Struct TurnEngine 

pub struct TurnEngine;

The single interpreter of Agentyk turn semantics.

Implementations

impl TurnEngine

pub async fn start( &self, host: &TurnHost<'_>, input: Message, ) -> PreparedTurnStart

Open a turn and apply user_prompt_submit hooks before its input is persisted.

Durable and immediate hosts both call this method, so prompt mutation and rejection cannot drift between execution strategies.

pub async fn finish( &self, host: &TurnHost<'_>, turn_id: TurnId, data: Value, ) -> Vec<EventData>

Apply advisory turn_end hooks to a host-provided terminal summary.

data uses the public hook wire shape (success plus result/error details). The engine owns dispatch and error policy; a durable host owns when its terminal operation has been committed and therefore when to call this method. Like tool execution, a hook may run more than once if the durable host crashes before committing its effects.

pub async fn assemble(&self, host: &TurnHost<'_>) -> Result<AssembledTurn>

Resolve the agent’s capabilities into the environment used by steps.

pub async fn prepare( &self, host: &TurnHost<'_>, assembled: &AssembledTurn, state: &mut TurnState, ) -> Result<PreparedStep>

Prepare exactly one operation from the current state.

A durable host persists the returned events before scheduling the operation. The in-process host records them and executes immediately.

pub async fn guard( &self, host: &TurnHost<'_>, state: &mut TurnState, ) -> Option<PreparedStep>

Apply cancellation and budget policy before one external action.

Hosts that execute a prepared tool batch one call at a time use this between calls so policy remains responsive inside the batch.

pub fn complete_model( &self, state: &mut TurnState, response: &ChatResponse, ) -> Vec<EventData>

Apply a successful model operation and return its durable events.

pub fn fail_model(&self, state: &mut TurnState, error: &Error) -> Vec<EventData>

Apply a failed model operation and return its durable event.

pub async fn complete_tool( &self, host: &TurnHost<'_>, assembled: &AssembledTurn, state: &mut TurnState, call: &ToolCall, output: ToolOutput, denied: bool, ) -> Vec<EventData>

Apply one tool result, including post-tool middleware when the tool actually ran, and return its durable completion event.

Trait Implementations

impl Clone for TurnEngine

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TurnEngine

impl Debug for TurnEngine

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

Formats the value using the given formatter.

impl Default for TurnEngine

fn default() -> Self

Returns the “default value” for a type.