Agent Wallet MCP

Instructions

Implementation Reference

• src/index.ts:147-167 (handler)

  MCP tool handler for 'send_usdc': destructures arguments from request, invokes wallet.sendUsdc, and returns formatted success response with transaction explorer link.

  case "send_usdc": {
    const { recipient, amount, memo } = args as {
      recipient: string;
      amount: number;
      memo?: string;
    };
  
    const result = await wallet.sendUsdc(recipient, amount, memo);
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify({
            success: true,
            ...result,
            explorer: `https://explorer.solana.com/tx/${result.signature}?cluster=devnet`,
          }, null, 2),
        },
      ],
    };
  }

• src/index.ts:43-64 (registration)

  Registers the 'send_usdc' tool in the TOOLS list, including name, description, and input schema for MCP tool listing.

  {
    name: "send_usdc",
    description: "Send USDC to another Solana address. This executes a real transaction on Solana devnet.",
    inputSchema: {
      type: "object",
      properties: {
        recipient: {
          type: "string",
          description: "The Solana address to send USDC to",
        },
        amount: {
          type: "number",
          description: "Amount of USDC to send (e.g., 5.00 for $5)",
        },
        memo: {
          type: "string",
          description: "Optional memo/note for the transaction",
        },
      },
      required: ["recipient", "amount"],
    },
  },

• src/wallet.ts:138-206 (helper)

  Core implementation of USDC transfer: validates balance, creates associated token accounts if needed, builds SPL transfer transaction, and sends/confirms on Solana devnet.

  async sendUsdc(
    recipientAddress: string,
    amount: number,
    memo?: string
  ): Promise<TransactionResult> {
    const recipient = new PublicKey(recipientAddress);
    const sender = this.keypair.publicKey;
  
    // Get ATAs
    const senderAta = await getAssociatedTokenAddress(USDC_MINT, sender);
    const recipientAta = await getAssociatedTokenAddress(USDC_MINT, recipient);
  
    // Check sender has enough USDC
    try {
      const senderAccount = await getAccount(this.connection, senderAta);
      const balance = Number(senderAccount.amount) / Math.pow(10, USDC_DECIMALS);
      if (balance < amount) {
        throw new Error(`Insufficient USDC balance. Have: ${balance}, Need: ${amount}`);
      }
    } catch (error: any) {
      if (error.message?.includes("Insufficient")) {
        throw error;
      }
      throw new Error("No USDC token account found. Request devnet USDC first.");
    }
  
    // Build transaction
    const transaction = new Transaction();
  
    // Check if recipient ATA exists, if not create it
    try {
      await getAccount(this.connection, recipientAta);
    } catch {
      // Create recipient ATA
      transaction.add(
        createAssociatedTokenAccountInstruction(
          sender, // payer
          recipientAta, // ata address
          recipient, // owner
          USDC_MINT // mint
        )
      );
    }
  
    // Add transfer instruction
    const amountInBaseUnits = Math.floor(amount * Math.pow(10, USDC_DECIMALS));
    transaction.add(
      createTransferInstruction(
        senderAta,
        recipientAta,
        sender,
        amountInBaseUnits
      )
    );
  
    // Send transaction
    const signature = await sendAndConfirmTransaction(
      this.connection,
      transaction,
      [this.keypair]
    );
  
    return {
      signature,
      recipient: recipientAddress,
      amount,
      memo,
    };
  }