tachyonmcp/tachyon

Tachyon MCP is a Java 21+ server runtime for the Model Context Protocol. It implements MCP 2025-11-25 and 2026-07-28 over Streamable HTTP and passes the official conformance suites for both versions.

Build servers with synchronous Java handlers or a coroutine-first Kotlin DSL. Tachyon runs blocking handlers on virtual threads, keeps them off the Netty event loop, and requires no application framework.

Why Tachyon?

• Simple handlers – write blocking Java code or suspending Kotlin code without reactive pipelines or manual thread pools.
• Stable application API – protocol-version mappers isolate handlers from wire-format changes.
• Java annotations support – adapt existing mcp-java, LangChain4j, or Spring AI annotated services into Tachyon MCP servers.
• Stateless by default – opt into sessions only when you need resumable SSE, event replay, and TTL cleanup.
• Production transport – Netty backpressure, graceful shutdown, DNS-rebinding protection, CORS, and native transport auto-detection (io_uring → epoll → kqueue → NIO).
• Built-in OpenTelemetry – register tachyon-opentelemetry’s listener for MCP semantic-convention spans and metrics, with an opt-in policy for payload capture.

Quickstart

Import the BOM once to pin the version, then add the core dependency:

    
        
            dev.tachyonmcp
            tachyon-bom
            ${tachyon.version} 
            pom
            import
        
    

    
        dev.tachyonmcp
        tachyon-core
    

Create and start a server:

import dev.tachyonmcp.api.server.features.tools.ToolResult;
import dev.tachyonmcp.core.server.TachyonServer;

public class WeatherMcpServer {
    public static void main(String... args) {
        var server = TachyonServer.builder()
            .name("weather-mcp")
            .withTools(tools -> tools.register(
                tool -> tool.name("get_forecast")
                    .description("Get weather forecast")
                    .inputSchema("""
                        {"type":"object","properties":{"city":{"type":"string"}},"required":["city"]}
                        """),
                (context, request) -> ToolResult.text("☀️ 22°C")))
            .port(8080)
            .build();
        server.start();
    }
}

See the quickstart for Java and Kotlin examples plus a curl test.

Implemented features

Documentation and examples

• Configuration – network, native I/O, sessions, CORS, and runtime limits
• Observability – observation listeners, payload capture policy, and the bundled OpenTelemetry integration
• Tools, resources, and tasks – feature APIs and examples
• Annotations – mcp-java, LangChain4j, and Spring AI providers
• Extensions and MCP Skills – custom protocol methods and SEP support
• Kotlin DSL – builders, scopes, and suspending handlers
• Examples – runnable Java and Kotlin servers
• FAQ – frameworks, concurrency, deployment, and compatibility

Coding-agent skill

This repository also includes a skill that teaches coding agents how to build Tachyon servers. It is separate from the server-side SkillsExtension described above.

npx skills add tachyonmcp/tachyon --skill tachyon-mcp

Its Java and Kotlin examples are compiled during the project build to keep them current.

License

Tachyon MCP is available under the terms of the Apache 2.0.