MCP Server implementation for Poem

Example

[dependencies]
poem-mcpserver.workspace = "*"
serde = { version = "1.0", features = ["derive"] }
schemars = "0.8.22"

use poem_mcpserver::{stdio::stdio, tool::Text, McpServer, Tools};

struct Counter {
    count: i32,
}

/// This server provides a counter tool that can increment and decrement values.
///
/// The counter starts at 0 and can be modified using the 'increment' and
/// 'decrement' tools. Use 'get_value' to check the current count.
#[Tools]
impl Counter {
    /// Increment the counter by 1
    async fn increment(&mut self) -> Text<i32> {
        self.count += 1;
        Text(self.count)
    }

    /// Decrement the counter by 1
    async fn decrement(&mut self) -> Text<i32> {
        self.count -= 1;
        Text(self.count)
    }

    /// Get the current counter value
    async fn get_value(&self) -> Text<i32> {
        Text(self.count)
    }
}

#[tokio::main]
async fn main() -> std::io::Result<()> {
    stdio(McpServer::new().tools(Counter { count: 0 })).await
}

Safety

This crate uses #![forbid(unsafe_code)] to ensure everything is implemented in 100% Safe Rust.

MSRV

The minimum supported Rust version for this crate is 1.85.0.

Contributing

:balloon: Thanks for your help improving the project! We are so happy to have you!

License

Licensed under either of

• Apache License, Version 2.0,(LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Poem by you, shall be licensed as Apache, without any additional terms or conditions.