ERC-20 Metadata Facet

@perfect-abstractions/compose/token/ERC20/Metadata/ERC20MetadataFacet.solCopy

Read-only access to the token name, symbol, and decimals

Key Features

• Exposes the three ERC-20 metadata view functions: name(), symbol() and decimals().
• Uses ERC20MetadataStorage at erc8042:erc20.metadata, a different slot from balances and allowances.
• Read-only facet. Values are written by ERC20MetadataMod.

Storage​

State Variables​

ERC20MetadataStorage​

/** @custom:storage-location erc8042:erc20.metadata */
struct ERC20MetadataStorage {
  string name;
  string symbol;
  uint8 decimals;
}

Functions​

name​

Returns the descriptive name of the token, for example "My Token".

function name() external view returns (string memory);

Returns:

symbol​

Returns the short ticker of the token, for example "MTK".

function symbol() external view returns (string memory);

Returns:

decimals​

Returns how many decimal places wallets and interfaces should use when displaying balances.

function decimals() external view returns (uint8);

Returns:

Best Practices​

• Add this facet together with ERC20DataFacet. Wallets and explorers expect both the balance functions and the metadata functions.
• Set all three values once during deployment with ERC20MetadataMod.setMetadata. Reading this facet before that happens returns empty strings and 0.
• Choose decimals before launch and leave it alone. Changing it later reinterprets every balance already held.

Security Considerations​

This facet only reads storage, so it cannot corrupt token state on its own. Two consequences of the shared slot are worth knowing:

• Renaming the token invalidates outstanding permit signatures. ERC20PermitFacet hashes the stored name into its EIP-712 domain, both in DOMAIN_SEPARATOR() and again inside permit(). If name changes, previously signed permits no longer verify and integrators that cached the old domain separator will produce failing signatures.
• decimals is display only. Nothing in Compose does arithmetic with it. Balances, allowances, and the total supply are raw integers, so treat this value as a hint for user interfaces rather than a unit of account.

Last updated:September 16, 2026

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