It’s been a while since I tried it but I think I had a lot of difficulty with identifying Misskey client API. I had to to just query a couple published Misskey endpoints on a server and see if it responded in some valid way because at the time there wasn’t an obvious thing to query that just said “I support Misskey client API”. Part of the issue was that there was a new Misskey fork every fifteen minutes that changed the server identification, so if I didn’t recognize the server identification I had to start that exploration process to see what it supported, if any. In particular, streaming APIs. I canceled the project when Mastodon disabled streaming API access without warning (not a scraper or search engine, it was a game that dynamically generated player maps based on server activity.)