About MCP Server: Demo
MCP Server: Demo is a demonstration project for building MCP servers that query database information. It is intended for developers exploring Cloudflare MCPAgent, Durable Objects, and D1.
Key features
- 01D1 database queries
- 02SQL query tool
- 03Database schema introspection
- 04Durable Object server implementation
- 05SQL migrations and seed data
- 06Integration tests
Use cases
- 01Explore a database-backed MCP server
- 02Inspect database schema before querying
- 03Adapt the query tools to another database
MCP support
The MCP server exposes a SQL query tool and a schema-introspection tool to MCP clients. It uses Cloudflare MCPAgent and Durable Objects, with SSE as its transport.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
We haven’t collected a package or remote endpoint for this server. Follow the instructions in the project README.
Tools
Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.
Details
From the project READMEMCP Server: Demo
Overview
This repository serves as a demonstration of building an MCP (Model Context Protocol) server that can access and query actual database information. Uses
the @modelcontextprotocol/sdk library leveraging Cloudflare's MCPAgent to implement tools, manage resources, and a D1 database.
Features
Database
The project integrates with a D1 database (mcp-agent-d1-data) to retrieve data but you should be able to work with any database with some minor adjustments on the tools. Also included some niceties:
- Schema Management: SQL migration files (
up.sql,down.sql,seed.sql) in thedb/directory manage the database schema and seed data.
MCP Server (MyMCP)
The MyMCP class extends the McpAgent class from the @modelcontextprotocol/sdk library. It acts as the core server implementation, providing server sent events (SSE) as a foundational transport.
- Durable Object: The server is implemented as a Durable Object, which allows stateful interactions and long process operations. It also comes with hibernation built-in when idle.
Query Tool
The query tool is designed to interact with the database by providing an interface where the LLM can send SQL queries onto the database. Use with care in production environments and practice proper authorization safeguards.
Introspection Tool
The schema-introspection tool is particularly useful to help the LLM understand the structure of the database to produce a more accurate query design.
Integration Tests
Included integration tests in the tests/ directory to get started. Validate the functionality of the MCP server and its tools, or use the tests for TDD.
npm run test
Project Structure
📦 d1-mcp
├── package.json
├── README.md
├── tsconfig.json
├── vitest.config.js
├── worker-configuration.d.ts
├── wrangler.jsonc
├── db
│ ├── down.sql
│ ├── seed.sql
│ └── up.sql
├── public
│ └── index.html
├── src
│ ├── index.ts
│ ├── metadata.ts
│ ├── tools.ts
│ └── utils.ts
└── tests
├── index.test.ts
└── tsconfig.json
Getting Started
Prerequisites
- Node.js
- Cloudflare Workers CLI (
wrangler)
Installation
- Clone the repository.
- Install dependencies:
npm install
Development
- Start the development server:
npm run dev
Deployment
- Deploy to Cloudflare Workers:
npm run deploy
License
This project is licensed under the MIT License.
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.