Algorand

Algorand agents that check before they sign

On Algorand an account is lost in one field of an ordinary-looking transaction: a rekey hands its signing power to someone else, a close sends everything it holds. presign-guard reads every transaction in the group your agent is about to sign, simulates the group on a public node, and answers green, orange or red. Red is never signed, and what the agent sends counts toward limits you set.

What gets caught

Red, never signed: a rekey to another key, closing the account (all its ALGO to someone else), closing an asset holding to someone else while it still holds a balance, an asset called USDC or USDt that isn't Circle's 31566704 or Tether's 312769.
Orange, ask a person: a clawback transfer, opting in to an asset with a clawback address or frozen by default, an app being updated, deleted or cleared, an asset's control addresses handed over or cleared, giving up consensus participation for good, a fee far above normal, one transaction of a group sent without the rest, a group that would fail.
Simulated: the group runs on a public node first (algod simulate), which also says how much a close would send.
Intent: pass what the agent means to do (“pay 5 ALGO to the shop”), and a group that does something else is orange.
Your limits: ALGO paid counts toward an ALGO limit, USDC toward a USDC limit, other assets go to you for approval (Telegram or the wallet dashboard).

Before buying an asset

GET https://presign-guard.fizzl.eu/v1/token?chain=algorand&address=<asset id> ($0.01): fake USDC is red; a clawback, default-frozen holdings, an asset less than a day old, a few accounts holding most of the circulating supply and a thin market are orange. Circle's USDC comes back SAFE: no red flags, Circle's USDC.

Pick your setup

Setup	Package	What it guards
Your own code	`presign-guard-wallet`	`algorandSigner(signer, { any: true })` around an x402 AVM signer: ALGO payments, asset transfers, app calls and x402 payments in USDC
Claude and other MCP agents	`presign-guard-wallet-mcp`	Paying x402 APIs in USDC on Algorand (`ALGORAND_MNEMONIC`), kept to your limits
Vercel AI SDK, LangChain, Python	presign-guard-ai-sdk, fizzl-langchain, fizzl	A `check_algorand_transaction` tool the model calls before signing, and `check_token` with `chain: "algorand"`
Any agent with HTTP or MCP	presign-guard	`POST /v1/check` with `{"type": "algorand", "transaction": "<base64 msgpack>"}`, or a whole group as `transactions`; the same in the MCP tools

Your own code in a few lines

import { guardWallet } from 'presign-guard-wallet';
import { toClientAvmSigner } from '@x402/avm';
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { ExactAvmScheme } from '@x402/avm/exact/client';

const signer = toClientAvmSigner(process.env.AVM_PRIVATE_KEY);

// The agent's own Algorand account pays the $0.01 checks, capped per payment.
const checkPayer = new x402Client().setSpendControls({ maxAmountPerPayment: '$0.05' });
checkPayer.register('algorand:*', new ExactAvmScheme(signer));

const guarded = guardWallet(walletClient, {
  pay: wrapFetchWithPayment(fetch, checkPayer),
  limits: { tokens: { ALGO: { perTx: '10', perDay: '25' }, USDC: { perDay: '20' } } },
});
const algo = guarded.algorandSigner(signer, { any: true });

// Sign through algo instead of the raw signer: red is refused, orange asks, the limits apply.
const signed = await algo.signTransactions(groupBytes);

An x402 payment in USDC still takes the quick local path, without a check. guarded.pause() stops everything at once.

Cost

$0.01 per check, paid over x402 in USDC on Algorand (or Base, Solana, the XRP Ledger). Or prepaid: 100 checks for $0.80. The checks are free to try through the AI SDK, LangChain and Python tools: without a payer they answer with the free quick check, the verdict only.