OpenRouter MCP Multimodal Server

An OpenRouter MCP server with native vision, image generation, and smart image optimization in one package.

Access 300+ LLMs through OpenRouter via the Model Context Protocol, with first-class support for multimodal workflows: analyze images, generate images, and chat — using free or paid models.

Why This One?

Related MCP server: VRChat MCP OSC

Tools

Quick Start

Prerequisites

Get a free API key from openrouter.ai/keys.

Option 1: npx (no install)

{
  "mcpServers": {
    "openrouter": {
      "command": "npx",
      "args": ["-y", "@stabgan/openrouter-mcp-multimodal"],
      "env": {
        "OPENROUTER_API_KEY": "sk-or-v1-..."
      }
    }
  }
}

Option 2: Docker

{
  "mcpServers": {
    "openrouter": {
      "command": "docker",
      "args": [
        "run",
        "--rm",
        "-i",
        "-e",
        "OPENROUTER_API_KEY=sk-or-v1-...",
        "stabgan/openrouter-mcp-multimodal:latest"
      ]
    }
  }
}

Option 3: Global install

npm install -g @stabgan/openrouter-mcp-multimodal

Then add to your MCP config:

{
  "mcpServers": {
    "openrouter": {
      "command": "openrouter-multimodal",
      "env": {
        "OPENROUTER_API_KEY": "sk-or-v1-..."
      }
    }
  }
}

Option 4: Smithery

npx -y @smithery/cli install @stabgan/openrouter-mcp-multimodal --client claude

Configuration

Security notes

• analyze_image can read local files the Node process can read and can fetch HTTP(S) URLs. URL fetches block private/link-local/reserved IPv4 and IPv6 targets (SSRF mitigation) and cap response size; they are still server-side requests—avoid pointing at internal-only hosts you rely on staying private.

• generate_image save_path writes to disk wherever the process has permission; treat prompts and paths like shell input from the MCP client user.

Usage Examples

Chat

Use chat_completion to explain quantum computing in simple terms.

Analyze an Image

Use analyze_image on /path/to/photo.jpg and tell me what you see.

Find Vision Models

Use search_models with capabilities.vision = true to find models that can see images.

Generate an Image

Use generate_image with prompt "a cat astronaut on mars, digital art" and save to ./cat.png

Architecture

src/
├── index.ts              # Server entry point, env validation, graceful shutdown
├── tool-handlers.ts      # Tool registration and routing
├── model-cache.ts        # In-memory model cache (1hr TTL)
├── openrouter-api.ts     # OpenRouter REST client (native fetch)
└── tool-handlers/
    ├── chat-completion.ts   # Text & multimodal chat
    ├── analyze-image.ts     # Vision analysis pipeline
    ├── generate-image.ts    # Image generation
    ├── image-utils.ts       # Sharp optimization, format detection, fetch
    ├── search-models.ts     # Model search with filtering
    ├── get-model-info.ts    # Model detail lookup
    └── validate-model.ts    # Model existence check

Key design decisions:

• Native fetch for OpenRouter and image URLs (no axios / node-fetch dependency in this package)

• Lazy sharp loading — sharp is loaded on first image operation, not at startup

• Singleton model cache — shared across tool handlers with configurable TTL (default 1 hour)

• Bounded URL fetches — timeouts, size limits, redirect cap, and blocked private networks for image URLs

• Graceful error handling — tools return structured errors instead of crashing the server

• Process safety — uncaught exceptions and unhandled rejections exit the process (no zombie servers)

Development

git clone https://github.com/stabgan/openrouter-mcp-multimodal.git
cd openrouter-mcp-multimodal
npm install
cp .env.example .env  # Add your API key
npm run build
npm start

Run Tests

npm test

npm test runs unit tests only (fast, no API key). With OPENROUTER_API_KEY in .env, run npm run test:integration for live OpenRouter tests (slower; may time out on congested networks).

npm releases: This repo’s publish-npm job uses npm trusted publishing (GitHub Actions OIDC). The package on npmjs.com must list this repository and workflow publish.yml under Settings → Trusted publisher. No long-lived NPMJS_TOKEN is required for publish once that is configured.

npm run lint
npm run format:check

Docker Build

docker build -t openrouter-mcp .
docker run -i -e OPENROUTER_API_KEY=sk-or-v1-... openrouter-mcp

Multi-stage build: 345MB final image (Alpine + vips runtime only).

Compatibility

Works with any MCP client:

• Claude Desktop

• Cursor

• Kiro

• Windsurf

• Cline

• Any MCP-compatible client

License

MIT

Contributing

Issues and PRs welcome. Please open an issue first for major changes.