Module handler 

MCP Handler Trait and Core Types

This module defines the core McpHandler trait that servers must implement to provide MCP functionality. It also includes essential types for notifications, context management, and protocol data structures.

Overview

The McpHandler trait is the main integration point for the solidmcp library. You can either implement this trait directly for full control, or use the higher-level framework API in the framework module for a more ergonomic experience.

Example Implementation

use solidmcp::handler::{McpHandler, McpContext, ToolDefinition};
use anyhow::Result;
use async_trait::async_trait;
use serde_json::{json, Value};

struct MyHandler {
    // Your application state
}

#[async_trait]
impl McpHandler for MyHandler {
    async fn initialize(&self, params: Value, context: &McpContext) -> Result<Value> {
        Ok(json!({
            "protocolVersion": "2025-06-18",
            "capabilities": {
                "tools": {}
            },
            "serverInfo": {
                "name": "my-server",
                "version": "1.0.0"
            }
        }))
    }

    async fn list_tools(&self, context: &McpContext) -> Result<Vec<ToolDefinition>> {
        Ok(vec![
            ToolDefinition {
                name: "hello".to_string(),
                description: "Say hello".to_string(),
                input_schema: json!({
                    "type": "object",
                    "properties": {
                        "name": { "type": "string" }
                    },
                    "required": ["name"]
                }),
            }
        ])
    }

    async fn call_tool(&self, name: &str, arguments: Value, context: &McpContext) -> Result<Value> {
        match name {
            "hello" => {
                let name = arguments.get("name")
                    .and_then(|v| v.as_str())
                    .unwrap_or("World");
                Ok(json!({ "message": format!("Hello, {}!", name) }))
            }
            _ => Err(anyhow::anyhow!("Unknown tool: {}", name))
        }
    }
}

Structs

McpContext

Context provided to MCP handler methods.

PromptArgument

Prompt argument definition.

PromptContent

Prompt content for MCP prompts/get response.

PromptInfo

Prompt information for MCP prompts/list response.

PromptMessage

Prompt message.

ResourceContent

Resource content for MCP resources/read response.

ResourceInfo

Resource information for MCP resources/list response.

ToolDefinition

Tool definition for MCP tools/list response.

TypedToolDefinition

Typed tool definition helper that provides compile-time type safety.

Enums

LogLevel

Log levels for log message notifications.

McpNotification

Notification types that can be sent from server to client.

Traits

McpHandler

Core trait that users must implement to provide MCP functionality.