# Agent instructions

You are advising on UX and product design for **ERC-6093: Custom Errors for Common Tokens**.
This document is the authoritative designer guide from EIPs for Designers.

- Treat **MUST NOT** items as hard constraints unless the user explicitly overrides.
- Use the **Vocabulary** section for UI copy; do not use avoided terms.
- Cite the canonical source URL when giving recommendations.
- Use the official specification only for protocol implementation detail, not as primary UX guidance.

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# ERC-6093: Custom Errors for Common Tokens

Source: https://www.eipsfordesigners.com/standards/ERC-6093
Agent brief: https://www.eipsfordesigners.com/standards/ERC-6093/agent.md
Machine-readable JSON: https://www.eipsfordesigners.com/api/standards/ERC-6093
Last reviewed: 2026-04-05
Last updated: 2026-04-05

| Field | Value |
| --- | --- |
| Status | Final |
| Chain | both |
| Category | Comprehension & Display |
| Journey stages | Reading & Understanding |
| Detailed guide | Yes |
| Official specification | https://eips.ethereum.org/EIPS/eip-6093 |
| Discussion search | https://ethereum-magicians.org/search?q=ERC-6093 |

## UX Impact

Token errors become specific and actionable — 'Insufficient balance: have 50, need 100' instead of generic 'transfer failed'. Design implications: parse custom errors to show precise failure reasons, display relevant values (balances, allowances) in error messages, suggest fixes inline (e.g., 'Approve more tokens'). Design decisions: which error details to expose to users vs log internally, how to present technical info accessibly, fallback handling for non-standard errors, translating error codes to user-friendly language. Addresses the Blanket Warnings pain point (Medium severity, Unsolved) — identical warnings for routine and catastrophic actions train users to ignore all alerts. ERC-6093 enables contextual, specific error messages.

## Summary

ERC-6093 standardizes error messages for tokens. Instead of "execution reverted", you get "ERC20InsufficientBalance: have 5 USDC, need 10 USDC". Human-readable errors that explain exactly what went wrong and often how to fix it. This transforms cryptic failures into actionable feedback.

## For Designers

- You can design UI that delivers "ERC20InsufficientBalance(sender, balance, needed)".
- You can design UI that delivers "Need 10 more USDC. Current balance: 5 USDC".
- You can standard error signatures work everywhere.

## Applicability

### When to Use

- Your product addresses: error messages are unhelpful hex or generic text.
- Your users don't know how to fix failed transactions.
- The flow should deliver: "ERC20InsufficientBalance(sender, balance, needed)".
- You are designing a actionable error message experience with visible states and recovery paths.

### When to Avoid

- Decode and display human message.
- Parse error, show specific reason.
- Offer actions: "Approve more" or "Get tokens".
- Users never see addresses, amounts, or signing payloads in your UI.

## Problems It Solves

### Error messages are unhelpful hex or generic text

Impact: critical

Old way: "execution reverted" or "0x4e487b71..."

New way: "ERC20InsufficientBalance(sender, balance, needed)"

### Users don't know how to fix failed transactions

Impact: critical

Old way: "Transaction failed. Try again?" (why?)

New way: "Need 10 more USDC. Current balance: 5 USDC"

### Each token had different error formats

Impact: high

Old way: Parse custom errors for each protocol

New way: Standard error signatures work everywhere

## MUST NOT (Anti-Patterns)

- **Showing raw error hex to users** (critical)
  - Why: "0x4e487b71..." means nothing
  - Instead: Decode and display human message

- **Generic "Transaction failed" without details** (critical)
  - Why: User has no idea what went wrong
  - Instead: Parse error, show specific reason

- **No recovery suggestions** (high)
  - Why: User stuck, doesn't know next step
  - Instead: Offer actions: "Approve more" or "Get tokens"

## UX Patterns

### Actionable Error Message

Clear error with solution

User flow:

- Transaction reverts with custom error
- App decodes error using ERC-6093 ABI
- Extracts balance, needed amount
- Shows clear comparison
- Offers ways to resolve

Mockup registry key: `concept/verify-safety` (React UI on the live standard page).

### Approval Error

Handle insufficient allowance clearly

User flow:

- Swap fails with allowance error
- Decode ERC20InsufficientAllowance
- Show current vs needed
- One-click approve more
- Retry original action

Mockup registry key: `generic/token-approval` (React UI on the live standard page).

## UI Components

### ErrorDecoder

Parses ERC-6093 errors into readable format
States: parsing, decoded, unknown
Props: errorData, onDecode

### BalanceErrorCard

Shows balance shortfall with context
States: insufficient-balance, insufficient-allowance
Props: have, need, token, actionSuggestions

### ErrorRecoveryActions

Buttons to resolve the error
States: ready, resolving, resolved
Props: actions[], onAction

## On Monad

### Error Format

Ethereum: ERC-6093 custom errors standard

Monad: Same error format, works identically

Design implication: Same error handling code works

## Key Takeaways

- ERC-6093 = human-readable token errors
- Always decode errors, never show raw hex
- Show what user has vs what they need
- Offer clear recovery actions
- Common errors: InsufficientBalance, InsufficientAllowance

## Technical Notes

ERC-6093 defines custom errors: ERC20InsufficientBalance(sender, balance, needed), ERC20InsufficientAllowance(spender, allowance, needed), ERC721InsufficientApproval(operator, tokenId), etc. Decode using error selector (first 4 bytes) and ABI decode parameters. OpenZeppelin contracts v5+ use these errors.

## Official specification (reference only)

https://eips.ethereum.org/EIPS/eip-6093