Integration Guide

Threshold Action Control is not currently supported by active/available infrastructure (e.g. testnets, TACo node clients). This page serves solely as a open source reference and blueprint.

Guide

The TACo SDK allows you to implement conditional signing for ERC-4337 (a.k.a Account Abstraction) UserOperations. In just a few minutes, you'll be able to:

• Define signing conditions – Specify rules that must be fulfilled before UserOperations can be signed

• Request signatures – Get signatures from the decentralized network when conditions are met

• Execute signed UserOperations – Use the aggregated signature to execute transactions via Account Abstraction

1. Installation

Install @nucypher/taco, @nucypher/taco-auth, and ethers with your favorite package manager:

npm install @nucypher/taco @nucypher/taco-auth ethers@5.7.2

2. Configuration

To run the code examples below, you will need a cohortId signing parameter. For development and testing, we provide publicly available testnet cohorts:

Network	Domain	Cohort ID	Chain ID	Description
Lynx	DEVNET	1	11155111	Development cohort

For production use, please contact us to have a dedicated cohort configured.

3. Define Signing Conditions (Admin Only)

Only the cohort admin can set conditions. The testnet cohort comes pre-configured with a time-based condition that allows signing after a certain timestamp.

Admins can set conditions on the contract easily:

import { conditions, domains, setSigningCohortConditions } from '@nucypher/taco';
import { ethers } from 'ethers';

// Connect with admin wallet (only admin can set conditions)
const signerProvider = new ethers.providers.Web3Provider(window.ethereum);

// Example: Define a time-based condition
const timeCondition = new conditions.base.time.TimeCondition({
  returnValueTest: {
    comparator: '>',
    value: Math.floor(Date.now() / 1000), // Current timestamp in seconds
  },
});

// Set conditions for your cohort (requires admin privileges)
await setSigningCohortConditions(
  signerProvider,
  domains.DEVNET,
  timeCondition,
  cohortId, // your cohort ID
  chainId,
  signerProvider.getSigner()
);

4. Request Signatures

Once conditions are set, you can request signatures for UserOperations that meet those conditions:

import { conditions, domains, signUserOp, initialize } from '@nucypher/taco';
import { UserOperation } from '@nucypher/shared';
import { ethers } from 'ethers';

// Initialize TACo library (required once per application)
await initialize();

// Set up provider
const ethProvider = new ethers.providers.JsonRpcProvider('https://ethereum-sepolia-rpc.publicnode.com');

const userOp: UserOperation = {
  sender: '0x...',
  nonce: 0,
  callData: '0x...',
  callGasLimit: 50000,
  // ... other UserOperation fields
};

const conditionContext = await conditions.context.ConditionContext.forSigningCohort(
  ethProvider,
  domains.DEVNET,
  1, // cohortId
  11155111 // chainId
);

const aaVersion = '0.8.0';

const signResult = await signUserOp(
  ethProvider,
  domains.DEVNET,
  1, // cohortId
  11155111, // chainId
  userOp,
  aaVersion,
  conditionContext,
);

console.log('Message Hash:', signResult.messageHash);
console.log('Aggregated Signature:', signResult.aggregatedSignature);

5. Execute with Signature

The aggregated signature can now be used to execute the UserOperation through an ERC-4337 bundler:

// Add the signature to your UserOperation
userOp.signature = signResult.aggregatedSignature;

// Submit to your ERC-4337 bundler
// The bundler will validate the signature against the multisig contract
const bundlerResponse = await bundlerClient.sendUserOperation(userOp);

// The multisig contract's isValidSig method is called automatically
// by the EntryPoint contract during UserOperation validation

The signature validation happens automatically when the bundler submits the UserOperation to the EntryPoint contract. The EntryPoint calls the account's validateUserOp function, which in turn verifies the signature using the multisig contract's isValidSig method.

Next Steps

• Advanced Conditions: See the Signing Object Conditions Guide for more complex condition examples

• Production Access: Contact us for a dedicated production cohort

• Examples: Check out example implementations

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