Manifold Markets MCP Server

Instructions

Implementation Reference

• src/index.ts:438-527 (handler)

  Handler for the 'create_market' tool: parses input with Zod schema, validates parameters based on outcomeType, formats description if needed, and makes a POST request to Manifold Markets API to create the market.
  case 'create_market': { const params = CreateMarketSchema.parse(args); const apiKey = process.env.MANIFOLD_API_KEY; if (!apiKey) { throw new McpError( ErrorCode.InternalError, 'MANIFOLD_API_KEY environment variable is required' ); } // Validate required fields based on market type switch (params.outcomeType) { case 'BINARY': if (!params.initialProb) { throw new McpError( ErrorCode.InvalidParams, 'initialProb is required for BINARY markets' ); } break; case 'PSEUDO_NUMERIC': if (!params.min || !params.max || !params.initialValue) { throw new McpError( ErrorCode.InvalidParams, 'min, max, and initialValue are required for PSEUDO_NUMERIC markets' ); } break; case 'MULTIPLE_CHOICE': case 'POLL': if (!params.answers || !Array.isArray(params.answers)) { throw new McpError( ErrorCode.InvalidParams, 'answers array is required for MULTIPLE_CHOICE/POLL markets' ); } break; case 'BOUNTIED_QUESTION': if (!params.totalBounty) { throw new McpError( ErrorCode.InvalidParams, 'totalBounty is required for BOUNTIED_QUESTION markets' ); } break; } // Convert string description to TipTap format if needed if (typeof params.description === 'string') { params.description = { type: 'doc', content: [ { type: 'paragraph', content: [ { type: 'text', text: params.description } ] } ] }; } const response = await fetch(`${API_BASE}/v0/market`, { method: 'POST', headers: { 'Content-Type': 'application/json', Authorization: `Key ${apiKey}`, }, body: JSON.stringify(params), }); if (!response.ok) { const error = await response.text(); throw new McpError( ErrorCode.InternalError, `Manifold API error: ${error}` ); } const market = await response.json(); return { content: [{ type: 'text', text: `Created market: ${market.url}`, }], }; }
• src/index.ts:27-49 (schema)

  Zod schema used for parsing and validating the input parameters to the create_market tool.
  const CreateMarketSchema = z.object({ outcomeType: z.enum(['BINARY', 'MULTIPLE_CHOICE', 'PSEUDO_NUMERIC', 'POLL', 'BOUNTIED_QUESTION']), question: z.string(), description: z.union([ z.string(), z.object({ type: z.literal('doc'), content: z.array(z.any()), }) ]).optional(), closeTime: z.number().optional(), // Unix timestamp in milliseconds visibility: z.enum(['public', 'unlisted']).optional(), initialProb: z.number().min(1).max(99).optional(), min: z.number().optional(), max: z.number().optional(), isLogScale: z.boolean().optional(), initialValue: z.number().optional(), answers: z.array(z.string()).optional(), addAnswersMode: z.enum(['DISABLED', 'ONLY_CREATOR', 'ANYONE']).optional(), shouldAnswersSumToOne: z.boolean().optional(), totalBounty: z.number().optional(), groupIds: z.array(z.string()).optional(), });
• src/index.ts:144-212 (registration)

  Tool registration in the listTools handler, defining the name, description, and JSON inputSchema for the create_market tool.
  { name: 'create_market', description: 'Create a new prediction market', inputSchema: { type: 'object', properties: { outcomeType: { type: 'string', enum: ['BINARY', 'MULTIPLE_CHOICE', 'PSEUDO_NUMERIC', 'POLL', 'BOUNTIED_QUESTION'], description: 'Type of market to create' }, question: { type: 'string', description: 'The headline question for the market' }, description: { type: 'string', description: 'Optional description for the market' }, closeTime: { type: 'string', description: 'Optional. ISO timestamp when market will close. Defaults to 7 days.' }, visibility: { type: 'string', enum: ['public', 'unlisted'], description: 'Optional. Market visibility. Defaults to public.' }, initialProb: { type: 'number', description: 'Required for BINARY markets. Initial probability (1-99)' }, min: { type: 'number', description: 'Required for PSEUDO_NUMERIC markets. Minimum resolvable value' }, max: { type: 'number', description: 'Required for PSEUDO_NUMERIC markets. Maximum resolvable value' }, isLogScale: { type: 'boolean', description: 'Optional for PSEUDO_NUMERIC markets. If true, increases exponentially' }, initialValue: { type: 'number', description: 'Required for PSEUDO_NUMERIC markets. Initial value between min and max' }, answers: { type: 'array', items: { type: 'string' }, description: 'Required for MULTIPLE_CHOICE/POLL markets. Array of possible answers' }, addAnswersMode: { type: 'string', enum: ['DISABLED', 'ONLY_CREATOR', 'ANYONE'], description: 'Optional for MULTIPLE_CHOICE markets. Controls who can add answers' }, shouldAnswersSumToOne: { type: 'boolean', description: 'Optional for MULTIPLE_CHOICE markets. Makes probabilities sum to 100%' }, totalBounty: { type: 'number', description: 'Required for BOUNTIED_QUESTION markets. Amount of mana for bounty' } }, required: ['outcomeType', 'question'] }