Middleman

Middleman is an enterprise-grade Model Context Protocol (MCP) server designed to act as a "Signal Filter" between messy raw data and expensive LLMs. It gets another MCP output (e.g., Wikipedia) before going to the AI, summarizes it, and sends it to the AI to save tokens.

Real-World Impact

✨ Key Features

• Local File Processing: High-density distillation of local .txt, .log, and .md files.

• Surgical Focus Query: Tell Middleman exactly what you are looking for (e.g., "Focus only on the technical specs of the Starship engine") to ensure the summary is relevant.

• XML-Structured Output: Returns data in a strict <summary><core_facts>...</core_facts></summary> schema, optimized for machine-to-machine communication.

• Built on FastMCP: Robust, Pythonic implementation of the Model Context Protocol.

Related MCP server: mcp-compressor

🛠️ Technical Stack

🚀 Installation & Setup

1. Prerequisites

• Python 3.10 or higher https://github.com/JithunMethusahan/middleman

• An OpenRouter API Key

2. Clone and Install

git clone https://github.com/JithunMethusahan/middleman.git
cd middleman
python -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate
pip install -r requirements.txt![alt text](image.png)

3. Environment Configuration

Set your API key in your environment:

export OPENROUTER_API_KEY="your_key_here"
# Windows: $env:OPENROUTER_API_KEY="your_key_here"

4. Verify Connection:

Run the included benchmark to ensure the proxy and compressor are working:

python tests/experiment.py

4. Integration with Claude Desktop / Cursor

Add the following to your claude_desktop_config.json:

{
  "mcpServers": {
    "middleman": {
      "command": "/path/to/your/venv/bin/python",
      "args": ["/path/to/middleman/server.py"],
      "env": {
        "OPENROUTER_API_KEY": "sk-or-v1-..."
      }
    }
  }
}

5. Connecting Downstream Tools (The Proxy Gateway)

Middleman is a Universal Proxy. It does not come hardcoded with tools; instead, it "wraps" other MCP servers. You manage these connections via the servers.json file in the root directory.

1. Configure your Tools (servers.json)

Add any MCP-compatible server to this file. Middleman will automatically launch these in the background and intercept their data.

{
  "fetch": {
    "command": "python",
    "args": ["-m", "mcp_server_fetch"]
  },
  "sqlite": {
    "command": "uvx",
    "args": ["mcp-server-sqlite", "--db-path", "test.db"]
  }
}

2. How the AI uses the Gateway

The primary AI (Claude/Cursor) communicates with Middleman via the delegate_and_refine tool. This tool acts as the "Secure Pipe."

Tool Arguments:

1. target_server: The name defined in servers.json (e.g., "fetch").

2. target_tool: The actual tool name on that server (e.g., "fetch" or "query_db").

3. tool_kwargs_json: The arguments for the downstream tool in JSON format.

4. focus_query: The specific signal you want Middleman to extract from the resulting bloat.

3. Example Workflow

When you ask an AI to research a topic, the internal logic looks like this:

AI Call: delegate_and_refine

(target_server="fetch", target_tool="fetch", tool_kwargs_json='{"url": "https://wiki..."}', focus_query="Founding date")

Fetch Server: Downloads 15,000 tokens of raw Wikipedia HTML.

Middleman: Intercepts the 15,000 tokens..

Llama: Extracts the founding date into a 20-token XML block.meta-llama/llama-3.2-3b-instruct:free

AI Result: Receives only the 20-token XML. Token Savings: 99.8%.

Models you can use for free

1. 🦙 Meta (Llama Family)

Meta's open-source models are currently dominating the free tier

meta-llama/llama-3.3-70b-instruct:free (Top pick for general tasks)

meta-llama/llama-3.2-3b-instruct:free (Extremely fast, lightweight)

meta-llama/llama-3.1-405b:free (Huge model, slightly slower)

2. 🌐 Google

google/gemini-2.0-flash-exp:free (Massive 1-Million token context window)

3. 🧠 DeepSeek

deepseek/deepseek-r1:free (Best for deep logical thinking)

🤝 Contributing & Customization

Middleman is designed to be extensible. Want to add support for PDFs, YouTube transcripts, or SQL databases?

1. Fork the repo.

2. Add your tool to server.py.

3. Submit a Pull Request.

For custom enterprise integrations or consulting, contact the author via GitHub Issues.

📄 License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0