MHS basics
Is MHS open source today?
The core specification remains a limited research preview; public evidence must be labelled carefully.
The core MHS specification is not yet broadly available as a finished open-source standard. Anthropic introduced it as a research preview and said broader release depends on safety evaluation and practical best practices.
That is why MHS hub separates verified public implementations, official announcements, adjacent open-source technology, and community claims. An announced intention to support MHS is not presented as a working public implementation.
Check the evidence link and last review date on every project page before relying on a listing.