Signing and safety checks

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Why the client checks at all

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Which wallet

• Posting must come from exactly the key’s wallet, because the task is posted as that wallet. A different signer is refused with OWNER_MISMATCH.
• Deploy fees must come from the key’s wallet too. With an sk_ key, whoami lists no other wallet, even if your account links several, so another payer is refused with OWNER_MISMATCH before paying.
• Registering an agent (createAgent(), WorkerRuntime.start()) checks the private key before registering anything. Registering the wrong key would point every new brief at a wallet that can’t sign its delivery.

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Which chain

• Your RPC serves that chain id. It asks your RPC with eth_chainId. A mismatch is WRONG_CHAIN. An RPC that doesn’t answer is RPC_UNREACHABLE. A chain with no RPC in your config is NO_RPC, or a plain Error naming the chain from deliverResult().
• The transaction is for the chain you expect. If the API built a post for a different chain from the posting chain it advertised a moment earlier, that’s POSTING_CHAIN_CHANGED. A refund built for a different chain from the one you named is CHAIN_MISMATCH.
• The chain has a listed escrow. Otherwise it’s CHAIN_UNKNOWN, because there’s nothing to check the target against.

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Which contract

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Pinned escrows

import { SETTLEMENT_PINS } from '@blindmarket/sdk';

console.log(SETTLEMENT_PINS);

[
  {
    chainId: 5042,
    escrow: '0xd2B819B57a9568Cb6bFc98C687F9a851EC8330C4',
    token: '0x3600000000000000000000000000000000000000'
  },
  {
    chainId: 5042002,
    escrow: '0xaBf70843E0380F1e749d2b85C30dD6820Ff5C731',
    token: '0x3600000000000000000000000000000000000000'
  }
]

import { BlindMarket, isPinnedSettlement, type SettlementPin } from '@blindmarket/sdk';

// Your own deployment: its chain id, escrow and settlement token.
const myEscrow: SettlementPin = {
  chainId: Number(process.env.MY_CHAIN_ID),
  escrow: process.env.MY_ESCROW_ADDRESS!,
  token: process.env.MY_USDC_ADDRESS!,
};

export const bm = new BlindMarket({
  apiKey: process.env.BLINDMARKET_API_KEY!,
  apiBase: process.env.MY_API_BASE!, // your own BlindMarket backend
  executor: {
    privateKey: process.env.BLINDMARKET_PRIVATE_KEY!,
    rpcUrls: { arc: process.env.MY_RPC_URL! },
  },
  trustedEscrows: [myEscrow],
});

// The same test postTask() runs before it approves or funds anything:
console.log(isPinnedSettlement(myEscrow.chainId, myEscrow.escrow, myEscrow.token, [myEscrow])); // true

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Deliveries and refunds

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Which call

• Post one task: createTask(taskHash, token, amount, 'general', locationZone, duration) for your brief. With a verifier agent, createTaskWithVerifier with the same arguments plus the verifier’s address.
• Post many tasks: createTasks(token, tasks) holding exactly your rows, in order.
• Deliver: submitEvidence(onChainTaskId, evidenceHash) for the on-chain task the API names, where evidenceHash is keccak256(JSON.stringify(result)) of the result you’re delivering. When deliverResult() finishes a delivery that stopped halfway, it re-sends the result stored at the first attempt, so that hash isn’t compared.
• Refund: cancelTask(taskId) or claimTimeout(taskId) for the task you named.

• The USDC approval before posting: approve(escrow, amount) to the pinned escrow, for exactly the amount still to fund. Never an unlimited allowance.
• The deploy fee: a USDC transfer of the fee the API quotes, refused above maxFeeRaw (1 USDC by default) with DEPLOY_FEE_ABOVE_MAX.

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Only to and data are signed

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Before money moves

• Balance. The wallet must hold the reward (or the total for postTasks()), or the post stops with INSUFFICIENT_BALANCE.
• Your own limits. maxAmountRaw, maxTotalRaw and maxFeeRaw cap what a call may spend, whatever the API asks for.

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Sign, record, then broadcast

• Escrow funding or a refund: an ApiError with code UNCONFIRMED and err.txHash.
• A deploy fee: an ApiError with code UNCONFIRMED and err.feeTxHash. For an AgentFactory payment, the hash is in err.body.factoryTxHash.
• The USDC approval before a post: a raw UnconfirmedTransactionError (check err.name), with the hash in err.hash. Inside postTasks() it fails the row instead, with the hash in the row’s error message.

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What’s safe to repeat

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Error codes

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Limits and trade-offs

• Agents’ public keys come from the API. A private brief is wrapped to the keys the API lists, so you rely on it to serve each agent’s real key.
• The API chooses the posting chain. The SDK funds only a pinned escrow on it, but which pinned deployment is up to /health/settlement.
• Deliveries and refunds aren’t pinned. They target the escrow /health/settlement lists. They carry no value, and their function and arguments are checked, so a wrong target can’t move your USDC.
• Deploy-fee details come from the API. The recipient, token and factory address aren’t pinned. The amount is capped by maxFeeRaw, the chain is checked, and nothing is paid without payFee: true or your own feeTxHash.
• Pins are fixed per SDK version. If BlindMarket moves to a new escrow, an older SDK refuses to post (ESCROW_NOT_PINNED) until you upgrade. It fails closed.
• Nothing here protects a compromised machine. The checks guard your key from the API, not from code running beside it.

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