MCP Kotlin SDK

license

Apache-2.0(OSI

source

public(the client and server artefacts and their examples)

self-host

yes(a library you build against)

core features withheld

no — nothing withheld from the published tree

MCP Kotlin SDK is open source under the Model Context Protocol project's dual transition licence: Apache-2.0 for new contributions, MIT retained where consent to relicense was not given. A README badge says Apache-2.0 and Maven Central says MIT; the LICENSE file itself, which carries both texts, is what this record follows.

• https://api.github.com/repos/modelcontextprotocol/kotlin-sdk recorded 2026-09-17

  Repository metadata: 1,458 stars, not archived, not a fork, last pushed 2026-09-17, description "The official Kotlin SDK for Model Context Protocol servers and clients. Maintained in collaboration with JetBrains."

• https://raw.githubusercontent.com/modelcontextprotocol/kotlin-sdk/main/LICENSE recorded 2026-09-17

  The LICENSE body, read rather than the classifier's label. It opens "The MCP project is undergoing a licensing transition from the MIT License to the Apache License, Version 2.0", licensing new contributions Apache-2.0 and retaining MIT where relicensing consent was not given. That preamble is what GitHub's classifier cannot match, and it is why the API reports NOASSERTION.

Maven Central publishes no download figures for this artifact, and the legacy Solr search index used to estimate them returns nothing for this group either, leaving GitHub stars as the only comparable adoption signal. A star is not a use, so the true reach of a library used this way is likely undercounted.

• https://api.github.com/repos/modelcontextprotocol/kotlin-sdk recorded 2026-09-17

  Repository metadata for modelcontextprotocol/kotlin-sdk: 1,458 stargazers.

MCP Kotlin SDK implements both roles, the full primitive set and four transports - stdio, SSE, Streamable HTTP and WebSocket - matching mcp-python-sdk. All three optional features are documented, but the README names no dated specification revision, only linking to the "latest," the same gap as the C# SDK.

• https://raw.githubusercontent.com/modelcontextprotocol/kotlin-sdk/main/README.md recorded 2026-09-17

  The README: "Build MCP clients that can connect to any MCP server" and "Create MCP servers that expose resources, prompts, and tools", a feature table covering Prompts, Resources and Tools, and "Use standard transports like stdio, SSE, Streamable HTTP, and WebSocket". The client capability table lists sampling, roots and elicitation. No dated specification revision appears; it links to the specification's "latest".