Manifold Markets MCP Server

Instructions

Implementation Reference

• src/index.ts:608-648 (handler)

  Handler for place_bet tool: parses input with PlaceBetSchema, calls Manifold Markets /v0/bet API to place the bet, returns the result.

  case 'place_bet': {
    const params = PlaceBetSchema.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/bet`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Key ${apiKey}`,
      },
      body: JSON.stringify({
        contractId: params.marketId,
        amount: params.amount,
        outcome: params.outcome,
        limitProb: params.limitProb,
      }),
    });
  
    if (!response.ok) {
      throw new McpError(
        ErrorCode.InternalError,
        `Manifold API error: ${response.statusText}`
      );
    }
  
    const result = await response.json();
    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify(result, null, 2),
        },
      ],
    };
  }

• src/index.ts:58-63 (schema)

  Zod schema defining input parameters for the place_bet tool: marketId, amount, outcome (YES/NO), optional limitProb.

  const PlaceBetSchema = z.object({
    marketId: z.string(),
    amount: z.number().positive(),
    outcome: z.enum(['YES', 'NO']),
    limitProb: z.number().min(0.01).max(0.99).optional(),
  });

• src/index.ts:249-265 (registration)

  Tool registration in listTools response: defines name, description, and inputSchema for place_bet.

  {
    name: 'place_bet',
    description: 'Place a bet on a market',
    inputSchema: {
      type: 'object',
      properties: {
        marketId: { type: 'string', description: 'Market ID' },
        amount: { type: 'number', description: 'Amount to bet in mana' },
        outcome: { type: 'string', enum: ['YES', 'NO'] },
        limitProb: { 
          type: 'number',
          description: 'Optional limit order probability (0.01-0.99)',
        },
      },
      required: ['marketId', 'amount', 'outcome'],
    },
  },