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add_hook

Function
This function is defined in the registry module.
Register a hook callback. Simplified API. Accepts both string event names and HookEvent enums: add_hook(‘before_tool’, my_callback) # String add_hook(HookEvent.BEFORE_TOOL, my_callback) # Enum Can also be used as a decorator: @add_hook(‘before_tool’) def my_hook(data): return HookResult.allow()

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Signature

def add_hook(event: Union[str, HookEvent], callback: Optional[Callable[[HookInput], HookResult]], priority: int, matcher: Optional[str]) -> Union[str, Callable]

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Parameters

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event
Union
required
Hook event name (‘before_tool’, ‘after_llm’, etc.) or HookEvent enum
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callback
Optional
Function to call when hook fires (optional when using as decorator)
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priority
int
default:"10"
Execution order (lower = earlier). Default 10. (Reserved for future use)
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matcher
Optional
Optional regex pattern to match specific targets (e.g., tool names)

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Returns

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Returns
Union[str, Callable]
Hook ID for later removal, or a decorator function if callback is None

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Exceptions

If event string is not a valid HookEvent