Gemini-MCP-CLI

MCP Gemini Chat CLI 💬

A simple command-line interface (CLI) chat application powered by Google's Gemini model that acts as an MCP (Model Context Protocol) host.

✨ Features

• 🤖 Gemini Powered: Uses the Gemini API (gemini-2.0-flash-001 by default) for conversational responses.
• 🔌 MCP Host & Client: Connects to and leverages tools from multiple MCP servers.
• 🔎 Dynamic Tool Discovery: Automatically discovers available tools from connected servers.
• ⚡ Runtime Server Management: Add new MCP servers dynamically while the chat app is running using the add_server command.

🛠️ Prerequisites

• 🐍 Python 3.10+
• 📦 uv (or pip) for package management.
• 🔑 Google Gemini API Key.

🚀 Quick Start

1. Clone & Enter Directory:

   git clone <your-repo-url> # Replace <your-repo-url> with the actual repo URL
   cd mcp-gemini-chat
   

2. Create Virtual Environment & Activate:

   uv venv
   # On Linux/macOS
   source .venv/bin/activate
   # On Windows
   # .venv\Scripts\activate
   

3. Install Dependencies:
   (Installs mcp, google-genai, python-dotenv, httpx)

   uv pip install -r requirements.txt
   

4. Configure API Key: ⚠️ Replace YOUR_GEMINI_API_KEY with your actual key!

   echo "GEMINI_API_KEY=YOUR_GEMINI_API_KEY" > .env
   

5. Run the App: (Optionally specify MCP server scripts to connect on startup)

   # Example assuming the app script is in a 'src' directory
   python src/mcp_chat_app.py [path/to/server1.py] [path/to/server2.py]
   
   # Example without servers at startup
   # python src/mcp_chat_app.py
   

🌊 Flow of Calls

Basic Chat Flow (No Tools)

👤 User Input → 🤖 MCP Gemini Chat App → ✨ Gemini API → 🖥️ Display to User

Tool Usage Flow (e.g., Calculator, Weather)

1. 👤 User Input → 🤖 MCP Gemini Chat App → ✨ Gemini API
2. ✨ Gemini decides to use a tool → 🔌 MCP Client → ⚙️ MCP Server (e.g., Calculator Server)
3. ⚙️ Server executes the tool → 📄 Returns result → 🔌 MCP Client
4. 📄 Result → ✨ Gemini API → 🤔 Synthesizes final response
5. 🗣️ Final response → 🖥️ Display to User

▶️ Usage Guide

Running the Application

Start the application script, optionally providing paths to MCP server scripts you want to connect to immediately.

# Start without any initial servers
python src/mcp_chat_app.py

# Start and connect to specific servers
python src/mcp_chat_app.py mcp_server_weather.py mcp_server_calc.py

Adding MCP Servers

You can add more tools by connecting to more MCP servers:

1. At Startup:
Provide the paths to your server scripts as command-line arguments when starting mcp_chat_app.py:

python src/mcp_chat_app.py path/to/mcp_server_weather.py path/to/mcp_server_calc.py

2. At Runtime:
Use the add_server command within the chat interface:

You: add_server path/to/my_other_server.py

The application will attempt to connect and integrate the tools from the new server.

Example Session

$ python src/mcp_chat_app.py mcp_server_calc.py
# ... Initialization logs ...
MCP Gemini Chat App
Enter your message, 'add_server <path>' to add a server, or 'quit' to exit.

You: hi
Gemini: Hello! How can I help you today?

You: what is 5 plus 12?
# ... Tool call logs ...
Gemini: 5 plus 12 is 17.0.

You: add_server mcp_server_weather.py
# ... Connection and tool discovery logs ...
Gemini: Successfully added server 'mcp_server_weather.py' with tools: ['get_alerts', 'get_forecast']

You: any weather alerts in London?
# ... Tool call logs ...
Gemini: # ... (Response about weather alerts in London) ...

You: quit
# ... Cleanup logs ...
$