Trait PromptHook 

pub trait PromptHook<M>:
    Clone
    + WasmCompatSend
    + WasmCompatSync
where
    M: CompletionModel,
{
    // Provided methods
    fn on_completion_call(
        &self,
        _prompt: &Message,
        _history: &[Message],
    ) -> impl Future<Output = HookAction> + WasmCompatSend { ... }
    fn on_completion_response(
        &self,
        _prompt: &Message,
        _response: &CompletionResponse<M::Response>,
    ) -> impl Future<Output = HookAction> + WasmCompatSend { ... }
    fn on_invalid_tool_call(
        &self,
        _context: &InvalidToolCallContext,
    ) -> impl Future<Output = InvalidToolCallHookAction> + WasmCompatSend { ... }
    fn on_tool_call(
        &self,
        _tool_name: &str,
        _tool_call_id: Option<String>,
        _internal_call_id: &str,
        _args: &str,
    ) -> impl Future<Output = ToolCallHookAction> + WasmCompatSend { ... }
    fn on_tool_result(
        &self,
        _tool_name: &str,
        _tool_call_id: Option<String>,
        _internal_call_id: &str,
        _args: &str,
        _result: &str,
    ) -> impl Future<Output = HookAction> + WasmCompatSend { ... }
    fn on_text_delta(
        &self,
        _text_delta: &str,
        _aggregated_text: &str,
    ) -> impl Future<Output = HookAction> + Send { ... }
    fn on_tool_call_delta(
        &self,
        _tool_call_id: &str,
        _internal_call_id: &str,
        _tool_name: Option<&str>,
        _tool_call_delta: &str,
    ) -> impl Future<Output = HookAction> + Send { ... }
    fn on_stream_completion_response_finish(
        &self,
        _prompt: &Message,
        _response: &<M as CompletionModel>::StreamingResponse,
    ) -> impl Future<Output = HookAction> + Send { ... }
}

Trait for per-request hooks to observe tool call events.

Provided Methods

fn on_completion_call( &self, _prompt: &Message, _history: &[Message], ) -> impl Future<Output = HookAction> + WasmCompatSend

Called before the prompt is sent to the model

fn on_completion_response( &self, _prompt: &Message, _response: &CompletionResponse<M::Response>, ) -> impl Future<Output = HookAction> + WasmCompatSend

Called after the prompt is sent to the model and a response is received.

fn on_invalid_tool_call( &self, _context: &InvalidToolCallContext, ) -> impl Future<Output = InvalidToolCallHookAction> + WasmCompatSend

Called when a model-emitted tool call is unknown or disallowed by the current request’s tool choice.

The default behavior remains fail-fast. Override this method to opt into retry, repair, or skip recovery for invalid tool calls.

fn on_tool_call( &self, _tool_name: &str, _tool_call_id: Option<String>, _internal_call_id: &str, _args: &str, ) -> impl Future<Output = ToolCallHookAction> + WasmCompatSend

Called before a tool is invoked.

Returns

• ToolCallHookAction::Continue - Allow tool execution to proceed
• ToolCallHookAction::Skip { reason } - Reject tool execution; reason will be returned to the LLM as the tool result

fn on_tool_result( &self, _tool_name: &str, _tool_call_id: Option<String>, _internal_call_id: &str, _args: &str, _result: &str, ) -> impl Future<Output = HookAction> + WasmCompatSend

Called after a tool is invoked (and a result has been returned).

fn on_text_delta( &self, _text_delta: &str, _aggregated_text: &str, ) -> impl Future<Output = HookAction> + Send

Called when receiving a text delta (streaming responses only)

fn on_tool_call_delta( &self, _tool_call_id: &str, _internal_call_id: &str, _tool_name: Option<&str>, _tool_call_delta: &str, ) -> impl Future<Output = HookAction> + Send

Called when receiving a tool call delta (streaming_responses_only). tool_name is Some on the first delta for a tool call, None on subsequent deltas.

fn on_stream_completion_response_finish( &self, _prompt: &Message, _response: &<M as CompletionModel>::StreamingResponse, ) -> impl Future<Output = HookAction> + Send

Called after the model provider has finished streaming a text response from their completion API to the client.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<M> PromptHook<M> for ()

where M: CompletionModel,

Implementors