Gemini 2.5 Flash Image

A Model Context Protocol (MCP) server for conversational image generation and editing with Google's Gemini 2.5 Flash Image Preview. Designed to be easy to install and use from Claude Code and other MCP clients.

Key Features

• Text-to-Image: Generate images from detailed prompts
• Image Editing: Edit images with natural language instructions
• Multi-Image Composition / Style Transfer: Combine images or transfer styles
• File Save Option: Return base64 image and optionally save to file
• Provider-Agnostic MCP: Works in any MCP-enabled client

Requirements

• Node.js 18 or newer
• An MCP client (Claude Code, Cursor, VS Code, Windsurf, etc.)
• Google Gemini API Key: set GEMINI_API_KEY

Get a Gemini API key

Follow these steps to obtain an API key from Google AI Studio:

1. Open Google AI Studio and sign in: https://aistudio.google.com/apikey
2. Click “Create API key” (or “Manage keys” if you already have one)
3. Copy the generated key
4. Set it as an environment variable on your machine when running this server

Examples:

# macOS / Linux (bash/zsh)
export GEMINI_API_KEY="YOUR_API_KEY"

# Windows PowerShell
$env:GEMINI_API_KEY="YOUR_API_KEY"

Getting Started

First, install the MCP server with your client. The following examples center on Claude Code usage.

Standard config works in most tools:

{
  "mcpServers": {
    "gemini-2-5-flash-mcp": {
      "command": "npx",
      "args": ["@taiyokimura/gemini-2-5-flash-mcp@latest"]
    }
  }
}

Quick usage (Claude Code)

# npx（非対話フラグ付き） + APIキー同時指定（Claudeの -e 指定）
claude mcp add gemini-2-5-flash-mcp -s user -e GEMINI_API_KEY="YOUR_API_KEY" -- npx -y @taiyokimura/gemini-2-5-flash-mcp@latest

# グローバルインストール + APIキー同時指定（Claudeの -e 指定）
npm i -g @taiyokimura/gemini-2-5-flash-mcp \
  && claude mcp add gemini-2-5-flash-mcp -s user -e GEMINI_API_KEY="YOUR_API_KEY" -- gemini-2-5-flash-mcp

# HTTP モードで登録（SSE既定）例（対応クライアントのみ）
# ※ HTTP モードはこのプロセス自体がHTTPサーバとして常駐します
claude mcp add gemini-2-5-flash-mcp -s user \
  -e GEMINI_API_KEY="YOUR_API_KEY" \
  -e MCP_TRANSPORT="http" \
  -e MCP_HTTP_PORT="7801" \
  -e MCP_HTTP_PATH="/mcp" \
  -- npx -y @taiyokimura/gemini-2-5-flash-mcp@latest

Streamable HTTP mode（実験的）

STDIO の代わりに Streamable HTTP を使うこともできます。MCP クライアントが Streamable HTTP に対応している場合のみ利用してください。

1. サーバーを HTTP モードで起動

export MCP_TRANSPORT=http
export GEMINI_API_KEY=YOUR_API_KEY
# 任意（既定: 7801, /mcp, SSE）
export MCP_HTTP_PORT=7801
export MCP_HTTP_PATH=/mcp
export MCP_HTTP_ENABLE_JSON=false

npm run build
node ./build/index.js
# => HTTP transport listening on http://localhost:7801/mcp

2. クライアント側設定（例: Streamable HTTP対応クライアント）

• Type: HTTP (Streamable)
• URL: http://localhost:7801/mcp

注:

• SSE ストリーミングが既定。JSONレスポンスで使いたい場合は MCP_HTTP_ENABLE_JSON=true。
• セッションはサーバー側で生成（stateful）。完全 stateless にしたい場合はコード側で sessionIdGenerator: undefined に変更可能です。

claude mcp add gemini-2-5-flash-mcp -s user -- npx @taiyokimura/gemini-2-5-flash-mcp@latest

claude mcp remove gemini-2-5-flash-mcp

code --add-mcp '{"name":"gemini-2-5-flash-mcp","command":"npx","args":["@taiyokimura/gemini-2-5-flash-mcp@latest"]}'

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "gemini-2-5-flash-mcp": {
      "type": "local",
      "command": [
        "npx",
        "@taiyokimura/gemini-2-5-flash-mcp@latest"
      ],
      "enabled": true
    }
  }
}

Environment Variables

• GEMINI_API_KEY (required)
• GEMINI_IMAGE_ENDPOINT (optional) default: https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image-preview:generateContent
• MCP_NAME (optional, default: gemini-2-5-flash-mcp)

Available Tools

1. generate_image

Generate an image from a text prompt.

Parameters:

• prompt (required): Detailed description to generate
• saveToFilePath (optional): Path to save the image

Example input:

{
  "prompt": "Create a picture of a nano banana dish in a fancy restaurant with a Gemini theme",
  "saveToFilePath": "./gemini-native-image.png"
}

2. edit_image

Edit an image using a prompt.

Parameters:

• prompt (required): Edit instruction
• image (required): { dataBase64?: string, path?: string, mimeType?: string }
• saveToFilePath (optional)

Example input:

{
  "prompt": "Add a small, knitted wizard hat to the cat",
  "image": { "path": "./cat.jpeg", "mimeType": "image/jpeg" },
  "saveToFilePath": "./gemini-edited-image.png"
}

3. compose_images

Combine elements from multiple images.

Parameters:

• prompt (required)
• images (required): Array of image inputs (2-3 recommended)
• saveToFilePath (optional)

4. style_transfer

Transfer the style of one image to another.

Parameters:

• prompt (optional)
• baseImage (required)
• styleImage (required)
• saveToFilePath (optional)

Development

Run locally:

npm install
npm run build
npx .

Name Consistency & Troubleshooting

• Always use CANONICAL_ID (gemini-2-5-flash-mcp) for identifiers and keys.
• Use CANONICAL_DISPLAY (Gemini 2.5 Flash MCP) only for UI labels.
• Do not mix different names across clients.

Consistency Matrix:

• npm package name → gemini-2-5-flash-mcp
• Binary name → gemini-2-5-flash-mcp
• MCP server name (SDK metadata) → gemini-2-5-flash-mcp
• Env default MCP_NAME → gemini-2-5-flash-mcp
• Client registry key → gemini-2-5-flash-mcp
• UI label → Gemini 2.5 Flash MCP

Conflict Cleanup:

• Remove any old entries like "GeminiFlash" and re-add with gemini-2-5-flash-mcp.
• Ensure global registries only use gemini-2-5-flash-mcp for keys.
• Cursor: configure in the UI only. This project does not include .cursor/mcp.json.

References

• MCP SDK: https://modelcontextprotocol.io/docs/sdks
• Architecture: https://modelcontextprotocol.io/docs/learn/architecture
• Server concepts: https://modelcontextprotocol.io/docs/learn/server-concepts
• Server spec (2025-06-18): https://modelcontextprotocol.io/specification/2025-06-18/server/index
• Gemini image generation: https://ai.google.dev/gemini-api/docs/image-generation