protomcp

Rust SDK for protomcp -- build MCP servers with tools, resources, and prompts in one file, one command.

Install

Add to your Cargo.toml:

[dependencies]
protomcp = "0.1"
tokio = { version = "1", features = ["full"] }

You also need the pmcp CLI:

brew install msilverblatt/tap/protomcp

Quick Start

use protomcp::{tool, ToolResult, ArgDef};

#[tokio::main]
async fn main() {
    tool("add")
        .description("Add two numbers")
        .arg(ArgDef::int("a"))
        .arg(ArgDef::int("b"))
        .handler(|_ctx, args| {
            let a = args["a"].as_i64().unwrap_or(0);
            let b = args["b"].as_i64().unwrap_or(0);
            ToolResult::new(format!("{}", a + b))
        })
        .register();
    protomcp::run().await;
}

pmcp dev src/main.rs

Tool Groups

Group related actions under a single tool with per-action schemas:

use protomcp::{tool_group, action, ToolResult, ArgDef};

tool_group("math")
    .description("Math operations")
    .action(action("add")
        .description("Add two numbers")
        .arg(ArgDef::int("a"))
        .arg(ArgDef::int("b"))
        .handler(|_ctx, args| {
            let a = args["a"].as_i64().unwrap_or(0);
            let b = args["b"].as_i64().unwrap_or(0);
            ToolResult::new(format!("{}", a + b))
        }))
    .action(action("multiply")
        .description("Multiply two numbers")
        .arg(ArgDef::int("a"))
        .arg(ArgDef::int("b"))
        .handler(|_ctx, args| {
            let a = args["a"].as_i64().unwrap_or(0);
            let b = args["b"].as_i64().unwrap_or(0);
            ToolResult::new(format!("{}", a * b))
        }))
    .register();

Documentation

License