rust-docs-mcp CLAUDE.md

When testing the rust-docs MCP server, call the tools from the rust-docs-testing MCP.

MCP Rust SDK Macros

Core Macros for Tool Declaration

1. #[tool_router] - Applied to impl blocks to generate tool routing

   • Automatically creates a tool_router() method returning ToolRouter<Self>
   • Must be used on the service struct's implementation

2. #[tool] - Marks individual methods as MCP tools

   • Required parameter: description = "tool description"
   • Methods must be pub async fn
   • Can return any serializable type

3. #[tool_handler] - Applied to ServerHandler trait implementation

   • Required for the service to work with serve_server()
   • Must implement get_info() returning ServerInfo

Parameter Handling

1. Parameters<T> Wrapper - Required for ALL tool parameters

   pub async fn my_tool(&self, Parameters(params): Parameters<MyParams>) -> String
   

   • Type T must implement JsonSchema, Deserialize, Serialize
   • Always destructure with Parameters(params) pattern

Required Imports

use rmcp::{
    ServerHandler,
    handler::server::{router::tool::ToolRouter, tool::Parameters},
    model::{ServerCapabilities, ServerInfo},
    tool, tool_handler, tool_router,
};

Note: Parameters must be imported from handler::server::tool::Parameters, not directly from rmcp.

Complete Service Pattern

use rmcp::{
    ServerHandler,
    handler::server::{router::tool::ToolRouter, tool::Parameters},
    model::{ServerCapabilities, ServerInfo},
    tool, tool_handler, tool_router,
};
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
pub struct MyParams {
    #[schemars(description = "Parameter description")]
    pub param_name: String,
}

#[derive(Debug, Clone)]
pub struct MyService {
    tool_router: ToolRouter<Self>,
    // other fields
}

#[tool_router]
impl MyService {
    pub fn new() -> Self {
        Self {
            tool_router: Self::tool_router(), // Generated by macro
            // other fields
        }
    }
    
    #[tool(description = "Does something useful")]
    pub async fn my_tool(&self, Parameters(params): Parameters<MyParams>) -> String {
        // Implementation using params.param_name
        format!("Processed: {}", params.param_name)
    }
}

#[tool_handler]
impl ServerHandler for MyService {
    fn get_info(&self) -> ServerInfo {
        ServerInfo {
            capabilities: ServerCapabilities::builder().enable_tools().build(),
            // other config
        }
    }
}