An official Go SDK for MCP that praises its predecessors

What it does

Implements the canonical Go bindings for the Model Context Protocol, split into focused packages: mcp for client and server construction, jsonrpc for custom transport authors, and auth/oauthex for OAuth primitives and extensions like ProtectedResourceMetadata. It targets full spec compliance and supports multiple MCP specification versions concurrently.

The interesting bit

The SDK wears its lineage openly: the README explicitly credits third-party predecessors such as mcp-go and mcp-golang as “viable alternatives,” suggesting this official library is trying to synthesize rather than supplant a thriving community. The version compatibility matrix also reveals the difficulty of keeping pace with a moving spec—client-side OAuth and sampling with tools remain experimental or partially supported even in recent releases.

Key highlights

• Modular package layout separates core APIs, JSON-RPC transport plumbing, and OAuth concerns
• Supports four iterations of the MCP specification, from 2024-11-05 through 2025-11-25
• Client-side OAuth and ProtectedResourceMetadata extensions ship in dedicated auth packages
• New contributions fall under Apache 2.0, though existing code retains an MIT license
• Ships with examples for stdio-based server and client wiring

Caveats

• Support for the latest 2025-11-25 spec is flagged as experimental or partial depending on version; client-side OAuth and sampling with tools are notably unfinished
• The README notes the SDK “endeavors to implement the full MCP spec,” which is an aspiration rather than a completed guarantee

Verdict

Worth evaluating if you want an officially blessed, Google-adjacent foundation with explicit spec version tracking. If you are already productive with a third-party alternative like mcp-go, the README itself suggests staying put is a reasonable choice.