Enum DualEraServerToClient 

pub enum DualEraServerToClient {
    Legacy2024 {
        sender: RequestSender,
    },
    Modern2026 {
        exchanges: Arc<MrtrExchangeRegistry>,
    },
}

Era-selected server-to-client input boundary.

The exact MCP 2024-11-05 variant owns the transport sender and may issue only sampling/createMessage, elicitation/create, and roots/list reverse JSON-RPC requests. The MCP 2026-07-28 variant deliberately does not retain that sender: it can only issue and consume the bounded MrtrExchangeRegistry input_required retry flow.

Variants

Legacy2024

Exact MCP 2024-11-05 reverse JSON-RPC support.

Fields

sender: RequestSender

The connection’s reverse-request sender.

Modern2026

MCP 2026-07-28 embedded input/retry support.

Fields

exchanges: Arc<MrtrExchangeRegistry>

The server-local registry for bounded input exchanges.

Implementations

impl DualEraServerToClient

pub fn new( era: ProtocolEra, legacy_sender: RequestSender, exchanges: Arc<MrtrExchangeRegistry>, ) -> Self

Selects the sole server-to-client mechanism for one negotiated era.

The legacy sender is intentionally consumed and discarded for MCP 2026-07-28. That makes reverse JSON-RPC unavailable in the final-era variant even if the connection also has a transport send callback.

pub const fn era(&self) -> ProtocolEra

Returns the exact negotiated era selected by this boundary.

pub async fn sampling_create_message( &self, cx: &Cx, owner_cancellation: McpRequestCancellation, input_key: impl Into<String>, params: DualEraSamplingParams, ) -> McpResult<DualEraServerToClientResult<CreateMessageResult>>

Requests a client sampling completion.

In the legacy era this sends sampling/createMessage directly. In the final era it returns an input_required result whose input descriptor has that exact method and is owned by owner_cancellation.

pub async fn elicitation_create( &self, cx: &Cx, owner_cancellation: McpRequestCancellation, input_key: impl Into<String>, params: DualEraElicitationParams, ) -> McpResult<DualEraServerToClientResult<ElicitResult>>

Requests client elicitation input.

In the legacy era this sends elicitation/create directly. In the final era it returns an input_required result whose input descriptor has that exact method and is owned by owner_cancellation.

pub async fn roots_list( &self, cx: &Cx, owner_cancellation: McpRequestCancellation, input_key: impl Into<String>, ) -> McpResult<DualEraServerToClientResult<ListRootsResult>>

Requests the client’s filesystem roots.

In the legacy era this sends roots/list directly. In the final era it returns an input_required result whose input descriptor has that exact method and is owned by owner_cancellation.

pub fn accept_input_retry( &self, cx: &Cx, request_state: &str, input_responses: MrtrInputResponses, ) -> McpResult<MrtrRetry>

Consumes one final-era inputResponses retry.

This accepts retries only for MCP 2026-07-28. The caller supplies the active Cx for cancellation/budget authority; the registry retains the request-local cancellation owner that was bound when it issued the corresponding input_required result.

Trait Implementations

impl Clone for DualEraServerToClient

fn clone(&self) -> DualEraServerToClient

Returns a duplicate of the value.

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

Performs copy-assignment from source.