gemini-mcp

MCP server for Google Gemini image generation and editing — natural-language image creation via the Gemini API (Nano Banana / Nano Banana Pro models).

• npm: npmjs.com/package/@chrischall/gemini-mcp
• Source: github.com/chrischall/gemini-mcp

Setup

Option A — npx (recommended)

Add to .mcp.json in your project or ~/.claude/mcp.json:

{
  "mcpServers": {
    "gemini": {
      "command": "npx",
      "args": ["-y", "@chrischall/gemini-mcp"],
      "env": {
        "GEMINI_API_KEY": "your-api-key-here"
      }
    }
  }
}

Option B — from source

git clone https://github.com/chrischall/gemini-mcp
cd gemini-mcp
npm install && npm run build

Then add to .mcp.json:

{
  "mcpServers": {
    "gemini": {
      "command": "node",
      "args": ["/path/to/gemini-mcp/dist/index.js"],
      "env": {
        "GEMINI_API_KEY": "your-api-key-here"
      }
    }
  }
}

Or use a .env file in the project directory with GEMINI_API_KEY=\x3Cvalue>.

Getting your API key

1. Go to aistudio.google.com/apikey
2. Create an API key (requires a Google account)
3. Copy the key and set it as GEMINI_API_KEY

Note: Image generation requires a billing-enabled Google Cloud project.

Environment Variables

Tools

Models

Image Generation

Workflows

Generate a single image:

gemini_generate_image(prompt: "a red maple leaf on white background, studio photo")
→ returns path to saved PNG

Generate multiple variations:

gemini_generate_image(prompt: "a cartoon fox", count: 4, output_dir: "/tmp/foxes")
→ returns paths to 4 PNG files

Edit an existing image:

gemini_edit_image(prompt: "make the background blue", images: ["/path/to/image.png"])
→ returns path to edited PNG

Generate a consistent set (master + scenes):

gemini_generate_set(
  master_prompt: "a cartoon fox named Rusty, orange fur, blue scarf",
  scenes: ["Rusty waving hello", "Rusty eating an apple", "Rusty sleeping"]
)
→ returns paths to master + 3 scene images, all consistent

Generate variations of a concept:

gemini_generate_set(
  master_prompt: "minimalist logo for a coffee shop",
  count: 5
)
→ returns master + 5 variations

Notes

• output_dir per-call overrides $GEMINI_OUTPUT_DIR which overrides the current working directory
• inline: true returns image bytes directly in the response instead of writing to disk
• count and scenes are mutually exclusive in gemini_generate_set
• reference_mode: "chain" makes each scene reference the previous image (vs. all referencing master)
• Aspect ratios: 1:1, 16:9, 9:16, 4:3, 3:4, 2:3, 3:2, and others
• Image sizes: 1K, 2K, 4K
• Server logs to stderr only — stdout is reserved for JSON-RPC