Module hooks 

Lifecycle hook callbacks (pre/post tool use, prompt submission, session start/end). Lifecycle hook callbacks invoked at key session points.

Hooks let you intercept and modify CLI behavior — approve or deny tool use, rewrite user prompts, inject context at session start, and handle errors. Implement SessionHooks and pass it to Client::create_session.

Structs

ErrorOccurredInput

Input for the errorOccurred hook.

ErrorOccurredOutput

Output for the errorOccurred hook.

HookContext

Context provided to every hook invocation.

PostToolUseInput

Input for the postToolUse hook — received after a tool executes.

PostToolUseOutput

Output for the postToolUse hook.

PreToolUseInput

Input for the preToolUse hook — received before a tool executes.

PreToolUseOutput

Output for the preToolUse hook.

SessionEndInput

Input for the sessionEnd hook.

SessionEndOutput

Output for the sessionEnd hook.

SessionStartInput

Input for the sessionStart hook.

SessionStartOutput

Output for the sessionStart hook.

UserPromptSubmittedInput

Input for the userPromptSubmitted hook — received when the user sends a message.

UserPromptSubmittedOutput

Output for the userPromptSubmitted hook.

Enums

HookEvent

Events dispatched to SessionHooks::on_hook at CLI lifecycle points.

HookOutput

Response from SessionHooks::on_hook back to the SDK.

Traits

SessionHooks

Callback trait for session hooks — invoked by the CLI at key lifecycle points (tool use, prompt submission, session start/end, errors).