Rust MCP Schema

Add the crate as a dependency in your Cargo.toml. By default it includes the latest stable MCP schema version (2025-11-25) and the schema_utils module.

[dependencies]
rust-mcp-schema = "0.10.1"

If you need a specific protocol version, disable default features and enable the version you target. This is important for compatibility with specific MCP clients.

[dependencies]
rust-mcp-schema = { version = "0.10.1", default-features = false, features = ["2025_06_18"] }

Import ClientMessage and ServerMessage from the crate to handle incoming and outgoing MCP protocol messages with full type safety and serde deserialization.

use rust_mcp_schema::{ClientMessage, ClientRequest, schema_utils::ResultFromServer};
use std::str::FromStr;

let message = ClientMessage::from_str(&message_payload)?;
if let ClientMessage::Request(req) = message {
    if let ClientRequest::InitializeRequest(init) = req {
        // Handle initialization
    }
}

Use the typed request and response structs to implement tool handlers, resource providers, and prompt handlers. The schema_utils module provides helper methods to construct valid ServerMessage responses.

Compile your project and test it against an MCP client. Use cargo test for unit tests and connect a real client like Claude Desktop for integration testing.

cargo build
cargo test