Futarchy MCP Server

Instructions

Implementation Reference

• src/mcp/server/index.ts:420-464 (registration)

  Full registration of the 'buyInFailMarket' MCP tool, including name, description, Zod input schema (proposalId: string, amount: number, user: string), and handler function that calls apiClient.buyInFailMarket and returns formatted response or error.

  server.tool(
    "buyInFailMarket",
    "Buy tokens in the fail market for a proposal",
    {
      proposalId: z.string().describe("The ID of the proposal to trade in"),
      amount: z.number().describe("Amount to buy"),
      user: z.string().describe("User's public key"),
    },
    async ({ proposalId, amount, user }) => {
      try {
        const response = await apiClient.buyInFailMarket(proposalId, amount, user);
        
        if (!response.success) {
          return {
            content: [
              {
                type: "text" as const,
                text: response.error || 'Unknown error',
              },
            ],
            isError: true,
          };
        }
        
        return {
          content: [
            {
              type: "text" as const,
              text: JSON.stringify(response.data, null, 2),
            },
          ],
        };
      } catch (error: any) {
        return {
          content: [
            {
              type: "text" as const,
              text: `Error buying in fail market: ${error.message || 'Unknown error'}`,
            },
          ],
          isError: true,
        };
      }
    }
  );

• src/mcp/server/index.ts:423-427 (schema)

  Zod schema for tool inputs: proposalId (string), amount (number), user (public key string).

  {
    proposalId: z.string().describe("The ID of the proposal to trade in"),
    amount: z.number().describe("Amount to buy"),
    user: z.string().describe("User's public key"),
  },

• src/mcp/server/index.ts:428-463 (handler)

  Handler function that executes the tool: calls apiClient.buyInFailMarket, checks success, returns JSON text response or error message.

  async ({ proposalId, amount, user }) => {
    try {
      const response = await apiClient.buyInFailMarket(proposalId, amount, user);
      
      if (!response.success) {
        return {
          content: [
            {
              type: "text" as const,
              text: response.error || 'Unknown error',
            },
          ],
          isError: true,
        };
      }
      
      return {
        content: [
          {
            type: "text" as const,
            text: JSON.stringify(response.data, null, 2),
          },
        ],
      };
    } catch (error: any) {
      return {
        content: [
          {
            type: "text" as const,
            text: `Error buying in fail market: ${error.message || 'Unknown error'}`,
          },
        ],
        isError: true,
      };
    }
  }

• src/mcp/common/api.ts:224-252 (helper)

  FutarchyApiClient helper method that proxies the buyInFailMarket action via HTTP POST to backend /proposals/{proposalId}/buy-fail endpoint.

  async buyInFailMarket(proposalId: string, amount: number, userPublicKey: string): Promise<Response> {
    try {
      const response = await fetch(`${this.baseUrl}/proposals/${proposalId}/buy-fail`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({
          amount,
          user: userPublicKey
        })
      });
  
      if (!response.ok) {
        throw new Error(`HTTP error! Status: ${response.status}`);
      }
      const data = await response.json();
      
      return {
        success: true,
        data: data
      };
    } catch (error: any) {
      return {
        success: false,
        error: error.message || 'Failed to buy in fail market'
      };
    }
  }