base-gasless-deploy-mcp

Instructions

Implementation Reference

• src/index.ts:376-438 (handler)

  The complete implementation of the 'transfer_tokens' tool handler, including input validation schema, transaction estimation, and execution logic.

  server.tool(
    "transfer_tokens",
    "Transfer ERC-20 tokens gaslessly via paymaster. Falls back to normal gas if no paymaster. Requires DEPLOYER_PRIVATE_KEY (transfers FROM the deployer wallet).",
    {
      token_address: z.string().describe("Token contract address"),
      to: z.string().describe("Recipient address"),
      amount: z.string().describe("Amount in human units (e.g. '1000' for 1000 tokens)"),
    },
    async ({ token_address, to, amount }) => {
      try {
        const signer = getSigner();
        const provider = getProvider();
        const token = new ethers.Contract(token_address, TOKEN_ABI, signer);
  
        // Get decimals
        const decimals = await token.decimals();
        const amountWei = ethers.parseUnits(amount, decimals);
  
        // Check balance
        const signerAddress = await signer.getAddress();
        const balance = await token.balanceOf(signerAddress);
        if (balance < amountWei) {
          return mcpError(
            `Insufficient balance. Have: ${ethers.formatUnits(balance, decimals)}, Need: ${amount}`
          );
        }
  
        // Estimate gas for savings calc
        const gasEstimate = await token.transfer.estimateGas(to, amountWei);
        const feeData = await provider.getFeeData();
        const gasPrice = feeData.gasPrice || 0n;
        const estimatedCostWei = gasEstimate * gasPrice;
  
        // Encode the transfer call
        const txData = token.interface.encodeFunctionData("transfer", [to, amountWei]);
        const txRequest: ethers.TransactionRequest = {
          to: token_address,
          data: txData,
        };
  
        const { receipt, usedPaymaster } = await sendTransaction(signer, txRequest);
        const actualGasCostWei = receipt.gasUsed * receipt.gasPrice;
  
        return mcpResult({
          success: true,
          token_address,
          from: signerAddress,
          to,
          amount,
          decimals: Number(decimals),
          gasless: usedPaymaster,
          gas_used: receipt.gasUsed.toString(),
          gas_cost_eth: usedPaymaster ? "0 (sponsored)" : ethers.formatEther(actualGasCostWei),
          gas_saved_eth: usedPaymaster ? ethers.formatEther(estimatedCostWei) : "0",
          tx_hash: receipt.hash,
          block_number: receipt.blockNumber,
          explorer: `https://basescan.org/tx/${receipt.hash}`,
        });
      } catch (err: unknown) {
        const message = err instanceof Error ? err.message : String(err);
        return mcpError(`Transfer failed: ${message}`);
      }
    }