OpenRouter MCP Server

A Model Context Protocol (MCP) server providing seamless integration with OpenRouter.ai’s diverse model ecosystem. Access various AI models through a unified, type-safe interface with built-in caching, rate limiting, and error handling.

Features

• Model Access

  • Direct access to all OpenRouter.ai models
  • Automatic model validation and capability checking
  • Default model configuration support

• Performance Optimization

  • Smart model information caching (1-hour expiry)
  • Automatic rate limit management
  • Exponential backoff for failed requests

• Unified Response Format

  • Consistent ToolResult structure for all responses
  • Clear error identification with isError flag
  • Structured error messages with context

Installation

pnpm install @mcpservers/openrouterai

Configuration

Prerequisites

1. Get your OpenRouter API key from OpenRouter Keys
2. Choose a default model (optional)

Environment Variables

OPENROUTER_API_KEY=your-api-key-here
OPENROUTER_DEFAULT_MODEL=optional-default-model

Setup

Add to your MCP settings configuration file (cline_mcp_settings.json or claude_desktop_config.json):

{
  "mcpServers": {
    "openrouterai": {
      "command": "npx",
      "args": ["@mcpservers/openrouterai"],
      "env": {
        "OPENROUTER_API_KEY": "your-api-key-here",
        "OPENROUTER_DEFAULT_MODEL": "optional-default-model"
      }
    }
  }
}

Response Format

All tools return responses in a standardized structure:

interface ToolResult {
  isError: boolean;
  content: Array<{
    type: "text";
    text: string; // JSON string or error message
  }>;
}

Success Example:

{
  "isError": false,
  "content": [{
    "type": "text",
    "text": "{"id": "gen-123", ...}"
  }]
}

Error Example:

{
  "isError": true,
  "content": [{
    "type": "text",
    "text": "Error: Model validation failed - 'invalid-model' not found"
  }]
}

Available Tools

chat_completion

Send messages to OpenRouter.ai models:

interface ChatCompletionRequest {
  model?: string;
  messages: Array<{role: "user"|"system"|"assistant", content: string}>;
  temperature?: number; // 0-2
}

// Response: ToolResult with chat completion data or error

search_models

Search and filter available models:

interface ModelSearchRequest {
  query?: string;
  provider?: string;
  minContextLength?: number;
  capabilities?: {
    functions?: boolean;
    vision?: boolean;
  };
}

// Response: ToolResult with model list or error

get_model_info

Get detailed information about a specific model:

{
  model: string;           // Model identifier
}

validate_model

Check if a model ID is valid:

interface ModelValidationRequest {
  model: string;
}

// Response: 
// Success: { isError: false, valid: true }
// Error: { isError: true, error: "Model not found" }

Error Handling

The server provides structured errors with contextual information:

// Error response structure
{
  isError: true,
  content: [{
    type: "text",
    text: "Error: [Category] - Detailed message"
  }]
}

Common Error Categories:

• Validation Error: Invalid input parameters
• API Error: OpenRouter API communication issues
• Rate Limit: Request throttling detection
• Internal Error: Server-side processing failures

Handling Responses:

async function handleResponse(result: ToolResult) {
  if (result.isError) {
    const errorMessage = result.content[0].text;
    if (errorMessage.startsWith('Error: Rate Limit')) {
      // Handle rate limiting
    }
    // Other error handling
  } else {
    const data = JSON.parse(result.content[0].text);
    // Process successful response
  }
}

Development

See CONTRIBUTING.md for detailed information about:

• Development setup
• Project structure
• Feature implementation
• Error handling guidelines
• Tool usage examples

# Install dependencies
pnpm install

# Build project
pnpm run build

# Run tests
pnpm test

Changelog

See CHANGELOG.md for recent updates including:

• Unified response format implementation
• Enhanced error handling system
• Type-safe interface improvements

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.