Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, the description fully compensates by enumerating the returned meeting fields (id, provider, title, transcript, summary, share_url, meeting_url, attendees, speakers, duration) and the no-match case. An agent has everything needed to call and consume the result.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.