DeFi Trading Agent MCP Server

Instructions

Implementation Reference

• src/toolService.js:471-543 (handler)

  Main handler for submit_gasless_swap tool: validates input, signs approval/trade EIP-712 messages using user private key, calls agService.submitGaslessSwap to submit to relayer API.

  async submitGaslessSwap(params) {
    const { quoteData } = params;
  
    if (!quoteData) {
      throw new Error("Quote data from gasless quote is required");
    }
  
    if (!this.userPrivateKey) {
      throw new Error(
        "User private key is required for gasless swap execution"
      );
    }
  
    try {
      console.log("🚀 Processing gasless swap...");
  
      // Prepare the submission data - extract chainId from trade domain
      const chainId =
        quoteData.trade?.eip712?.domain?.chainId || params.chainId;
      if (!chainId) {
        throw new Error("Chain ID not found in quote data or parameters");
      }
  
      const submissionData = {
        chainId: chainId,
      };
  
      // Sign approval if present
      if (quoteData.approval) {
        console.log("🔐 Signing gasless approval...");
        const signedApproval = await this.blockchain.signGaslessApproval(
          quoteData.approval
        );
        submissionData.approval = signedApproval;
        console.log("✅ Approval signed");
      }
  
      // Sign trade (always required)
      if (!quoteData.trade) {
        throw new Error("Trade data is required in gasless quote");
      }
  
      console.log("🔐 Signing gasless trade...");
      const signedTrade = await this.blockchain.signGaslessTrade(
        quoteData.trade
      );
      submissionData.trade = signedTrade;
      console.log("✅ Trade signed");
  
      // Submit to Aggregator gasless API
      console.log("📤 Submitting gasless swap to Agg...");
      const result = await this.agg.submitGaslessSwap(submissionData);
  
      return {
        message: "Gasless swap submitted successfully",
        data: result,
        nextSteps: [
          "1. Gasless swap has been submitted to relayer",
          "2. Monitor status using get_gasless_status tool",
          "3. No gas fees required - relayer handles execution",
          `4. Trade hash: ${result.tradeHash}`,
        ],
        gaslessInfo: {
          tradeHash: result.tradeHash,
          approvalSigned: !!submissionData.approval,
          tradeSigned: !!submissionData.trade,
          relayerHandled: true,
        },
      };
    } catch (error) {
      throw new Error(`Gasless swap submission failed: ${error.message}`);
    }
  }

• src/index.js:706-724 (schema)

  Input schema definition for the submit_gasless_swap tool, specifying required quoteData object and optional chainId.

  {
    name: TOOL_NAMES.SUBMIT_GASLESS_SWAP,
    description:
      "Submit a gasless swap by signing approval and trade messages (no gas fees required)",
    inputSchema: {
      type: "object",
      properties: {
        quoteData: {
          type: "object",
          description: "Quote data from get_gasless_quote",
        },
        chainId: {
          type: "integer",
          description: "Blockchain ID (optional if included in quoteData)",
        },
      },
      required: ["quoteData"],
    },
  },

• src/index.js:1146-1147 (registration)

  Tool dispatch/registration in MCP server request handler: maps tool name to toolService.submitGaslessSwap execution.

  case TOOL_NAMES.SUBMIT_GASLESS_SWAP:
    result = await toolService.submitGaslessSwap(args);

• src/services/agService.js:160-184 (helper)

  agService helper method: HTTP POST to aggregator API /api/swap/gasless/submit with signed swap data, handles response and errors.

  async submitGaslessSwap(swapData) {
    try {
      const response = await fetch(`${this.baseUrl}/api/swap/gasless/submit`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json'
        },
        body: JSON.stringify(swapData)
      });
      
      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 swap submission failed');
      }
      
      return data.data;
    } catch (error) {
      throw new Error(`Failed to submit gasless swap: ${error.message}`);
    }
  }

• src/constants.js:13-13 (registration)

  TOOL_NAMES constant mapping tool key to string name 'submit_gasless_swap' used in registration.

  SUBMIT_GASLESS_SWAP: "submit_gasless_swap",