Gemini MCP Server

MCP server that enables Claude Code to interact with Google's Gemini API directly.

Features

• gemini_analyze: Send prompts for code review, explanations, research
• gemini_chat: Multi-turn conversations with context
• gemini_summarize: Summarize large codebases/documents (1M token window)

Quick Start

# 1. Clone and build
git clone <this-repo> && cd gemini-mcp
npm install && npm run build

# 2. Set API key in ~/.zshrc
export GEMINI_API_KEY="your-key-here"
source ~/.zshrc

# 3. Add to ~/.claude.json (see config below)

# 4. Restart Claude Code

Setup

1. Get Gemini API Key

Get your free API key from: https://aistudio.google.com/apikey

2. Set Environment Variable

Add to your ~/.zshrc (or ~/.bashrc):

export GEMINI_API_KEY="your-api-key-here"

Then reload: source ~/.zshrc

3. Configure Claude Code

IMPORTANT: Add to ~/.claude.json, NOT ~/.claude/settings.json

Add this to the mcpServers object in ~/.claude.json:

{
  "mcpServers": {
    "gemini-mcp": {
      "type": "stdio",
      "command": "node",
      "args": ["/Users/buckmike/Projects/gemini-mcp/build/index.js"],
      "env": {
        "GEMINI_API_KEY": "${GEMINI_API_KEY}"
      }
    }
  }
}

Claude Code supports ${VAR} syntax for environment variable expansion.

4. Restart Claude Code

Exit and relaunch Claude Code to load the new MCP server.

Usage

Once configured, Claude can use these tools:

Tool	Purpose
gemini_analyze	Analyze code or answer questions using Gemini
gemini_chat	Have multi-turn conversations with context
gemini_summarize	Summarize large content (leverages 1M token window)

Available Models

Model	Description
gemini-2.5-flash-preview-05-20	Fast, efficient (default)
gemini-2.5-pro-preview-05-06	Best quality
gemini-2.0-flash	Stable release

Troubleshooting

Tools Not Appearing After Restart

Most Common Cause: Config in wrong file.

Wrong	Correct
~/.claude/settings.json	~/.claude.json

Claude Code reads MCP servers from ~/.claude.json, not the settings.json file in the .claude directory.

Verification Steps:

1. Check config location:

   cat ~/.claude.json | grep -A5 gemini-mcp
   

2. Verify API key is set:

   echo $GEMINI_API_KEY
   

3. Test server manually:

   echo '{"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}},"id":1}' | GEMINI_API_KEY="$GEMINI_API_KEY" node build/index.js
   

4. Restart Claude Code completely (exit and relaunch)

Security

• API key stored in environment variable, never in code
• All inputs validated before API calls
• Errors handled gracefully

Development

npm install      # Install dependencies
npm run build    # Compile TypeScript
npm run dev      # Watch mode for development