Crate neva 

Neva

Easy configurable MCP server and client SDK for Rust

Dependencies

[dependencies]
neva = { version = "0.2.1", features = ["full"] }
tokio = { version = "1", features = ["full"] }

Example Server

use neva::App;
 
#[tokio::main]
async fn main() {
    let mut app = App::new()
        .with_options(|opt| opt
            .with_stdio());
 
    app.map_tool("hello", |name: String| async move { 
        format!("Hello, {name}!")
    });
 
    app.run().await;
} 

Example Client

use std::time::Duration;
use neva::{Client, error::Error};
 
#[tokio::main]
async fn main() -> Result<(), Error> {
    let mut client = Client::new()
        .with_options(|opt| opt
            .with_stdio("npx", ["-y", "@modelcontextprotocol/server-everything"]));
 
    client.connect().await?;
 
    // Call a tool
    let args = [("message", "Hello MCP!")];
    let result = client.call_tool("echo", Some(args)).await?;
    println!("{:?}", result.content);
 
    client.disconnect().await
}

Re-exports

pub use app::App;

pub use app::context::Context;

pub use client::Client;

Modules

app

Represents an MCP application

auth

Authentication utilities

client

Utilities for the MCP client

commands

List of built-in commands supported by the MCP protocol

di

Types and utilities for dependency injection

error

Represents an error

json

JSON utilities

macros

Utilities for macros

middleware

MCP Server middleware utilities

prelude

Prelude with commonly used items

shared

Shared utilities for server and client

transport

Transport protocols and utilities for communicating between server and client

types

Types used by the MCP protocol

Macros

spawn_fair

Cooperatively yields to the Tokio scheduler before spawning a new task, ensuring fair task scheduling especially under high load or on platforms like Windows where newly spawned tasks may not execute promptly.

Attribute Macros

completion

Maps the completion function

elicitation

Maps the elicitation handler function

handler

Maps the function to a command handler

json_schema

Provides a utility to extract a JSON schema of this type

prompt

Maps the function to a prompt

resource

Maps the function to a resource template

resources

Maps the list of resources function

sampling

Maps the sampling handler function

tool

Maps the function to a tool