Enum Event 

#[non_exhaustive]
pub enum Event {
    PreToolUse,
    PostToolUse,
    Custom(String),
}

Lifecycle event to attach to. Each integration maps this to its harness’s own event name (e.g., PreToolUse on Claude Code, BeforeTool on Gemini, tool.execute.before on OpenCode).

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

PreToolUse

Fire before a tool call is executed (the most common case; lets the hook modify or block the call).

PostToolUse

Fire after a tool call completes.

Custom(String)

Pass through a custom event name verbatim.

Trait Implementations

impl Clone for Event

fn clone(&self) -> Event

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Event

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.