MCP Servers over Streamable HTTP — Step-by-Step Guide
📝 Read the full article here: MCP Servers over Streamable HTTP (Step-by-Step)
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This repository contains a complete, working example of how to build and run an MCP (Model Context Protocol) server using Python, mcp, and FastAPI. You’ll learn how to:
- Expose tools and functions over HTTP using the MCP protocol
- Connect those tools to AI assistants like Cursor
- Use streamable HTTP as the transport
- Mount multiple MCP servers in a FastAPI app
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📁 Folder Structure
.
├── docs/ # Diagrams and assets (e.g., mcp-client-server.png)
├── fastapi_example/ # Example mounting multiple MCP servers in FastAPI
│ ├── echo_server.py # A server exposing a simple echo tool
│ ├── math_server.py # A server exposing a math tool
│ └── server.py # FastAPI app that mounts both echo and math servers
├── .gitignore
├── .python-version # Python version (for tools like pyenv or uv)
├── pyproject.toml # Project config and dependencies
├── readme.md # You're here!
├── runtime.txt # Python runtime for platforms like Render
├── server.py # Basic standalone MCP server using Tavily search
├── uv.lock # Lockfile for uv dependency manager⸻
🛠 Quickstart
- Install uv (recommended Python package manager)
curl -LsSf https://astral.sh/uv/install.sh | sh- Install dependencies and set up environment
uv venv && source .venv/bin/activate
uv pip install -r pyproject.toml- Run the basic MCP server
This uses the Tavily API to expose a simple web_search tool.
uv run server.py- Run the FastAPI app with multiple MCP servers
uv run fastapi_example/server.pyThis will mount:
- http://localhost:8000/echo/mcp/
- http://localhost:8000/math/mcp/
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🧪 Debug with MCP Inspector
- Install CLI support
uv add 'mcp[cli]'- Launch the inspector
uv run mcp dev server.pyThen go to: http://localhost:6274/?MCP_PROXY_AUTH_TOKEN=...
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🔌 Connect to Cursor
In Cursor, add your MCP server under Chat Settings > MCP Servers: ``json { "mcpServers": { "tavily": { "url": "http://localhost:8000/mcp/" } } } ``
✅ Note: You must include the trailing / in the URL.
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