DeFi Trading Agent MCP Server

Instructions

Implementation Reference

• src/toolService.js:433-469 (handler)

  Primary MCP tool handler: validates params, ensures taker address, delegates to AgService.getGaslessQuote, formats MCP response with next steps and gasless info

  async getGaslessQuote(params) {
    const { chainId, buyToken, sellToken, sellAmount } = params;
  
    if (!chainId || !buyToken || !sellToken || !sellAmount) {
      throw new Error(
        "Missing required parameters: chainId, buyToken, sellToken, sellAmount"
      );
    }
  
    // Add taker address if not provided (required for gasless quotes)
    const quoteParams = {
      ...params,
      taker: params.taker || this.userAddress,
    };
  
    if (!quoteParams.taker) {
      throw new Error("Taker address is required for gasless quotes");
    }
  
    const result = await this.agg.getGaslessQuote(quoteParams);
  
    return {
      message: "Gasless swap quote retrieved successfully",
      data: result,
      nextSteps: [
        "1. Review the quote details including approval and trade objects",
        "2. Use submit_gasless_swap tool to execute this gasless swap",
        "3. Both approval and trade signatures will be handled automatically",
      ],
      gaslessInfo: {
        hasApproval: !!result.approval,
        hasTrade: !!result.trade,
        approvalType: result.approval?.type,
        tradeType: result.trade?.type,
      },
    };
  }

• src/index.js:670-705 (schema)

  Input schema and metadata definition for the get_gasless_quote tool in MCP ListTools response

    name: TOOL_NAMES.GET_GASLESS_QUOTE,
    description:
      "Get executable quote for a gasless token swap with EIP-712 signature data",
    inputSchema: {
      type: "object",
      properties: {
        chainId: {
          type: "integer",
          description: "Blockchain ID (e.g., 8453 for Base)",
        },
        buyToken: {
          type: "string",
          description: "Contract address of token to buy",
        },
        sellToken: {
          type: "string",
          description: "Contract address of token to sell",
        },
        sellAmount: {
          type: "string",
          description: "Amount of sellToken in base units",
        },
        taker: {
          type: "string",
          description:
            "Address executing the trade (required for gasless quotes, uses USER_ADDRESS from env if not provided)",
        },
        slippageBps: {
          type: "integer",
          description:
            "Maximum acceptable slippage in basis points (optional, min: 30)",
        },
      },
      required: ["chainId", "buyToken", "sellToken", "sellAmount"],
    },
  },

• src/index.js:1142-1144 (registration)

  MCP server switch case registration that calls ToolService.getGaslessQuote

  case TOOL_NAMES.GET_GASLESS_QUOTE:
    result = await toolService.getGaslessQuote(args);
    break;

• src/services/agService.js:139-158 (helper)

  AgService helper: Makes HTTP request to aggregator's /api/swap/gasless/quote endpoint and handles response/error

  async getGaslessQuote(params) {
    try {
      const queryParams = new URLSearchParams(params);
      const response = await fetch(`${this.baseUrl}/api/swap/gasless/quote?${queryParams}`);
      
      if (!response.ok) {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }
      
      const data = await response.json();
      
      if (!data.success) {
        throw new Error(data.error || 'Gasless quote request failed');
      }
      
      return data.data;
    } catch (error) {
      throw new Error(`Failed to get gasless quote: ${error.message}`);
    }
  }

• src/constants.js:12-12 (registration)

  Tool name constant definition used for registration and dispatch

  GET_GASLESS_QUOTE: "get_gasless_quote",