spawn-mcp

# MCP SSE Server POC A proof-of-concept server for STDIO transport of Model Context Protocol (MCP) into instant Server-Sent Events (SSE) streaming, deployable as a service. Instant remote hosted MCP servers with zero infrastructure work. ## Features - Create and manage MCP server configurations via a simple UI - Generate stable SSE endpoints for each configuration - Stream real-time model responses via SSE - Built with Express, Drizzle ORM, and PostgreSQL - One-click deployment on Render ## Local Development ### Prerequisites - Node.js (v18 or later) - PostgreSQL database ### Setup 1. Clone this repository: ```bash git clone https://github.com/yourusername/mcp-sse-poc.git cd mcp-sse-poc ``` 2. Install dependencies: ```bash npm install ``` 3. Set up your local PostgreSQL database and create a `.env` file with your database connection string: ``` DATABASE_URL=postgresql://username:password@localhost:5432/mcp_sse_db ``` 4. Generate and run migrations: ```bash npm run generate npm run migrate ``` 5. Start the development server: ```bash npm run dev ``` 6. Open your browser and navigate to `http://localhost:3000` ## Deployment on Render ### 1. Push Your Code to GitHub/GitLab Make sure your repository includes all the files in this project. ### 2. Create a Web Service on Render 1. Log in to your [Render Dashboard](https://dashboard.render.com/) 2. Click **New → Web Service** 3. Connect your GitHub/GitLab repository 4. Configure the service: - **Name**: Choose a name (e.g., `mcp-sse-poc`) - **Environment**: Node - **Build Command**: `npm install` (this will trigger the postinstall script that builds and migrates) - **Start Command**: `npm start` 5. Click **Create Web Service** ### 3. Add a PostgreSQL Database 1. In Render, click **New → PostgreSQL Database** 2. Name it (e.g., `mcp-sse-db`) 3. Select the free plan 4. Click **Create Database** 5. Copy the provided `DATABASE_URL` connection string ### 4. Configure Environment Variables 1. Go back to your Web Service 2. Navigate to the **Environment** tab 3. Add the following environment variable: - **Key**: `DATABASE_URL` - **Value**: Paste the connection string you copied ### 5. Deploy Render will automatically deploy your application. Once deployed, you can access it at the URL provided by Render. ## Usage 1. Open your deployed application in a browser 2. Create a new MCP server configuration by entering a name and JSON configuration 3. Save the configuration to generate an SSE URL 4. Use the SSE URL in your client application to stream model responses ### Example Configuration ```json { "mcpServers": { "playwright": { "command": "npx", "args": ["@playwright/mcp@latest"] } } } ``` ## Model Context Protocol (MCP) The Model Context Protocol is a lightweight, STDIO-based specification for interacting with language models over a standard input/output interface. It allows for real-time streaming of model responses and is designed to be simple and extensible. ### Core Concepts 1. **STDIO Transport** - Input: JSON blob describing context messages - Output: Incremental response tokens streamed to stdout - Errors & Events: Non-blocking notifications on stderr 2. **JSON Message Format** ```json { "context": [ { "role": "system", "content": "You are a helpful assistant." }, { "role": "user", "content": "Translate to French: Hello, world!" } ], "stream": true } ``` 3. **Server-Sent Events (SSE)** - Each JSON chunk becomes an SSE event - Perfect mapping to MCP's unidirectional streaming model ## License MIT