I’d like to be able to include a short text note to be shown on my profile (for example, via special notation). It could look like “bio” feature on social networks.

Good idea. IIRC we even discussed a notation to set the color on the profile page! A bio notation shouldn't take long to implement.

Given that we have a notation namespace, I'm thinking:

bio@ariadne.id="This is my bio"

Pinging @wiktor

I don’t understand how quotes work here. Are they needed at all? Quotes bring some unintuitive questions like “how does escaping work?” and “are \n allowed?”. Given that notation is an arbitrary string encoded in UTF-8 (per RFC 4880, section 5.2.3.16), quotes seem to be unnecessary.

Great! Thanks for checking the spec, so yeah, forget the quotes 🙂

Should it be dummy “claim” on doipjs level or a separate field?

I think we'd better make it an actual field in the returned object. I'd rather try and document it first and then implement. I really long for that rewrite. I'll see what I can do ASAP