AABC-Labs-v1

import { Connection, Keypair, PublicKey, SystemProgram, Transaction } from '@solana/web3.js'import { createTransferCheckedInstruction, getAssociatedTokenAddress } from '@solana/spl-token'import bs58 from 'bs58' // X402 Payment Protocol Typesinterface PaymentRequirements {  maxAmountRequired: string // Atomic units (micro-USDC on mainnet, lamports on devnet)  asset: string // USDC mint address (mainnet) or 'SOL' (devnet)  description: string  resource: string} interface X402Payment {  x402Version: number  // v1.0 uses number 1, not string  scheme: string  network: string  payload: string // Base64 encoded transaction} // Initialize Solana connection (mainnet by default)const connection = new Connection(  process.env.SOLANA_RPC_URL || 'https://api.mainnet-beta.solana.com',  'confirmed')

1. Line 2 import { createTransferCheckedInstruction, getAssociatedTokenAddress } from '@solana/spl-t: A checked token transfer, which also verifies the mint and decimals.
2. Line 14 x402Version: number // v1.0 uses number 1, not string: Uses x402, an HTTP 402 pattern where an agent pays per request with an on-chain payment.

      )      const createTx = new Transaction().add(createIx)      createTx.feePayer = agent.publicKey      const createBlockhash = await conn.getLatestBlockhash('finalized')      createTx.recentBlockhash = createBlockhash.blockhash      createTx.sign(agent)       const createSig = await conn.sendRawTransaction(createTx.serialize(), { skipPreflight: false })      console.log('[Gateway] Create ATA transaction sent:', createSig)      await conn.confirmTransaction(createSig, 'confirmed')      console.log('[Gateway] Treasury token account created ✓')    }     // Per teacher's guidance (010.txt line 138-146):    // Only 1 transferChecked instruction, no Memo    const transferIx = createTransferCheckedInstruction(      agentAta,      new PublicKey(USDC),  // Must use mint address from accept.asset      destAta,      agent.publicKey,      priceAtomic,      6  // USDC decimals    )

1. Line 268 const createBlockhash = await conn.getLatestBlockhash('finalized'): Fetches a recent blockhash. Transactions expire if it gets too old.
2. Line 280 const transferIx = createTransferCheckedInstruction(: A checked token transfer, which also verifies the mint and decimals.

      const connection = new Connection(        process.env.NEXT_PUBLIC_SOLANA_RPC_URL || 'https://api.mainnet-beta.solana.com'      )       const fromTokenAccount = await getAssociatedTokenAddress(        USDC_MINT,        publicKey      )       const toTokenAccount = await getAssociatedTokenAddress(        USDC_MINT,        TREASURY_WALLET      )       const transaction = new Transaction().add(        createTransferInstruction(          fromTokenAccount,          toTokenAccount,          publicKey,          PRICE_USDC        )      )       const { blockhash } = await connection.getLatestBlockhash()

1. Line 52 createTransferInstruction(: An SPL token transfer through the Token Program.
2. Line 60 const { blockhash } = await connection.getLatestBlockhash(): Fetches a recent blockhash. Transactions expire if it gets too old.

    const usdcMint = new PublicKey(USDC_MINT);    const treasuryPubkey = new PublicKey(treasuryAddress);     const senderTokenAccount = await getAssociatedTokenAddress(      usdcMint,      publicKey    );     const recipientTokenAccount = await getAssociatedTokenAddress(      usdcMint,      treasuryPubkey    );     const transferInstruction = createTransferCheckedInstruction(      senderTokenAccount,      usdcMint,      recipientTokenAccount,      publicKey,      amountMicroUsdc,      USDC_DECIMALS    );     const { blockhash } = await connection.getLatestBlockhash('confirmed');    const transaction = new Transaction({

1. Line 98 const transferInstruction = createTransferCheckedInstruction(: A checked token transfer, which also verifies the mint and decimals.
2. Line 107 const { blockhash } = await connection.getLatestBlockhash('confirmed');: Fetches a recent blockhash. Transactions expire if it gets too old.