How JOULE moves

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

interface IERC20 { function approve(address, uint256) external returns (bool); }

interface IVoltExchange {
    struct Quote { uint256 creditOut; uint256 usdgSpent; uint256 feeAtoms; uint256 fills; uint8 reason; }
    function getQuoteForCredit(uint256 creditOut, uint256 maxFills) external view returns (Quote memory);
    function getActivationQuote(uint256 usdgIn, uint256 maxFills)
        external view returns (Quote memory q, uint256 creditedAtoms, uint256 activationFeeAtoms);
    function buy(uint256 usdgIn, uint256 minCreditOut, address recipient, uint256 maxFills)
        external returns (uint256 creditOut, uint256 usdgSpent);
    function buyAndActivate(uint256 usdgIn, uint256 minCreditOut, bytes32 beneficiary, uint256 maxFills)
        external returns (uint256 creditOut, uint256 usdgSpent, uint256 activationId);
}

contract AgentTopUp {
    IVoltExchange public immutable grid;
    IERC20 public immutable usdg;

    constructor(IVoltExchange grid_, IERC20 usdg_) { grid = grid_; usdg = usdg_; }

    /// Buy `credit` JOULE (6 decimals) into this contract.
    /// Pass `minOut` from an off-chain quote: a same-tx quote gives no slippage protection.
    function topUp(uint256 credit, uint256 minOut) external {
        IVoltExchange.Quote memory q = grid.getQuoteForCredit(credit, 64);
        uint256 budget = q.usdgSpent + q.feeAtoms;      // fee is added on top of seller price
        usdg.approve(address(grid), budget);
        grid.buy(budget, minOut, address(this), 64);
    }

    /// Spend `usdgIn` and credit `agent`'s API balance directly (no fee on this path).
    function fundAgent(uint256 usdgIn, uint256 minOut, address agent) external {
        usdg.approve(address(grid), usdgIn);
        grid.buyAndActivate(usdgIn, minOut, bytes32(uint256(uint160(agent))), 64);
    }
}

import { createWalletClient, createPublicClient, http, pad } from "viem";
import { VoltExchangeAbi } from "./abi/VoltExchange";

const credit = 25_000_000n; // $25 of inference (6 decimals)
const q = await pub.readContract({
  address: EXCHANGE, abi: VoltExchangeAbi,
  functionName: "getQuoteForCredit", args: [credit, 64n],
});
const budget = q.usdgSpent + q.feeAtoms;
// approve USDG for `budget`, then:
await wallet.writeContract({
  address: EXCHANGE, abi: VoltExchangeAbi, functionName: "buy",
  args: [budget, (q.creditOut * 995n) / 1000n, account.address, 64n],
});

import { privateKeyToAccount } from "viem/accounts";

// The agent's own wallet. Load it from your secret store, never from source.
const account = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY as `0x${string}`);

const epoch = 1; // bump to rotate: the first use of a higher epoch revokes older keys
const message = `Voltio API key · chain 4663 · epoch ${epoch}`;
const signature = await account.signMessage({ message });

// sk-volt-<epoch>-<base64(signature bytes)>
const apiKey = `sk-volt-${epoch}-${Buffer.from(signature.slice(2), "hex").toString("base64")}`;

curl https://voltiodotso.app/api/v1/chat/completions \
  -H "Authorization: Bearer $VOLTIO_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-5",
    "messages": [{"role": "user", "content": "Plan my next three tool calls."}],
    "stream": false
  }'

curl https://voltiodotso.app/api/v1/key \
  -H "Authorization: Bearer $VOLTIO_KEY"

# {
#   "object": "key",
#   "address": "0xAgent…",
#   "balance": { "currency": "USD", "available": "41.27", "used": "8.73", "credited": "50.00" },
#   "rate_limit": { "requests_per_minute": 120, "concurrent": 8 }
# }