andreban

It is worth setting the expectation in the CheatSheet that WebMCP is in early preview, under active development and the API surface is changing frequently as a result of that, otherwise users of the cheatsheet might be surprised when some of the APIs documented there don't work.

And that's exactly the goal. There's no recommendation against using features that are not in Baseline - and there is a superset of features that are progressive enhancement or polyfilllable, but those are much more use-case dependent - Progressive Enhancement frequently depends on the use case, and Polyfills vary the impact they have on performance, so need more care.