Module handlers 

Handler traits for bidirectional communication in MCP client

This module provides handler traits and registration mechanisms for processing server-initiated requests. The MCP protocol is bidirectional, meaning servers can also send requests to clients for various purposes like elicitation, progress reporting, logging, and resource updates.

Handler Types

• ElicitationHandler: Handle user input requests from servers
• ProgressHandler: Process progress notifications from long-running operations
• LogHandler: Route server log messages to client logging systems
• ResourceUpdateHandler: Handle notifications when resources change

Usage

use turbomcp_client::handlers::{ElicitationHandler, ElicitationRequest, ElicitationResponse, HandlerError};
use async_trait::async_trait;

// Implement elicitation handler
#[derive(Debug)]
struct MyElicitationHandler;

#[async_trait]
impl ElicitationHandler for MyElicitationHandler {
    async fn handle_elicitation(
        &self,
        request: ElicitationRequest,
    ) -> Result<ElicitationResponse, HandlerError> {
        // Present schema to user and collect input
        // Return user's response
        todo!("Implement user interaction")
    }
}

Structs

DeclineElicitationHandler

Default elicitation handler that declines all requests

ElicitationRequest

Request structure for elicitation operations

ElicitationResponse

Response structure for elicitation operations (MCP-compliant)

HandlerRegistry

Registry for managing client-side handlers

LogMessage

Log message from the server

LoggingProgressHandler

Default progress handler that logs progress to tracing

LoggingResourceUpdateHandler

Default resource update handler that logs changes

ProgressNotification

Progress notification from server operations

ResourceUpdateNotification

Resource update notification

TracingLogHandler

Default log handler that routes server logs to tracing

Enums

ElicitationAction

Elicitation response action indicating user’s choice

HandlerError

Errors that can occur during handler operations

ResourceChangeType

Types of resource changes

Traits

ElicitationHandler

Handler for server-initiated elicitation requests

LogHandler

Handler for server log messages

ProgressHandler

Handler for server progress notifications

ResourceUpdateHandler

Handler for resource update notifications

Type Aliases

HandlerResult