Tool calling

ANTHROPIC_API_KEY=your-anthropic-key
AGENT_PRIVATE_KEY=0xYourTestnetAgentKey
AGENT_ALLOWED_RECIPIENTS=0xFirstAddress,0xSecondAddress

import { tool } from "ai";
import { z } from "zod";
import { BaseError, createPublicClient, createWalletClient, erc20Abi, formatEther, formatUnits, getAddress, http, isAddress, parseUnits } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { botChainTestnet } from "@uzolabs/sdk/chains";
import { getAddresses } from "@uzolabs/sdk/contracts";

const account = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY as `0x${string}`);
const publicClient = createPublicClient({ chain: botChainTestnet, transport: http() });
const walletClient = createWalletClient({ account, chain: botChainTestnet, transport: http() });
const { usdt } = getAddresses(botChainTestnet.id);
const explorer = botChainTestnet.blockExplorers.default.url;

// Rules the model cannot change. Keep them in code or config, never in the prompt.
const ALLOWED_RECIPIENTS = new Set((process.env.AGENT_ALLOWED_RECIPIENTS ?? "").split(",").filter((a) => isAddress(a)).map((a) => getAddress(a)));
const MAX_USDT_PER_TRANSFER = parseUnits("1", 6);

export const getBalances = tool({
  description: "Get the agent wallet's tBOT and USDT balances on BOT Chain testnet.",
  inputSchema: z.object({}),
  execute: async () => {
    const [native, usdtBalance] = await Promise.all([
      publicClient.getBalance({ address: account.address }),
      publicClient.readContract({ address: usdt, abi: erc20Abi, functionName: "balanceOf", args: [account.address] }),
    ]);
    return { address: account.address, tBOT: formatEther(native), USDT: formatUnits(usdtBalance, 6) };
  },
});

export const sendUsdt = tool({
  description: "Send USDT from the agent wallet to an approved recipient on BOT Chain testnet.",
  inputSchema: z.object({
    to: z.string().describe("Recipient address, 0x followed by 40 hex characters"),
    amount: z.string().regex(/^\d+(\.\d{1,6})?$/).describe("Amount in USDT, for example 0.5"),
  }),
  execute: async ({ to, amount }) => {
    // 1. Check the input against hard rules. Return errors as data so the model can explain them.
    if (!isAddress(to)) return { ok: false, error: "Not a valid address." };
    const recipient = getAddress(to);
    if (!ALLOWED_RECIPIENTS.has(recipient)) return { ok: false, error: "Recipient is not on the allowlist." };
    const value = parseUnits(amount, 6);
    if (value === 0n || value > MAX_USDT_PER_TRANSFER) return { ok: false, error: "Amount must be above 0 and at most 1 USDT." };
    const balance = await publicClient.readContract({ address: usdt, abi: erc20Abi, functionName: "balanceOf", args: [account.address] });
    if (value > balance) return { ok: false, error: `Not enough USDT. Balance: ${formatUnits(balance, 6)}` };

    // 2. Simulate first. A revert here costs nothing.
    let request;
    try {
      ({ request } = await publicClient.simulateContract({
        account,
        address: usdt,
        abi: erc20Abi,
        functionName: "transfer",
        args: [recipient, value],
      }));
    } catch (error) {
      const reason = error instanceof BaseError ? error.shortMessage : String(error);
      return { ok: false, error: `Simulation failed: ${reason.replace(/\s+/g, " ")}` };
    }

    // 3. Send and wait for the receipt. Always hand back a BOTScan link.
    const hash = await walletClient.writeContract(request);
    const receipt = await publicClient.waitForTransactionReceipt({ hash });
    return { ok: receipt.status === "success", hash, explorerUrl: `${explorer}/tx/${hash}` };
  },
});

import { anthropic } from "@ai-sdk/anthropic";
import { generateText, stepCountIs } from "ai";
import { getBalances, sendUsdt } from "./tools.ts";

const result = await generateText({
  model: anthropic("claude-sonnet-5-5"),
  system: [
    "You manage a USDT wallet on BOT Chain testnet.",
    "Check the balance before you send. Only send to addresses the user gives you.",
    "If a tool returns an error, explain it and do not retry.",
    "After a payment, give the amount, the recipient and the BOTScan link.",
  ].join("\n"),
  tools: { getBalances, sendUsdt },
  stopWhen: stepCountIs(8), // At most 8 model steps per request
  prompt: process.argv[2] ?? "What's my balance?",
});

for (const step of result.steps) {
  for (const call of step.toolCalls) console.log(`> ${call.toolName} ${JSON.stringify(call.input)}`);
  for (const output of step.toolResults) console.log(`< ${JSON.stringify(output.output)}`);
}
console.log(result.text);