SchemaStore MCP Server

An MCP (Model Context Protocol) server for SchemaStore.org — search, browse, and retrieve JSON schemas from the SchemaStore catalog.

Built with .NET 10 and the official MCP C# SDK.

Quick Start — Use the Hosted Server

The SchemaStore MCP Server is publicly hosted at **https://mcp.schemastore.org**. No local setup required.

Visual Studio

Add a .mcp.json file to your solution root (or add it via Copilot Chat → Select Tools → +):

{
  "inputs": [],
  "servers": {
    "SchemaStore": {
      "url": "https://mcp.schemastore.org/",
      "type": "http",
      "headers": {}
    }
  }
}

Visual Studio Code

Create .vscode/mcp.json in your workspace (or use Command Palette → MCP: Add Server):

{
  "servers": {
    "SchemaStore": {
      "url": "https://mcp.schemastore.org/",
      "type": "http"
    }
  }
}

Any MCP Client

Point your client at https://mcp.schemastore.org/ using HTTP transport.

Tools

Running the Server

cd src/SchemaStoreMcpServer
dotnet run

The server starts on http://localhost:5189 by default (see Properties/launchSettings.json).

• MCP endpoint: POST / (Streamable HTTP transport)
• Legacy SSE: GET /sse + POST /message
• Health check: GET /health

Adding the MCP Server to Your Editor

Visual Studio (Solution-scoped)

Add a .mcp.json file to your solution root:

{
  "inputs": [],
  "servers": {
    "SchemaStoreMcpServer": {
      "url": "http://localhost:5189/",
      "type": "http",
      "headers": {}
    }
  }
}

Or use the UI: GitHub Copilot Chat → Select Tools (wrench icon) → + → set Type to http and URL to http://localhost:5189/.

Visual Studio Code

Create .vscode/mcp.json in your workspace:

{
  "servers": {
    "SchemaStoreMcpServer": {
      "url": "http://localhost:5189/",
      "type": "http"
    }
  }
}

Or use the Command Palette: MCP: Add Server → HTTP → http://localhost:5189/ → give it a name.

Any MCP Client (stdio transport alternative)

If you prefer stdio transport (no need to keep a server running), point your client at:

{
  "servers": {
    "SchemaStoreMcpServer": {
      "type": "stdio",
      "command": "dotnet",
      "args": ["run", "--project", "path/to/src/SchemaStoreMcpServer/SchemaStoreMcpServer.csproj"]
    }
  }
}

Note: The stdio transport requires adding .WithStdioServerTransport() to Program.cs instead of .WithHttpTransport().

Testing with GitHub Copilot

1. Start the server (dotnet run)
2. Open GitHub Copilot Chat in Agent mode
3. Click the Select Tools icon — you should see the three schema tools listed
4. Try a prompt like: "Search SchemaStore for Docker-related schemas"

Testing with .http Files

See the test/mcp-session.http file for manual HTTP testing in Visual Studio.

Workflow:

1. Run the server
2. Execute the initialize POST request
3. Copy the Mcp-Session-Id from the response headers
4. Paste it into @sessionId = ...
5. Execute the tool call requests

Architecture

src/SchemaStoreMcpServer/
├── Program.cs                      # DI, MCP server, health checks, HTTP transport
├── Models/
│   └── SchemaCatalogEntry.cs       # DTOs (name, description, fileMatch, url)
├── Services/
│   ├── ISchemaCatalogService.cs    # Interface
│   └── SchemaCatalogService.cs     # Singleton: fetch, search, lookup, pagination
├── BackgroundServices/
│   └── CatalogRefreshService.cs    # Refreshes catalog every 30 minutes
└── Tools/
    └── SchemaTools.cs              # MCP tool definitions

• The schema catalog is fetched from https://www.schemastore.org/api/json/catalog.json at startup and refreshed every 30 minutes.
• Search uses multi-term scoring across name (×10), description (×5), and fileMatch (×3).
• Thread-safe catalog refresh via volatile reference swap.

Requirements

• .NET 10 SDK