Manifold Markets MCP Server

Instructions

Implementation Reference

• src/index.ts:861-898 (handler)

  Handler for the 'add_answer' tool: parses arguments with AddAnswerSchema, checks for API key, sends POST request to Manifold Markets API to add a new answer to the specified market, and returns success message with new answer ID.

  case 'add_answer': {
    const params = AddAnswerSchema.parse(args);
    const apiKey = process.env.MANIFOLD_API_KEY;
    if (!apiKey) {
      throw new McpError(
        ErrorCode.InternalError,
        'MANIFOLD_API_KEY environment variable is required'
      );
    }
  
    const response = await fetch(`${API_BASE}/v0/market/${params.contractId}/answer`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Key ${apiKey}`,
      },
      body: JSON.stringify({
        text: params.text,
      }),
    });
  
    if (!response.ok) {
      throw new McpError(
        ErrorCode.InternalError,
        `Manifold API error: ${response.statusText}`
      );
    }
  
    const result = await response.json();
    return {
      content: [
        {
          type: 'text',
          text: `Answer added with ID: ${result.newAnswerId}`,
        },
      ],
    };
  }

• src/index.ts:102-105 (schema)

  Zod schema defining the input parameters for the 'add_answer' tool: contractId (market ID) and text (answer text, min length 1).

  const AddAnswerSchema = z.object({
    contractId: z.string(),
    text: z.string().min(1),
  });

• src/index.ts:337-348 (registration)

  Registration of the 'add_answer' tool in the ListToolsRequestSchema handler, specifying name, description, and input schema matching AddAnswerSchema.

  {
    name: 'add_answer',
    description: 'Add a new answer to a multiple choice market',
    inputSchema: {
      type: 'object',
      properties: {
        contractId: { type: 'string', description: 'Market ID' },
        text: { type: 'string', description: 'Answer text' }
      },
      required: ['contractId', 'text']
    }
  },