OpenRouter MCP Multimodal Server

Instructions

Implementation Reference

• src/tool-handlers/chat-completion.ts:11-35 (handler)

  The handler function that executes the chat completion logic using the OpenAI client.

  export async function handleChatCompletion(
    request: { params: { arguments: ChatCompletionToolRequest } },
    openai: OpenAI,
    defaultModel?: string,
  ) {
    const { messages, model, temperature, max_tokens } = request.params.arguments;
  
    if (!messages?.length) {
      return { content: [{ type: 'text', text: 'Messages array cannot be empty.' }], isError: true };
    }
  
    try {
      const completion = await openai.chat.completions.create({
        model: model || defaultModel || 'nvidia/nemotron-nano-12b-v2-vl:free',
        messages,
        temperature: temperature ?? 1,
        ...(max_tokens && { max_tokens }),
      });
  
      return { content: [{ type: 'text', text: completion.choices[0].message.content || '' }] };
    } catch (error: unknown) {
      const msg = error instanceof Error ? error.message : String(error);
      return { content: [{ type: 'text', text: `API error: ${msg}` }], isError: true };
    }
  }

• src/tool-handlers.ts:46-72 (registration)

  Tool registration with schema definition for 'chat_completion'.

  {
    name: 'chat_completion',
    description: 'Send messages to an OpenRouter model and get a response',
    inputSchema: {
      type: 'object',
      properties: {
        model: { type: 'string', description: 'Model ID (optional, uses default)' },
        messages: {
          type: 'array',
          minItems: 1,
          items: {
            type: 'object',
            properties: {
              role: { type: 'string', enum: ['system', 'user', 'assistant'] },
              content: {
                oneOf: [{ type: 'string' }, { type: 'array', items: { type: 'object' } }],
              },
            },
            required: ['role', 'content'],
          },
        },
        temperature: { type: 'number', minimum: 0, maximum: 2 },
        max_tokens: { type: 'number', minimum: 1 },
      },
      required: ['messages'],
    },
  },

• src/tool-handlers.ts:136-141 (registration)

  Execution dispatch for the 'chat_completion' tool in the request handler.

  case 'chat_completion':
    return handleChatCompletion(
      wrapToolArgs(args as ChatCompletionToolRequest | undefined),
      this.openai,
      this.defaultModel,
    );