Rust MCP SDK

A high-performance, asynchronous toolkit for building MCP servers and clients. Focus on your app's logic while rust-mcp-sdk takes care of the rest!

rust-mcp-sdk provides the necessary components for developing both servers and clients in the MCP ecosystem. Leveraging the rust-mcp-schema crate simplifies the process of building robust and reliable MCP servers and clients, ensuring consistency and minimizing errors in data handling and message processing.

rust-mcp-sdk supports all three official versions of the MCP protocol. By default, it uses the 2025-06-18 version, but earlier versions can be enabled via Cargo features.

This project supports following transports:

Stdio (Standard Input/Output)
Streamable HTTP
SSE (Server-Sent Events)

🚀 The rust-mcp-sdk includes a lightweight Axum based server that handles all core functionality seamlessly. Switching between stdio and Streamable HTTP is straightforward, requiring minimal code changes. The server is designed to efficiently handle multiple concurrent client connections and offers built-in support for SSL.

MCP Streamable HTTP Support

✅ Streamable HTTP Support for MCP Servers
✅ DNS Rebinding Protection
✅ Batch Messages
✅ Streaming & non-streaming JSON response
⬜ Streamable HTTP Support for MCP Clients
⬜ Resumability
⬜ Authentication / Oauth

⚠️ Project is currently under development and should be used at your own risk.

Usage Examples
Getting Started
HyperServerOptions
- Security Considerations
Cargo features
Choosing Between Standard and Core Handlers traits
- Choosing Between ServerHandler and ServerHandlerCore
- Choosing Between ClientHandler and ClientHandlerCore
Projects using Rust MCP SDK
Contributing
Development
License

Usage Examples

MCP Server (stdio)

Create a MCP server with a tool that will print a Hello World! message:

#[tokio::main]
async fn main() -> SdkResult<()> {

    // STEP 1: Define server details and capabilities
    let server_details = InitializeResult {
        // server name and version
        server_info: Implementation {
            name: "Hello World MCP Server".to_string(),
            version: "0.1.0".to_string(),
            title: Some("Hello World MCP Server".to_string()),
        },
        capabilities: ServerCapabilities {
            // indicates that server support mcp tools
            tools: Some(ServerCapabilitiesTools { list_changed: None }),
            ..Default::default() // Using default values for other fields
        },
        meta: None,
        instructions: Some("server instructions...".to_string()),
        protocol_version: LATEST_PROTOCOL_VERSION.to_string(),
    };

    // STEP 2: create a std transport with default options
    let transport = StdioTransport::new(TransportOptions::default())?;

    // STEP 3: instantiate our custom handler for handling MCP messages
    let handler = MyServerHandler {};

    // STEP 4: create a MCP server
    let server: ServerRuntime = server_runtime::create_server(server_details, transport, handler);

    // STEP 5: Start the server
    server.start().await

}

See hello-world-mcp-server example running in MCP Inspector :

MCP Server (Streamable HTTP)

Creating an MCP server in rust-mcp-sdk with the sse transport allows multiple clients to connect simultaneously with no additional setup. Simply create a Hyper Server using hyper_server::create_server() and pass in the same handler and HyperServerOptions.

💡 By default, both Streamable HTTP and SSE transports are enabled for backward compatibility. To disable the SSE transport , set the sse_support to false in the HyperServerOptions.

// STEP 1: Define server details and capabilities
let server_details = InitializeResult {
    // server name and version
    server_info: Implementation {
        name: "Hello World MCP Server".to_string(),
        version: "0.1.0".to_string(),
        title: Some("Hello World MCP Server".to_string()),
    },
    capabilities: ServerCapabilities {
        // indicates that server support mcp tools
        tools: Some(ServerCapabilitiesTools { list_changed: None }),
        ..Default::default() // Using default values for other fields
    },
    meta: None,
    instructions: Some("server instructions...".to_string()),
    protocol_version: LATEST_PROTOCOL_VERSION.to_string(),
};

// STEP 2: instantiate our custom handler for handling MCP messages
let handler = MyServerHandler {};

// STEP 3: instantiate HyperServer, providing `server_details` , `handler` and HyperServerOptions
let server = hyper_server::create_server(
    server_details,
    handler,
    HyperServerOptions {
        host: "127.0.0.1".to_string(),
        sse_support: false,
        ..Default::default()
    },
);

// STEP 4: Start the server
server.start().await?;

Ok(())

The implementation of MyServerHandler is the same regardless of the transport used and could be as simple as the following:

// STEP 1: Define a rust_mcp_schema::Tool ( we need one with no parameters for this example)
#[mcp_tool(name = "say_hello_world", description = "Prints \"Hello World!\" message")]
#[derive(Debug, Deserialize, Serialize, JsonSchema)]
pub struct SayHelloTool {}

// STEP 2: Implement ServerHandler trait for a custom handler
// For this example , we only need handle_list_tools_request() and handle_call_tool_request() methods.
pub struct MyServerHandler;

#[async_trait]
impl ServerHandler for MyServerHandler {
    // Handle ListToolsRequest, return list of available tools as ListToolsResult
    async fn handle_list_tools_request(&self, request: ListToolsRequest, runtime: &dyn McpServer) -> Result<ListToolsResult, RpcError> {

        Ok(ListToolsResult {
            tools: vec![SayHelloTool::tool()],
            meta: None,
            next_cursor: None,
        })

    }

    /// Handles requests to call a specific tool.
    async fn handle_call_tool_request( &self, request: CallToolRequest, runtime: &dyn McpServer, ) -> Result<CallToolResult, CallToolError> {

        if request.tool_name() == SayHelloTool::tool_name() {
            Ok( CallToolResult::text_content( vec![TextContent::from("Hello World!".to_string())]  ))
        } else {
            Err(CallToolError::unknown_tool(request.tool_name().to_string()))
        }

    }
}

👉 For a more detailed example of a Hello World MCP Server that supports multiple tools and provides more type-safe handling of CallToolRequest, check out: examples/hello-world-mcp-server

See hello-world-server-streamable-http example running in MCP Inspector :

MCP Client (stdio)

Create an MCP client that starts the @modelcontextprotocol/server-everything server, displays the server's name, version, and list of tools, then uses the add tool provided by the server to sum 120 and 28, printing the result.

// STEP 1: Custom Handler to handle incoming MCP Messages
pub struct MyClientHandler;

#[async_trait]
impl ClientHandler for MyClientHandler {
    // To check out a list of all the methods in the trait that you can override, take a look at https://github.com/rust-mcp-stack/rust-mcp-sdk/blob/main/crates/rust-mcp-sdk/src/mcp_handlers/mcp_client_handler.rs
}

#[tokio::main]
async fn main() -> SdkResult<()> {

    // Step2 : Define client details and capabilities
    let client_details: InitializeRequestParams = InitializeRequestParams {
        capabilities: ClientCapabilities::default(),
        client_info: Implementation {
            name: "simple-rust-mcp-client".into(),
            version: "0.1.0".into(),
        },
        protocol_version: LATEST_PROTOCOL_VERSION.into(),
    };

    // Step3 : Create a transport, with options to launch @modelcontextprotocol/server-everything MCP Server
    let transport = StdioTransport::create_with_server_launch(
        "npx",
        vec![ "-y".to_string(), "@modelcontextprotocol/server-everything".to_string()],
        None, TransportOptions::default()
    )?;

    // STEP 4: instantiate our custom handler for handling MCP messages
    let handler = MyClientHandler {};

    // STEP 5: create a MCP client
    let client = client_runtime::create_client(client_details, transport, handler);

    // STEP 6: start the MCP client
    client.clone().start().await?;


    // STEP 7: use client methods to communicate with the MCP Server as you wish

    // Retrieve and display the list of tools available on the server
    let server_version = client.server_version().unwrap();
    let tools = client.list_tools(None).await?.tools;

    println!("List of tools for {}@{}", server_version.name, server_version.version);

    tools.iter().enumerate().for_each(|(tool_index, tool)| {
        println!("  {}. {} : {}",
            tool_index + 1,
            tool.name,
            tool.description.clone().unwrap_or_default()
        );
    });

    println!("Call \"add\" tool with 100 and 28 ...");
    // Create a `Map<String, Value>` to represent the tool parameters
    let params = json!({"a": 100,"b": 28}).as_object().unwrap().clone();
    let request = CallToolRequestParams { name: "add".to_string(),arguments: Some(params)};

    // invoke the tool
    let result = client.call_tool(request).await?;

    println!("{}",result.content.first().unwrap().as_text_content()?.text);

    Ok(())
}

Here is the output :

your results may vary slightly depending on the version of the MCP Server in use when you run it.

MCP Client (sse)

Creating an MCP client using the rust-mcp-sdk with the SSE transport is almost identical, with one exception at step 3. Instead of creating a StdioTransport, you simply create a ClientSseTransport. The rest of the code remains the same:

- let transport = StdioTransport::create_with_server_launch(
-    "npx",
-    vec![ "-y".to_string(), "@modelcontextprotocol/server-everything".to_string()],
-    None, TransportOptions::default()
-)?;
+ let transport = ClientSseTransport::new(MCP_SERVER_URL, ClientSseTransportOptions::default())?;

Getting Started

If you are looking for a step-by-step tutorial on how to get started with rust-mcp-sdk , please see : Getting Started MCP Server

HyperServerOptions

HyperServer is a lightweight Axum-based server that streamlines MCP servers by supporting Streamable HTTP and SSE transports. It supports simultaneous client connections, internal session management, and includes built-in security features like DNS rebinding protection and more.

HyperServer is highly customizable through HyperServerOptions provided during initialization.

A typical example of creating a HyperServer that exposes the MCP server via Streamable HTTP and SSE transports at:

let server = hyper_server::create_server(
    server_details,
    handler,
    HyperServerOptions {
        host: "127.0.0.1".to_string(),
        enable_ssl: true,
        ..Default::default()
    },
);

server.start().await?;

Here is a list of available options with descriptions for configuring the HyperServer:

pub struct HyperServerOptions {
    /// Hostname or IP address the server will bind to (default: "127.0.0.1")
    pub host: String,

    /// Hostname or IP address the server will bind to (default: "8080")
    pub port: u16,

    /// Optional custom path for the Streamable HTTP endpoint (default: `/mcp`)
    pub custom_streamable_http_endpoint: Option<String>,

    /// This setting only applies to streamable HTTP.
    /// If true, the server will return JSON responses instead of starting an SSE stream.
    /// This can be useful for simple request/response scenarios without streaming.
    /// Default is false (SSE streams are preferred).
    pub enable_json_response: Option<bool>,

    /// Interval between automatic ping messages sent to clients to detect disconnects
    pub ping_interval: Duration,

    /// Shared transport configuration used by the server
    pub transport_options: Arc<TransportOptions>,

    /// Optional thread-safe session id generator to generate unique session IDs.
    pub session_id_generator: Option<Arc<dyn IdGenerator>>,

    /// Enables SSL/TLS if set to `true`
    pub enable_ssl: bool,

    /// Path to the SSL/TLS certificate file (e.g., "cert.pem").
    /// Required if `enable_ssl` is `true`.
    pub ssl_cert_path: Option<String>,

    /// Path to the SSL/TLS private key file (e.g., "key.pem").
    /// Required if `enable_ssl` is `true`.
    pub ssl_key_path: Option<String>,

    /// If set to true, the SSE transport will also be supported for backward compatibility (default: true)
    pub sse_support: bool,

    /// Optional custom path for the Server-Sent Events (SSE) endpoint (default: `/sse`)
    /// Applicable only if sse_support is true
    pub custom_sse_endpoint: Option<String>,

    /// Optional custom path for the MCP messages endpoint for sse (default: `/messages`)
    /// Applicable only if sse_support is true
    pub custom_messages_endpoint: Option<String>,

    /// List of allowed host header values for DNS rebinding protection.
    /// If not specified, host validation is disabled.
    pub allowed_hosts: Option<Vec<String>>,

    /// List of allowed origin header values for DNS rebinding protection.
    /// If not specified, origin validation is disabled.
    pub allowed_origins: Option<Vec<String>>,

    /// Enable DNS rebinding protection (requires allowedHosts and/or allowedOrigins to be configured).
    /// Default is false for backwards compatibility.
    pub dns_rebinding_protection: bool,
}

Security Considerations

When using Streamable HTTP transport, following security best practices are recommended:

Enable DNS rebinding protection and provide proper allowed_hosts and allowed_origins to prevent DNS rebinding attacks.
When running locally, bind only to localhost (127.0.0.1 / localhost) rather than all network interfaces (0.0.0.0)
Use TLS/HTTPS for production deployments

Cargo Features

The rust-mcp-sdk crate provides several features that can be enabled or disabled. By default, all features are enabled to ensure maximum functionality, but you can customize which ones to include based on your project's requirements.

Available Features

server: Activates MCP server capabilities in rust-mcp-sdk, providing modules and APIs for building and managing MCP servers.
client: Activates MCP client capabilities, offering modules and APIs for client development and communicating with MCP servers.
hyper-server: This feature enables the sse transport for MCP servers, supporting multiple simultaneous client connections out of the box.
ssl: This feature enables TLS/SSL support for the sse transport when used with the hyper-server.
macros: Provides procedural macros for simplifying the creation and manipulation of MCP Tool structures.

MCP Protocol Versions with Corresponding Features

2025_06_18 : Activates MCP Protocol version 2025-06-18 (enabled by default)
2025_03_26 : Activates MCP Protocol version 2025-03-26
2024_11_05 : Activates MCP Protocol version 2024-11-05

Note: MCP protocol versions are mutually exclusive—only one can be active at any given time.

Default Features

When you add rust-mcp-sdk as a dependency without specifying any features, all features are included, with the latest MCP Protocol version enabled by default:

[dependencies]
rust-mcp-sdk = "0.2.0"

Using Only the server Features

If you only need the MCP Server functionality, you can disable the default features and explicitly enable the server feature. Add the following to your Cargo.toml:

[dependencies]
rust-mcp-sdk = { version = "0.2.0", default-features = false, features = ["server","macros"] }

Optionally add hyper-server for sse transport, and ssl feature for tls/ssl support of the hyper-server

Using Only the client Features

If you only need the MCP Client functionality, you can disable the default features and explicitly enable the client feature. Add the following to your Cargo.toml:

[dependencies]
rust-mcp-sdk = { version = "0.2.0", default-features = false, features = ["client","2024_11_05"] }

Choosing Between Standard and Core Handlers traits

Learn when to use the mcp_*_handler traits versus the lower-level mcp_*_handler_core traits for both server and client implementations. This section helps you decide based on your project's need for simplicity versus fine-grained control.

Choosing Between `ServerHandler` and `ServerHandlerCore`

rust-mcp-sdk provides two type of handler traits that you can chose from:

ServerHandler: This is the recommended trait for your MCP project, offering a default implementation for all types of MCP messages. It includes predefined implementations within the trait, such as handling initialization or responding to ping requests, so you only need to override and customize the handler functions relevant to your specific needs. Refer to examples/hello-world-mcp-server/src/handler.rs for an example.
ServerHandlerCore: If you need more control over MCP messages, consider using ServerHandlerCore. It offers three primary methods to manage the three MCP message types: request, notification, and error. While still providing type-safe objects in these methods, it allows you to determine how to handle each message based on its type and parameters. Refer to examples/hello-world-mcp-server-core/src/handler.rs for an example.

👉 Note: Depending on whether you choose ServerHandler or ServerHandlerCore, you must use the create_server() function from the appropriate module:

For ServerHandler:
- Use server_runtime::create_server() for servers with stdio transport
- Use hyper_server::create_server() for servers with sse transport
For ServerHandlerCore:
- Use server_runtime_core::create_server() for servers with stdio transport
- Use hyper_server_core::create_server() for servers with sse transport

Choosing Between `ClientHandler` and `ClientHandlerCore`

The same principles outlined above apply to the client-side handlers, ClientHandler and ClientHandlerCore.

Use client_runtime::create_client() when working with ClientHandler
Use client_runtime_core::create_client() when working with ClientHandlerCore

Both functions create an MCP client instance.

Check out the corresponding examples at: examples/simple-mcp-client and examples/simple-mcp-client-core.

Projects using Rust MCP SDK

Below is a list of projects that utilize the rust-mcp-sdk, showcasing their name, description, and links to their repositories or project pages.

Name	Description	Link
Rust MCP Filesystem	Fast, async MCP server enabling high-performance, modern filesystem operations with advanced features.	GitHub
MCP Discovery	A lightweight command-line tool for discovering and documenting MCP Server capabilities.	GitHub
mistral.rs	Blazingly fast LLM inference.	GitHub
moon	moon is a repository management, organization, orchestration, and notification tool for the web ecosystem, written in Rust.	GitHub
angreal	Angreal provides a way to template the structure of projects and a way of executing methods for interacting with that project in a consistent manner.	GitHub
text-to-cypher	A high-performance Rust-based API service that translates natural language text to Cypher queries for graph databases.	GitHub
notify-mcp	A Model Context Protocol (MCP) server that provides desktop notification functionality.	GitHub
lst	`lst` is a personal lists, notes, and blog posts management application with a focus on plain-text storage, offline-first functionality, and multi-device synchronization.	GitHub

Contributing

We welcome everyone who wishes to contribute! Please refer to the contributing guidelines for more details.

Check out our development guide for instructions on setting up, building, testing, formatting, and trying out example projects.

All contributions, including issues and pull requests, must follow Rust's Code of Conduct.

Unless explicitly stated otherwise, any contribution you submit for inclusion in rust-mcp-sdk is provided under the terms of the MIT License, without any additional conditions or restrictions.

Development

Check out our development guide for instructions on setting up, building, testing, formatting, and trying out example projects.

License

This project is licensed under the MIT License. see the LICENSE file for details.

Name		Name	Last commit message	Last commit date
Latest commit History 113 Commits
.github		.github
assets		assets
crates		crates
doc		doc
examples		examples
.gitignore		.gitignore
.release-config.json		.release-config.json
.release-manifest.json		.release-manifest.json
CONTRIBUTING.md		CONTRIBUTING.md
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
Makefile.toml		Makefile.toml
README.md		README.md
development.md		development.md
rust-toolchain.toml		rust-toolchain.toml

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Rust MCP SDK

Table of Contents

Usage Examples

MCP Server (stdio)

MCP Server (Streamable HTTP)

MCP Client (stdio)

MCP Client (sse)

Getting Started

HyperServerOptions

Security Considerations

Cargo Features

Available Features

MCP Protocol Versions with Corresponding Features

Default Features

Using Only the server Features

Using Only the client Features

Choosing Between Standard and Core Handlers traits

Choosing Between `ServerHandler` and `ServerHandlerCore`

Choosing Between `ClientHandler` and `ClientHandlerCore`

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Rust MCP SDK

Table of Contents

Usage Examples

MCP Server (stdio)

MCP Server (Streamable HTTP)

MCP Client (stdio)

MCP Client (sse)

Getting Started

HyperServerOptions

Security Considerations

Cargo Features

Available Features

MCP Protocol Versions with Corresponding Features

Default Features

Using Only the server Features

Using Only the client Features

Choosing Between Standard and Core Handlers traits

Choosing Between ServerHandler and ServerHandlerCore

Choosing Between ClientHandler and ClientHandlerCore

Projects using Rust MCP SDK

Contributing

Development

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