Interface Lint

Format Solidity interface files following EigenLayer's established conventions for organization, documentation, and error code generation.

Interface Structure

Every interface file should contain four interface contracts in this order:

1. I{ContractName}Errors - All custom errors
2. I{ContractName}Types - All structs and enums
3. I{ContractName}Events - All events (inherits Types for struct access)
4. I{ContractName} - Main interface (inherits Errors and Events)

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.27;

// Imports

interface I{ContractName}Errors {
    // All errors with error codes
}

interface I{ContractName}Types {
    // All structs and enums
}

interface I{ContractName}Events is I{ContractName}Types {
    // All events
}

interface I{ContractName} is I{ContractName}Errors, I{ContractName}Events {
    // All function declarations
}

Error Documentation

Each error MUST include:

1. @notice describing when the error is thrown
2. @dev Error code: 0x... with the 4-byte selector from cast sig

Generating Error Codes

Use cast sig to generate the error code:

cast sig "InvalidOperatorSet()"
# Output: 0x7ec5c154

Error Format

interface IContractNameErrors {
    /// @notice Thrown when the operator set is not valid
    /// @dev Error code: 0x7ec5c154
    error InvalidOperatorSet();

    /// @notice Thrown when the chainId is invalid
    /// @dev Error code: 0x7a47c9a2
    error InvalidChainId();

    /// @notice Thrown when the key type is not set for the operatorSet
    /// @dev Error code: 0xe57cacbd
    /// @dev Additional context about why this is required
    error KeyTypeNotSet();
}

Types Documentation

Each struct/enum MUST include:

1. @notice with a brief description
2. @param for each field in structs

interface IContractNameTypes {
    /// @notice A per-operatorSet configuration struct
    /// @param owner the permissioned owner of the OperatorSet
    /// @param maxStalenessPeriod the maximum staleness period in seconds
    struct OperatorSetConfig {
        address owner;
        uint32 maxStalenessPeriod;
    }

    /// @notice Represents the status of an operator's registration
    /// @param registered Whether the operator is currently registered
    /// @param slashableUntil Block until which the operator remains slashable
    struct RegistrationStatus {
        bool registered;
        uint32 slashableUntil;
    }
}

Event Documentation

Each event MUST include a singular @notice describing when the event is emitted:

interface IContractNameEvents is IContractNameTypes {
    /// @notice Emitted when a generation reservation is created
    event GenerationReservationCreated(OperatorSet operatorSet);

    /// @notice Emitted when an operator set config is set
    event OperatorSetConfigSet(OperatorSet operatorSet, OperatorSetConfig config);

    /// @notice Emitted when a chainID is added to the whitelist
    event ChainIDAddedToWhitelist(uint256 chainID, address operatorTableUpdater);
}

Function Documentation

Each function in the main interface MUST include:

1. @notice - What the function does
2. @param - Description for each parameter
3. @return - Description for each return value (for view functions)
4. @dev - Additional context (optional, but include caller requirements)
5. @dev Reverts for: - List ALL revert conditions
6. @dev Emits the following events: - List ALL events emitted

Function Documentation Format

interface IContractName is IContractNameErrors, IContractNameEvents {
    /// @notice Creates a generation reservation for cross-chain transport
    /// @param operatorSet the operatorSet to make a reservation for
    /// @param operatorTableCalculator the calculator contract address
    /// @param config the config containing owner and staleness period
    /// @dev msg.sender must be an authorized caller for operatorSet.avs
    /// @dev Reverts for:
    ///      - CurrentlyPaused: Generation reservations are paused
    ///      - InvalidPermissions: Caller is not authorized
    ///      - InvalidOperatorSet: The operatorSet does not exist
    ///      - GenerationReservationAlreadyExists: Reservation already exists
    ///      - InvalidStalenessPeriod: The maxStalenessPeriod is invalid
    /// @dev Emits the following events:
    ///      - GenerationReservationCreated: When the reservation is created
    ///      - OperatorTableCalculatorSet: When the calculator is set
    ///      - OperatorSetConfigSet: When the config is set
    function createGenerationReservation(
        OperatorSet calldata operatorSet,
        IOperatorTableCalculator operatorTableCalculator,
        OperatorSetConfig calldata config
    ) external;

    /// @notice Gets the operator set config
    /// @param operatorSet the operatorSet to query
    /// @return The OperatorSetConfig for the given operatorSet
    /// @dev You should check if an operatorSet has an active reservation first
    function getOperatorSetConfig(
        OperatorSet memory operatorSet
    ) external view returns (OperatorSetConfig memory);
}

Revert Conditions Format

List each revert condition with the error name and when it occurs:

/// @dev Reverts for:
///      - CurrentlyPaused: Generation reservations are paused
///      - InvalidPermissions: Caller is not an authorized caller for operatorSet.avs
///      - InvalidOperatorSet: The operatorSet does not exist in the AllocationManager
///      - GenerationReservationAlreadyExists: A generation reservation already exists

For Ownable errors, use the string format:

/// @dev Reverts for:
///      - "Ownable: caller is not the owner": Caller is not the owner

Events Emitted Format

List each event with a brief description of when it's emitted:

/// @dev Emits the following events:
///      - GenerationReservationCreated: When the reservation is successfully created
///      - OperatorTableCalculatorSet: When the calculator is set for the operatorSet
///      - OperatorSetConfigSet: When the config is set for the operatorSet

View Functions

View functions typically don't revert (except for input validation) and don't emit events. Document them simpler:

/// @notice Gets the active generation reservations
/// @return An array of operatorSets with active generationReservations
function getActiveGenerationReservations() external view returns (OperatorSet[] memory);

/// @notice Gets reservations by range for pagination
/// @param startIndex the start index of the range, inclusive
/// @param endIndex the end index of the range, exclusive
/// @return An array of operatorSets in the specified range
/// @dev Reverts for:
///      - InvalidRange: startIndex is greater than endIndex
///      - InvalidEndIndex: endIndex exceeds array length
function getActiveGenerationReservationsByRange(
    uint256 startIndex,
    uint256 endIndex
) external view returns (OperatorSet[] memory);

Complete Example

Reference: src/contracts/interfaces/ICrossChainRegistry.sol

This file demonstrates the full pattern with:

• Errors interface with cast sig error codes
• Types interface with documented structs
• Events interface inheriting Types
• Main interface with full function documentation

Checklist for Linting an Interface

1. ☐ Split into Errors, Types, Events, and main interface contracts
2. ☐ Errors have @notice and @dev Error code: 0x... (use cast sig)
3. ☐ Types have @notice and @param for each field
4. ☐ Events have singular @notice describing when emitted
5. ☐ Events interface inherits Types interface
6. ☐ Main interface inherits Errors and Events interfaces
7. ☐ Functions have @notice, @param, and @return (for views)
8. ☐ Functions list ALL revert conditions under @dev Reverts for:
9. ☐ Functions list ALL events under @dev Emits the following events:
10. ☐ View functions document reverts only when they can revert

Generating All Error Codes

To generate error codes for an entire interface:

# For each error in the interface, run:
cast sig "ErrorName()"
cast sig "ErrorName(uint256)"  # Include params if error has them

# Example output:
# 0x7ec5c154  # InvalidOperatorSet()
# 0x7a47c9a2  # InvalidChainId()

Common Error Patterns

Error	Typical Code	Usage
InvalidOperatorSet()	0x7ec5c154	OperatorSet doesn't exist
InvalidPermissions()	varies	Caller not authorized
InvalidCaller()	varies	Wrong msg.sender
ArrayLengthMismatch()	0xa24a13a6	Input arrays have different lengths