Manifold Markets MCP Server

Instructions

Implementation Reference

• src/index.ts:438-528 (handler)

  The handler function for the 'create_market' tool. It parses input arguments using CreateMarketSchema, validates required fields based on outcomeType, converts description to TipTap format if necessary, makes a POST request to Manifold Markets API to create the market, and returns the URL of the created 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 input validation in the create_market handler.

  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:144-213 (registration)

  Registration of the 'create_market' tool in the ListTools response, including name, description, and JSON input schema.

  {
    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']
    }
  },