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Rust MCP Utils

This project extends the rust-mcp-sdk with additional conveniences for building MCP servers in Rust with a defined set of tools. It provides two crates:

• mcp-utils - Higher-level traits and abstractions that simplify tool definition and server setup beyond the base SDK
• mcp-cli-builder - Command-line interface generation for MCP servers built with mcp-utils

Both crates are built on top of rust-mcp-sdk and provide ergonomic wrappers around its core functionality.

Derive one of the tool traits from mcp-utils to get:

• quick server setup: list your tools in setup_tools! and automatically get a server that can list your tools and handle tool calls
• switch between async or not: no need to adjust anything beside the tool trait you implement
• flexible output: return Result objects, plain strings, or anything that implements Serialize

Installation

Add the crates to your dependencies:

cargo add mcp-utils mcp-cli-builder

Defining Tools

The mcp-utils crate provides several tool trait options you can implement:

• TextTool – Returns plain text responses (synchronous)
• StructuredTool – Returns structured JSON data (synchronous)
• AsyncTextTool – Returns plain text responses (asynchronous)
• AsyncStructuredTool – Returns structured JSON data (asynchronous)

Create tools by implementing one of these traits with the #[mcp_tool] attribute:

use mcp_utils::tool_prelude::*;

#[mcp_tool(
    name = "example_tool",
    description = "An example tool for demonstration",
    title = "Example Tool",
    idempotent_hint = true,
    read_only_hint = true,
    destructive_hint = false,
    open_world_hint = false,
)]
#[derive(Debug, JsonSchema, Serialize, Deserialize)]
pub struct ExampleTool {
    /// A message to process
    pub message: String,
}

impl TextTool for ExampleTool {
    type Output = String;

    fn call(&self) -> Self::Output {
        format!("Processed: {}", self.message)
    }
}

The attribute macro mcp_tool is re-exported from the rust-mcp-sdk crate. You can find the available options to use in its documentation.

Aggregating Tools

Use the setup_tools! macro to create a tool collection. Map each tool to its kind like in the following example:

use mcp_utils::server_prelude::*;

setup_tools!(pub MyTools, [
    text(SimpleGreeter), // for TextTool
    structured(TestTool), // for StructuredTool
    async_text(FileReader), // for AsyncTextTool
    async_structured(DataProcessor), // for AsyncStructuredTool
]);

This will generate a set of tools named MyTools that you can pass to the CLI builder to initialize the MCP server.

Command Line Builder

Generate a command-line interface that handles the MCP server startup. This will build a command line parser using clap with:

• options to start the server in stdio mode or with server-sent events (with --host and --port)
• a clear help command which includes the available tools.
• an option to change the default request timeout (in humantime format)

use mcp_utils::server_prelude::*;

// Aggregate your tools together
setup_tools!(pub MyTools, [
    text(ExampleTool),
    // ...
]);

fn main() -> Result<(), String> {
    let server = ServerBuilder::new()
        .with_name(env!("CARGO_PKG_NAME")) // uses the name from Cargo.toml
        .with_version(env!("CARGO_PKG_VERSION")) // uses the version from Cargo.toml
        .with_title("My MCP Server")
        .with_instructions("A demonstration MCP server");

    mcp_cli_builder::run::<MyTools>(server)
}

License

This project is available under the MIT license. See LICENSE.txt for details.