tachyon

[](https://central.sonatype.com/search?q=dev.tachyonmcp%2Ftachyon-*) [](http://java.com) [](https://github.com/tachyonmcp/tachyon/actions/workflows/build.yml) [](https://github.com/modelcontextprotocol/conformance) [](https://codecov.io/github/tachyonmcp/tachyon) [](https://tachyonmcp.dev/docs/) [](https://apidocs.tachyonmcp.dev/) [](https://github.com/tachyonmcp/tachyon/wiki) [](https://deepwiki.com/tachyonmcp/tachyon) <div style="align-content: center"> <img src="docs/assets/social-banner.jpg" alt="Tachyon MCP banner" style="width: 100%; height: auto;border-radius: 10px" /> </div> **[Tachyon MCP](https://tachyonmcp.dev)** is a Java 21+ server runtime for the [Model Context Protocol](https://modelcontextprotocol.io). 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](tachyon-bom) once to pin the version, then add the core dependency: ```xml <dependencyManagement> <dependencies> <dependency> <groupId>dev.tachyonmcp</groupId> <artifactId>tachyon-bom</artifactId> <version>${tachyon.version}</version> <!-- get latest version from Maven Central --> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>dev.tachyonmcp</groupId> <artifactId>tachyon-core</artifactId> </dependency> </dependencies> ``` Create and start a server: ```java 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](docs/quickstart.md) for Java and Kotlin examples plus a `curl` test. ## Implemented features | Area | Support | |---|---| | **MCP surface** | Tools, resources and templates, prompts, completions, logging, sampling, form/URL elicitation, cancellation, subscriptions, pagination, and progress notifications | | **Annotations** | Optional adapters for [mcp-java, LangChain4j, and Spring AI](docs/annotations.md), mapped onto Tachyon's standard registries | | **Tasks** | Full `tasks/*` lifecycle, state validation, status notifications, retention, and `TasksExtension` for [SEP-2663](docs/extensions/tasks.md), with SEP-1686 compatibility for MCP 2025-11-25 clients | | **Agent Skills** | `SkillsExtension` implements the [SEP-2640](docs/extensions/skills.md) draft: filesystem/classpath registries, `skill://` resources, `skills/list`, `skills/get`, and directory reads | | **Extensions** | [SEP-2133](docs/extensions/) negotiation, custom JSON-RPC methods, capability advertisement, and extension-gated features | | **Runtime** | Stateless or resumable sessions, `Last-Event-ID` replay, pluggable stores, virtual-thread handlers, request timeouts, and graceful draining | | **Observability** | OpenTelemetry spans and metrics via `tachyon-opentelemetry`, following the [MCP semantic conventions](https://github.com/open-telemetry/semantic-conventions-genai/tree/main/model/mcp), plus an opt-in payload capture policy -- see [docs](docs/running/observability.md) | | **Java and Kotlin** | Independent sync/async Java contracts and a coroutine-first [Kotlin DSL](docs/kotlin/) | | **Testing** | Official conformance suites plus a [testkit](docs/testkit.md) for dynamic servers and fluent JSON-RPC assertions | ## Documentation and examples - [Configuration](docs/running/configuration.md) -- network, native I/O, sessions, CORS, and runtime limits - [Observability](docs/running/observability.md) -- observation listeners, payload capture policy, and the bundled OpenTelemetry integration - [Tools](docs/features/tools.md), [resources](docs/features/resources.md), and [tasks](docs/extensions/tasks.md) -- feature APIs and examples - [Annotations](docs/annotations.md) -- mcp-java, LangChain4j, and Spring AI providers - [Extensions](docs/extensions/) and [MCP Skills](docs/extensions/skills.md) -- custom protocol methods and SEP support - [Kotlin DSL](docs/kotlin/) -- builders, scopes, and suspending handlers - [Examples](examples/README.md) -- runnable Java and Kotlin servers - [FAQ](docs/faq.md) -- 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. ```shell npx skills add tachyonmcp/tachyon --skill tachyon-mcp ``` Its Java and Kotlin examples are compiled during the project build to keep them current. See the [agent skill guide](docs/agent-skill.md) for install options and example prompts. ## License **Tachyon MCP** is available under the terms of the [Apache 2.0](LICENSE).