langchain_mcp

This repository demonstrates a minimal working MCP (Multi-Server Control Plane) setup using LangChain, with:

• A dummy jobs and employee API (FastAPI)
• Two MCP servers (jobs and employee feedback)
• A Python client that can query either server

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Requirements

• Python 3.9+
• pip
• Node.js (optional, only if you want to build a frontend)
• An OpenAI API key (for GPT-4o)

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Setup

1. Clone the repository

git clone https://github.com/nishant-Tiwari24/mcp.git
cd mcp

2. Create and activate a virtual environment

python3 -m venv .venv
source .venv/bin/activate

Note: .venv is gitignored. You must create it yourself.

3. Install Python dependencies

pip install --upgrade pip
pip install -r requirements.txt

4. Set your OpenAI API key

Create a .env file in the project root (not tracked by git):

OPENAI_API_KEY=sk-...your-key-here...

Or export it in your shell before running the client:

export OPENAI_API_KEY=sk-...your-key-here...

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Running the Demo

1. Start the dummy jobs/employee API

uvicorn mcp_server.jobs_api:app --port 8001 --host 127.0.0.1

2. Start the MCP server (in a new terminal)

• For jobs server:

  python mcp_server/server.py
  

• For employee server:

  python mcp_server/server.py employee
  

Note: Only one MCP server can run at a time (always on port 8000).

3. Run the client (in a new terminal)

• Edit langchain_mcp_client.py and set SERVER = "jobs_server" or SERVER = "employee_server" at the top.
• Before running the client, make sure your OpenAI API key is exported:

  export OPENAI_API_KEY=sk-...your-key-here...
  python langchain_mcp_client.py
  

  Or, if you have a .env file, just run:

  python langchain_mcp_client.py
  

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File Structure

• langchain_mcp_client.py — Python client for querying MCP servers
• mcp_server/server.py — MCP server (jobs or employee feedback)
• mcp_server/jobs_api.py — Dummy FastAPI backend for jobs and employee data
• requirements.txt — Python dependencies
• .gitignore — Excludes .venv, .env, and other environment files

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Notes

• The .venv directory and .env file are not included in the repo. You must create them locally.
• Only the minimal, required files are tracked in git.
• If you want to add a frontend, you can do so separately (not included in this repo).

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Example Usage

• Jobs server:
  • Query: "I am looking for an AI engineer in San Jose, CA with 4-5 years of experience leveraging models like GPT 401, Claude 3.5 or similar. Can you please show the similar jobs I can use to create a requisition?"
• Employee server:
  • Query: "I am requesting a feedback summary for Kalyan P. The system will pull calendar year feedback, including Props, and create a summary for me to review, which can be ideally entered into Workday as an impact summary."

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License

MIT