Trait Hook 

pub trait Hook: Send + Sync {
    // Provided methods
    fn on_build_agent(&self, config: AgentConfig) -> AgentConfig { ... }
    fn on_event(&self, _agent: &str, _event: &AgentEvent) { ... }
    fn on_register_tools(
        &self,
        _tools: &mut ToolRegistry,
    ) -> impl Future<Output = ()> + Send { ... }
    fn on_compact(&self, _prompt: &mut String) { ... }
}

Lifecycle backend for agent building, event observation, and tool registration.

Default implementations are no-ops so implementors only override what they need.

Provided Methods

fn on_build_agent(&self, config: AgentConfig) -> AgentConfig

Called by Runtime::add_agent() before building the Agent.

Enriches the agent config: appends skill instructions, injects memory into the system prompt, etc. The returned config is passed to AgentBuilder.

Default: returns config unchanged.

fn on_event(&self, _agent: &str, _event: &AgentEvent)

Called by Runtime after each agent step during execution.

Receives every AgentEvent produced during send_to and stream_to. Use for logging, metrics, persistence, or forwarding.

Default: no-op.

fn on_register_tools( &self, _tools: &mut ToolRegistry, ) -> impl Future<Output = ()> + Send

Called by Runtime::new() to register tool schemas into the registry.

Implementations call tools.insert(tool) with schema-only Tool values. No handlers or closures are stored — dispatch is handled by the daemon.

Default: no-op async.

fn on_compact(&self, _prompt: &mut String)

Called during context compaction to enrich the compaction prompt.

Hooks append memory context (profile facts, recent entries) to the prompt before the LLM summarizes the conversation. The runtime passes the base prompt from compact.md; hooks mutate it in place.

Default: no-op.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl Hook for ()

Implementors