Does the description explain when to use this tool, when not to, or what alternatives exist?
The parameter description provides strong usage context: pass author.profile_url from search/detail/comment results, and avoid channel_id, bare @usernames, channel names, video links, playlist links, or search page links. However, it does not explicitly discuss when to choose this tool over the sibling video-focused tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.