CoFHE Errors Package

Overview

When working with Solidity smart contracts, you’ve probably encountered cryptic error messages like:

Error: execution reverted: 0x118cdaa7
Transaction reverted without a reason string
execution reverted

You only get a 4-byte error selector (0x118cdaa7 here) with no readable message. The @fhenixprotocol/cofhe-errors package maps a selector back to the error name, signature, and source contract.

What's inside

53 custom errors from 13 contracts, as of package version 1.0.2
Complete error signatures with parameter types
Source contract information
CLI lookup tool
JavaScript/TypeScript API

Version 1.0.2 of the package was published in January 2026 and predates the current contracts. Its database does not include errors added since, such as NotOnAccessList, DecryptFunctionNotSupported, LengthMismatch, NotShared, UnexpectedSharer, and the ACPShareRegistry errors. It still lists OnlyAggregatorAllowed, which the TaskManager no longer raises. When the CLI reports Error not found for selector, look the selector up on the error reference, which is generated from the deployed contracts.

Quick start

No installation is required. Use npx to decode an error:

npx cofhe-errors 0x118cdaa7

Output:

Name:      OwnableUnauthorizedAccount
Selector:  0x118cdaa7
Signature: OwnableUnauthorizedAccount(address)
Source:    ACL
Inputs:    address

Installation (optional)

Only install if you need to import the error database programmatically in your code:

npm install @fhenixprotocol/cofhe-errors

yarn add @fhenixprotocol/cofhe-errors

pnpm add @fhenixprotocol/cofhe-errors

CLI usage

Decode an error selector

When you see “execution reverted: 0x…”, decode it:

npx cofhe-errors 0x118cdaa7

Search errors by name

Find errors when you know part of the error name:

npx cofhe-errors --name Permission

Output:

0x4c40eccb PermissionInvalid_IssuerSignature (ACL)
0x8e143bf7 PermissionInvalid_RecipientSignature (ACL)
0xcbd3a966 PermissionInvalid_Disabled (ACL)
0xed0764a1 PermissionInvalid_Expired (ACL)

List all known errors

Browse the complete error database:

npx cofhe-errors --list

JSON output

Get JSON output for scripting and automation:

npx cofhe-errors --json 0x118cdaa7

Output:

{
  "name": "OwnableUnauthorizedAccount",
  "selector": "0x118cdaa7",
  "signature": "OwnableUnauthorizedAccount(address)",
  "source": "ACL",
  "inputs": ["account"],
  "inputTypes": ["address"]
}

Programmatic API

JavaScript/TypeScript usage

const errors = require('@fhenixprotocol/cofhe-errors/errors.json');

// Find error by selector
const error = errors.find(e => e.selector === '0x118cdaa7');
console.log(`Error: ${error.name}`);
console.log(`Signature: ${error.signature}`);

// Search by name
const permissionErrors = errors.filter(e =>
  e.name.toLowerCase().includes('permission')
);

// Get all errors from a specific contract
const aclErrors = errors.filter(e => e.source === 'ACL');

TypeScript with types

import errors from '@fhenixprotocol/cofhe-errors/errors.json';

interface SolidityError {
  name: string;
  selector: string;
  signature: string;
  source: string;
  inputs: string[];
  inputTypes: string[];
}

const error = errors.find(e => e.selector === '0x118cdaa7') as SolidityError;

Error monitoring example

const errors = require('@fhenixprotocol/cofhe-errors/errors.json');

// Decode error from blockchain event
function decodeError(errorData) {
  const selector = errorData.slice(0, 10); // First 4 bytes
  const error = errors.find(e => e.selector === selector);

  if (error) {
    console.log(`Error: ${error.name}`);
    console.log(`Contract: ${error.source}`);
    console.log(`Signature: ${error.signature}`);
  }
}

Error coverage

Package version 1.0.2 includes errors from the following contracts. The counts reflect the contracts at the time of that release, not the contracts deployed today.

Contract	Error Count
TaskManager	16
ACL	8
SafeCast	4
ERC1967Utils	4
Errors	4
Ownable2StepUpgradeable	4
ECDSA	3
Strings	3
Common	2
UUPSUpgradeable	2
Address	1
FHE	1
PlaintextsStorage	1

How error selectors work

Solidity custom errors use a 4-byte selector computed as:

selector = keccak256("ErrorName(type1,type2,...)").slice(0, 4)

Example:

error OwnableUnauthorizedAccount(address account);

Becomes:

Signature: OwnableUnauthorizedAccount(address)
Selector: keccak256("OwnableUnauthorizedAccount(address)") = 0x118cdaa7...
First 4 bytes: 0x118cdaa7

Next steps

View the error reference, generated from the deployed contracts
Learn about common errors and troubleshooting
Review best practices for FHE development

Introduction

Core Concepts

Confidential Contracts

Examples

Reference

Overview

What's inside

Quick start

Installation (optional)

CLI usage

Decode an error selector

Search errors by name

List all known errors

JSON output

Programmatic API

JavaScript/TypeScript usage

TypeScript with types

Error monitoring example

Error coverage

How error selectors work

Next steps

​Overview

What's inside

​Quick start

​Installation (optional)

​CLI usage

​Decode an error selector

​Search errors by name

​List all known errors

​JSON output

​Programmatic API

​JavaScript/TypeScript usage

​TypeScript with types

​Error monitoring example

​Error coverage

​How error selectors work

​Next steps

Overview

Quick start

Installation (optional)

CLI usage

Decode an error selector

Search errors by name

List all known errors

JSON output

Programmatic API

JavaScript/TypeScript usage

TypeScript with types

Error monitoring example

Error coverage

How error selectors work

Next steps