MCP RAG Server

An independent Model Context Protocol (MCP) server that exposes a search_documents tool. This server connects to a PostgreSQL database (pgvector) to perform semantic retrieval. It fetches relevant document snippets and returns the raw context directly to the calling Agent/LLM (e.g., OpenWebUI), so the client's LLM can perform the final synthesis.

Built with Python, FastAPI, and the official MCP SDK.

Project Structure

mcp-rag/
├── Dockerfile          # Hardened Alpine-based Docker image
├── README.md
├── requirements.txt    # Python dependencies
├── .env.example        # Environment variables template
└── src/
    ├── config.py       # Pydantic settings
    ├── rag.py          # Similarity search and retrieval logic
    └── server.py       # FastAPI MCP server definition

Related MCP server: Document Retrieval MCP Server

Setup & Configuration

1. Copy .env.example to .env and fill in your PostgreSQL connection details:

   cp .env.example .env

2. Make sure your POSTGRES_HOST is accessible from the container.

Running with Docker

This project provides a hardened Alpine-based Dockerfile.

1. Build the image:

   docker build -t mcp-rag-server .

2. Run the container:

   docker run -d \
     --name mcp-rag \
     --env-file .env \
     -p 8000:8000 \
     mcp-rag-server

The MCP Server will be accessible at http://localhost:8000/mcp. You can configure your MCP-compatible clients (like OpenWebUI) to connect via SSE to this endpoint.

Available MCP Tools

• search_documents(question: str, top_k: int = 5) -> str Executes a similarity search against the pgvector store and returns the raw text snippets and their citations. Does NOT perform LLM synthesis natively.