Cosmo MCP Server - WunderGraph

Overview

The Cosmo MCP Server allows developers to integrate Cosmo into their modern LLM/AI supported IDEs. The implementation is running fully on the client side using STDIO. As such, the MCP Server requires no additional setup on your machine other than setting up the wgc CLI tool with an API key.

Installation

To install the MCP Server, you’ll need to create an API key and configure your IDE to use it.

1. Create a new API key

You can create an API key in Cosmo Studio.

2. Configure your IDE

Add the following configuration to your IDE’s settings. You’ll need to replace cosmo_<redacted> with your actual API key.

{
  "mcpServers": {
    "cosmo": {
      "command": "npx wgc",
      "args": ["mcp"],
      "env": {
        "COSMO_API_KEY": "cosmo_<redacted>"
      }
    }
  }
}

Useful Prompts

Here are some example prompts you can use to get started.

Setting the Context

For the whole conversation,
if not otherwise specified,
assume that we're always working in the context of the
Namespace "default"
and the Supergraph "mygraph".

Schema Exploration

Load the schema of the Supergraph and summarize the core features

Supergraph: mygraph
Namespace: default

Show me the core features of this Supergraph.

Find out which subgraphs are part of the Supergraph

Supergraph: mygraph
Namespace: default

Which subgraphs are part of this Supergraph?

Load the SDL of the Supergraph

Supergraph: mygraph
Namespace: default

Show me the schema for this Supergraph.

Explore sub-sections of the Supergraph schema

Supergraph: mygraph
Namespace: default

Show me the schema for the Employee type in this Supergraph.

Dream Query Workflow

Supergraph: mygraph
Namespace: default

Use the dream_query_workflow
to enable the following query
on this Supergraph:

query {
  employees {
    name
    department {
      name
    }
  }
}

The dream_query_workflow guides the AI model through the process of adding the necessary schema changes to your Subgraphs to enable a new use case in your Supergraph. It will find out which Subgraphs are best to modify, and it will verify that the changes are composable and backwards compatible.

Schema Change Proposal Workflow

Supergraph: mygraph
Namespace: default

Use the schema_change_proposal_workflow
to add the field "age: Int!"
to the "Employee" type
in this Supergraph.

This workflow is a sub-workflow of the dream_query_workflow. Instead of starting from a query, it starts with instructions on what specifically to change in the schema.

AI-assisted Router Configuration

Use the Router Config Reference to make changes to the Router config

Look into the cosmo_router_config_reference
and help me to configure a custom GraphQL endpoint
in my Router config: router.yaml

Use the Router Config Reference to enable WebSockets

Look into the cosmo_router_config_reference
and help me to enable WebSockets
in my Router config: router.yaml

Documentation Search

Use fulltext search on the documentation to enable specific features in the Router config

Look into the cosmo documentation
and help me to properly configure CORS
in my Router config: router.yaml

Use fulltext search on the documentation to understand the steps to publish a Subgraph

Look into the cosmo documentation
and explain to me the steps to publish a Subgraph.

All Available Tools (Reference)

The MCP server exposes several tools that an AI model can utilize:

Subgraph Management

• list_subgraphs: Lists all subgraphs registered in your Cosmo Platform instance.
  • Use Case: Discovering available subgraphs.
• get_subgraphs: Retrieves detailed information for specified subgraphs, including their GraphQL Schema Definition Language (SDL).
  • Use Case: Inspecting the schema or configuration of specific subgraphs.
• introspect_subgraph: Introspects a running subgraph endpoint to retrieve its current GraphQL schema.
  • Use Case: Fetching the latest schema directly from a subgraph instance, useful for verifying deployments or comparing against registered schemas.
• subgraph_verify_schema_changes: Validates proposed changes to a subgraph’s schema. It checks for valid GraphQL SDL, composition compatibility with other subgraphs, and potential breaking changes against client traffic (optional).
  • Use Case: Safely validating schema modifications before deployment.

Supergraph (Federated Graph) Management

• list_supergraphs: Lists all federated graphs (Supergraphs) in your Cosmo Platform instance, optionally filtered by namespace.
  • Use Case: Discovering available Supergraphs.
• fetch_supergraph: Fetches the composed schema (SDL and client schema) and configuration details for a specific Supergraph.
  • Use Case: Examining the structure and configuration of a Supergraph.
• fetch_supergraph_router_config: Retrieves the router configuration (e.g., for WunderGraph Cosmo Router) for a specific Supergraph.
  • Use Case: Obtaining the necessary configuration to run a compatible router instance.
• fetch_supergraph_subgraphs: Fetches a list of all subgraphs that are part of a specific Supergraph, including their individual schemas and routing information.
  • Use Case: Understanding the composition of a Supergraph and its constituent subgraphs.

Schema Evolution & Query Workflows

• schema_change_proposal_workflow: Generates a step-by-step guide or set of instructions for making a specific schema change to a Supergraph safely and effectively.
  • Use Case: Assisting developers in planning and executing schema changes.
• dream_query_workflow: Takes a desired GraphQL query and generates instructions on the necessary schema modifications across relevant subgraphs to support that query within a Supergraph.
  • Use Case: Streamlining the process of evolving the Supergraph schema to meet new data requirements expressed via GraphQL queries.
• verify_query_against_remote_schema: Validates a given GraphQL query against the schema of a deployed Supergraph in your Cosmo Platform instance.
  • Use Case: Checking if a query is valid before integrating it into an application.
• verify_query_against_in_memory_schema: Validates a given GraphQL query against a provided Supergraph schema string (e.g., a locally composed schema).
  • Use Case: Testing queries against local or proposed schema changes without needing a deployed Supergraph.

Supergraph Changelog

• supergraph_changelog: Fetches the changelog for a federated graph / Supergraph.
  • Use Case: Reviewing the history of schema changes and composition updates for a Supergraph.

Router Configuration Verification

• verify_router_config: Verifies a provided Cosmo Router configuration (JSON or YAML) for validity.
  • Use Case: Ensuring a proposed router configuration is syntactically correct and valid before deployment.
• cosmo_router_config_reference: Provides a reference for the Cosmo Router configuration.
  • Use Case: Understanding the syntax and structure of the Cosmo Router configuration.

Documentation Search

• search_docs: Searches the official WunderGraph Cosmo documentation for a given query.
  • Use Case: Finding relevant documentation pages for specific features, concepts, or troubleshooting steps.