Struct HookStack 

pub struct HookStack { /* private fields */ }

Ordered composable hook stack.

Model selections chain in registration order: each hook sees the candidate selected by earlier hooks, the last selection wins, and a stop is terminal. Nested stacks preserve the same composition semantics.

Implementations

impl HookStack

pub fn new() -> Self

Creates an empty hook stack.

pub fn with<H: AgentHook + 'static>(hook: H) -> Self

Creates a hook stack containing hook.

pub fn push<H: AgentHook + 'static>(&mut self, hook: H)

Appends a hook to the end of the stack’s registration order.

pub fn is_empty(&self) -> bool

Returns true when the stack contains no hooks.

pub fn len(&self) -> usize

Returns the number of hooks in the stack.

Trait Implementations

impl AgentHook for HookStack

fn on_model_select( &self, ctx: &HookContext, event: ModelSelection<'_>, ) -> ModelSelectionAction

Selects the model for the pending model-call boundary.

async fn on_completion_call( &self, ctx: &HookContext, event: CompletionCall<'_>, ) -> CompletionCallAction

Runs before a completion request is sent.

async fn on_completion_response( &self, ctx: &HookContext, event: CompletionResponse<'_>, ) -> ObservationAction

Observes a completed model response.

async fn on_model_turn_finished( &self, ctx: &HookContext, event: ModelTurnFinished<'_>, ) -> ModelTurnAction

Observes or rejects the content produced at the end of a model turn.

async fn on_text_delta( &self, ctx: &HookContext, event: TextDelta<'_>, ) -> ObservationAction

Observes a text delta from a streaming response.

async fn on_reasoning_delta( &self, ctx: &HookContext, event: ReasoningDelta<'_>, ) -> ObservationAction

Observes a reasoning delta from a streaming response.

async fn on_tool_call_delta( &self, ctx: &HookContext, event: ToolCallDelta<'_>, ) -> ObservationAction

Observes an argument delta for a streaming tool call.

async fn on_stream_response_finish( &self, ctx: &HookContext, event: StreamResponseFinish<'_>, ) -> ObservationAction

Observes a completed streaming response in canonical Rig form.

async fn on_invalid_tool_call( &self, ctx: &HookContext, event: &InvalidToolCallContext, ) -> Option<InvalidToolCallAction>

Resolves a model-emitted tool call that cannot be dispatched as written.

async fn on_tool_call( &self, ctx: &HookContext, event: ToolCall<'_>, ) -> ToolCallAction

Runs before a valid tool call is executed.

async fn on_tool_result( &self, ctx: &HookContext, event: ToolResultEvent<'_>, ) -> ToolResultAction

Runs after a tool call resolves and before its presentation is sent to the model.

fn observes(&self, kind: StepEventKind) -> bool

Observation interest hint, primarily for high-frequency deltas.

impl Clone for HookStack

fn clone(&self) -> HookStack

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HookStack

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

Formats the value using the given formatter.

impl Default for HookStack

fn default() -> HookStack

Returns the “default value” for a type.