This skill should be used when the user asks to "deploy an ERC20 token", "create a token", "implement ERC20", "add permit to token", "mint/burn functionality", "ERC4626 vault", "tokenized vault", "ERC721 NFT", or needs guidance on token standards implementation with Crane's Diamond Factory Packages.
Crane provides pre-built Diamond Factory Packages (DFPkg) for deploying ERC20, ERC20Permit, and ERC4626 tokens as Diamond proxies.
| Need | Package | Features |
|---|---|---|
| Basic ERC20 | ERC20DFPkg | Transfer, approve, metadata |
| ERC20 + Permit | ERC20PermitDFPkg | + EIP-2612 gasless approvals |
| Full-featured token | ERC20PermitMintBurnLockedOwnableDFPkg | + Mint/burn with owner control |
import {ERC20PermitDFPkg, IERC20PermitDFPkg} from "@crane/contracts/tokens/ERC20/ERC20PermitDFPkg.sol";
import {IERC20} from "@crane/contracts/interfaces/IERC20.sol";
// 1. Deploy facets (typically done once via FactoryService)
IFacet erc20Facet = factory.deployFacet(type(ERC20Facet).creationCode, salt);
IFacet erc5267Facet = factory.deployFacet(type(ERC5267Facet).creationCode, salt);
IFacet erc2612Facet = factory.deployFacet(type(ERC2612Facet).creationCode, salt);
// 2. Deploy package with facet references
ERC20PermitDFPkg pkg = new ERC20PermitDFPkg(IERC20PermitDFPkg.PkgInit({
erc20Facet: erc20Facet,
erc5267Facet: erc5267Facet,
erc2612Facet: erc2612Facet
}));
// 3. Deploy token instance via Diamond factory
IERC20 token = IERC20(diamondFactory.deploy(
pkg,
abi.encode(IERC20PermitDFPkg.PkgArgs({
name: "My Token",
symbol: "MTK",
decimals: 18,
totalSupply: 1_000_000e18,
recipient: msg.sender,
optionalSalt: bytes32(0)
}))
));
Basic ERC20 token with metadata.
PkgInit (constructor):
struct PkgInit {
IFacet erc20Facet;
}
PkgArgs (deployment):
struct PkgArgs {
string name;
string symbol;
uint8 decimals; // Defaults to 18 if 0
uint256 totalSupply; // Initial mint amount
address recipient; // Required if totalSupply > 0
bytes32 optionalSalt;
}
Interfaces: IERC20, IERC20Metadata
ERC20 with EIP-2612 permit (gasless approvals).
PkgInit:
struct PkgInit {
IFacet erc20Facet;
IFacet erc5267Facet; // EIP-5267 domain separator
IFacet erc2612Facet; // EIP-2612 permit
}
PkgArgs: Same as ERC20DFPkg
Interfaces: IERC20, IERC20Metadata, IERC20Permit, IERC5267
Full-featured token with owner-controlled mint/burn and time-locked ownership transfer.
PkgInit:
struct PkgInit {
IFacet erc20Facet;
IFacet erc5267Facet;
IFacet erc2612Facet;
IFacet erc20MintBurnOwnableFacet;
IDiamondPackageCallBackFactory diamondFactory;
}
PkgArgs:
struct PkgArgs {
string name;
string symbol;
uint8 decimals;
address owner; // Initial owner (mint/burn access)
bytes32 optionalSalt;
}
Interfaces: IERC20, IERC20Metadata, IERC20Permit, IERC5267, IERC20MintBurn
Convenience deploy function:
function deployToken(
string memory name,
string memory symbol,
uint8 decimals,
address owner,
bytes32 optionalSalt
) external returns (address tokenAddress);
| File | Purpose |
|---|---|
ERC20Repo.sol | Diamond storage for balances, allowances, metadata |
ERC20Target.sol | Business logic (transfer, approve, etc.) |
ERC20Facet.sol | Diamond facet exposing IERC20 + IFacet |
ERC20PermitTarget.sol | Permit extension logic |
ERC20PermitFacet.sol | Diamond facet for permit |
ERC20MintBurnOwnableFacet.sol | Mint/burn with onlyOwner modifier |
Tokens use standard Crane Repo pattern:
library ERC20Repo {
bytes32 internal constant STORAGE_SLOT = keccak256("eip.erc.20");
struct Storage {
string name;
string symbol;
uint8 decimals;
uint256 totalSupply;
mapping(address => uint256) balanceOf;
mapping(address => mapping(address => uint256)) allowance;
}
function _initialize(string memory name_, string memory symbol_, uint8 decimals_) internal;
function _mint(address to_, uint256 amount_) internal;
function _burn(address from_, uint256 amount_) internal;
function _transfer(address from_, address to_, uint256 amount_) internal;
}
Use the provided TestBase contracts:
import {TestBase_ERC20} from "@crane/contracts/tokens/ERC20/TestBase_ERC20.sol";
import {TestBase_ERC20Permit} from "@crane/contracts/tokens/ERC20/TestBase_ERC20Permit.sol";
contract MyToken_Test is TestBase_ERC20Permit {
function _deployToken() internal override returns (IERC20Permit) {
// Deploy your token instance
}
}
For detailed implementation patterns and examples:
references/token-packages.md - Complete package comparison and deployment patterns