo/mcp-graphql-enhanced:main"
      ],
      "env": {
        "ENDPOINT": "https://your-api.com/graphql",
        "HEADERS": "{\"Authorization\": \"Bearer YOUR_TOKEN\"}",
        "ALLOW_MUTATIONS": "false"
      }
    }
  }
}

🧪 Option 3: Using node with local build (for development)

If you’ve cloned the repo and built the project (npm run build → outputs to dist/):

{
  "mcpServers": {
    "mcp-graphql-enhanced": {
      "command": "node",
      "args": ["dist/index.js"],
      "env": {
        "ENDPOINT": "https://your-api.com/graphql",
        "ALLOW_MUTATIONS": "true"
      }
    }
  }
}

Resources

• graphql-schema: The server exposes the GraphQL schema as a resource that clients can access. This is either the local schema file, a schema file hosted at a URL, or based on an introspection query.

Available Tools

The server provides two main tools:

1. introspect-schema: This tool retrieves the GraphQL schema or a filtered subset (via typeNames). Use this first if you don't have access to the schema as a resource. This uses either the local schema file, a schema file hosted at a URL, or an introspection query. Filtered introspection (typeNames) is only available when using a live GraphQL endpoint (not with SCHEMA file or URL).
2. query-graphql: Execute GraphQL queries against the endpoint. By default, mutations are disabled unless ALLOW_MUTATIONS is set to true.

Security Considerations

Mutations are disabled by default to prevent unintended data changes. Always validate HEADERS and SCHEMA inputs in production. Use HTTPS endpoints and short-lived tokens where possible.

Customize for your own server

This is a very generic implementation where it allows for complete introspection and for your users to do whatever (including mutations). If you need a more specific implementation I'd suggest to just create your own MCP and lock down tool calling for clients to only input specific query fields and/or variables. You can use this as a reference.