mcpkit-macros

Procedural macros for the Model Context Protocol (MCP) SDK.

This crate provides the unified #[mcp_server] macro that simplifies MCP server development by eliminating boilerplate.

Overview

The macro system provides:

Usage

use mcpkit::prelude::*;

struct Calculator;

#[mcp_server(name = "calculator", version = "1.0.0")]
impl Calculator {
    /// Add two numbers together
    #[tool(description = "Add two numbers")]
    async fn add(&self, a: f64, b: f64) -> ToolOutput {
        ToolOutput::text((a + b).to_string())
    }

    /// Multiply two numbers
    #[tool(description = "Multiply two numbers")]
    async fn multiply(&self, a: f64, b: f64) -> ToolOutput {
        ToolOutput::text((a * b).to_string())
    }
}

#[tokio::main]
async fn main() -> Result<(), McpError> {
    Calculator.serve_stdio().await
}

Attributes

#[mcp_server]

#[tool]

Generated Code

The #[mcp_server] macro generates:

1. impl ServerHandler with server_info() and capabilities()
2. impl ToolHandler with list_tools() and call_tool() (if any #[tool] methods)
3. impl ResourceHandler (if any #[resource] methods)
4. impl PromptHandler (if any #[prompt] methods)
5. A serve_stdio() convenience method

Code Reduction

This single macro replaces multiple manual implementations, significantly reducing boilerplate compared to implementing handler traits directly.

Part of mcpkit

This crate is part of the mcpkit SDK. For most use cases, depend on mcpkit directly rather than this crate.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.