Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives clear context on the expected input forms and a workflow hint (from article search results, get detail first, then use post.share_url or post.post_id). The url parameter description further excludes video links, other links, and user profile links, which guides correct use. It does not explicitly name sibling alternatives, but the by_url/by_post_id distinction is clear from the tool name and schema.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.