Trait Channel 

pub trait Channel: Send {
    // Required methods
    fn recv(
        &mut self,
    ) -> impl Future<Output = Result<Option<ChannelMessage>, ChannelError>> + Send;
    fn send(
        &mut self,
        text: &str,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send;
    fn send_chunk(
        &mut self,
        chunk: &str,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send;
    fn flush_chunks(
        &mut self,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send;

    // Provided methods
    fn try_recv(&mut self) -> Option<ChannelMessage> { ... }
    fn supports_exit(&self) -> bool { ... }
    fn send_typing(
        &mut self,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_status(
        &mut self,
        _text: &str,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_thinking_chunk(
        &mut self,
        _chunk: &str,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_queue_count(
        &mut self,
        _count: usize,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_usage(
        &mut self,
        _input_tokens: u64,
        _output_tokens: u64,
        _context_window: u64,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_diff(
        &mut self,
        _diff: DiffData,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_tool_start(
        &mut self,
        _event: ToolStartEvent,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn send_tool_output(
        &mut self,
        event: ToolOutputEvent,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
    fn confirm(
        &mut self,
        _prompt: &str,
    ) -> impl Future<Output = Result<bool, ChannelError>> + Send { ... }
    fn elicit(
        &mut self,
        _request: ElicitationRequest,
    ) -> impl Future<Output = Result<ElicitationResponse, ChannelError>> + Send { ... }
    fn send_stop_hint(
        &mut self,
        _hint: StopHint,
    ) -> impl Future<Output = Result<(), ChannelError>> + Send { ... }
}

Bidirectional communication channel for the agent.

Required Methods

fn recv( &mut self, ) -> impl Future<Output = Result<Option<ChannelMessage>, ChannelError>> + Send

Receive the next message. Returns None on EOF or shutdown.

Errors

Returns an error if the underlying I/O fails.

fn send( &mut self, text: &str, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a text response.

Errors

Returns an error if the underlying I/O fails.

fn send_chunk( &mut self, chunk: &str, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a partial chunk of streaming response.

Errors

Returns an error if the underlying I/O fails.

fn flush_chunks( &mut self, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Flush any buffered chunks.

Errors

Returns an error if the underlying I/O fails.

Provided Methods

fn try_recv(&mut self) -> Option<ChannelMessage>

Non-blocking receive. Returns None if no message is immediately available.

fn supports_exit(&self) -> bool

Whether /exit and /quit commands should terminate the agent loop.

Returns false for persistent server-side channels (e.g. Telegram) where breaking the loop would not meaningfully exit from the user’s perspective.

fn send_typing( &mut self, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a typing indicator. No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_status( &mut self, _text: &str, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a status label (shown as spinner text in TUI). No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_thinking_chunk( &mut self, _chunk: &str, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a thinking/reasoning token chunk. No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_queue_count( &mut self, _count: usize, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Notify channel of queued message count. No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_usage( &mut self, _input_tokens: u64, _output_tokens: u64, _context_window: u64, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send token usage after an LLM call. No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_diff( &mut self, _diff: DiffData, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send diff data for a tool result. No-op by default (TUI overrides).

Errors

Returns an error if the underlying I/O fails.

fn send_tool_start( &mut self, _event: ToolStartEvent, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Announce that a tool call is starting.

Emitted before execution begins so the transport layer can send an InProgress status to the peer before the result arrives. No-op by default.

Errors

Returns an error if the underlying I/O fails.

fn send_tool_output( &mut self, event: ToolOutputEvent, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Send a complete tool output with optional diff and filter stats atomically.

display is the formatted tool output. The default implementation forwards to Channel::send. Structured channels (e.g. LoopbackChannel) override this to emit a typed event so consumers can access tool_name and display as separate fields.

Errors

Returns an error if the underlying I/O fails.

fn confirm( &mut self, _prompt: &str, ) -> impl Future<Output = Result<bool, ChannelError>> + Send

Request user confirmation for a destructive action. Returns true if confirmed. Default: auto-confirm (for headless/test scenarios).

Errors

Returns an error if the underlying I/O fails.

fn elicit( &mut self, _request: ElicitationRequest, ) -> impl Future<Output = Result<ElicitationResponse, ChannelError>> + Send

Request structured input from the user for an MCP elicitation.

Always displays request.server_name to prevent phishing by malicious servers. Default: auto-decline (for headless/daemon/non-interactive scenarios).

Errors

Returns an error if the underlying I/O fails.

fn send_stop_hint( &mut self, _hint: StopHint, ) -> impl Future<Output = Result<(), ChannelError>> + Send

Signal the non-default stop reason to the consumer before flushing.

Called by the agent loop immediately before flush_chunks() when a truncation or turn-limit condition is detected. No-op by default.

Errors

Returns an error if the underlying I/O fails.

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.

Implementors

impl Channel for LoopbackChannel