@mike hmmmmmmmmmmmmmmm. I just tested and Mastodon accepts Create{Note} without it just fine.

Though as far as JSON-LD contexts go, I need to figure out this part. I'll probably have to do real networking in my JSON-LD processor in these edge cases even though I'd very much rather not. (I tried to sidestep it by downloading known contexts and putting them into my jar and matching them to hardcoded URLs but that clearly isn't working with all implementations)