mcp-kit-macros

Procedural macros for the mcp-kit crate.

This crate provides attribute macros that simplify building MCP (Model Context Protocol) servers by automatically generating boilerplate code and JSON schemas.

Macros

#[tool]

Generate tools from async functions with automatic schema generation:

use mcp_kit::prelude::*;

#[tool(description = "Add two numbers")]
async fn add(a: f64, b: f64) -> String {
    format!("{}", a + b)
}

// Use the generated function
McpServer::builder()
    .tool_def(add_tool_def())
    .build()

#[resource]

Generate resource handlers for static or template URIs:

use mcp_kit::{resource, ReadResourceRequest, McpResult, ReadResourceResult};

#[resource(uri = "config://app", name = "App Config")]
async fn config(_req: ReadResourceRequest) -> McpResult<ReadResourceResult> {
    Ok(ReadResourceResult::text("config://app", "{}"))
}

// Template resource with {variables}
#[resource(uri = "file://{path}", name = "File System")]
async fn read_file(req: ReadResourceRequest) -> McpResult<ReadResourceResult> {
    // Implementation
}

#[prompt]

Generate prompt handlers with optional arguments:

use mcp_kit::{prompt, GetPromptRequest, McpResult, GetPromptResult, PromptMessage};

#[prompt(
    name = "greeting",
    description = "A friendly greeting",
    arguments = ["name:optional"]
)]
async fn hello(req: GetPromptRequest) -> McpResult<GetPromptResult> {
    let name = req.arguments.get("name").cloned().unwrap_or("there".into());
    Ok(GetPromptResult::new(vec![
        PromptMessage::user_text(format!("Hello, {}!", name))
    ]))
}

Usage

Add to your Cargo.toml:

[dependencies]
mcp-kit = "0.1"

The macros are automatically re-exported by mcp-kit, so you don't need to add this crate as a direct dependency.

Documentation

See the main mcp-kit documentation for complete usage guides and examples.

License

MIT