It doesn’t contain any information at all about the structure of the JSON output. Is this a greenfield endpoint and anything will work is does it need to conform to an existing API? What about response codes for different failure modes? What about logging?
Your comment exemplifies what a lot of people complain about vibe coding: it works great for greenfielding CRUD apps, but it’s a bitch to use in a real code base.
If it's not a greenfield project, the Agent will go and look at the other endpoints and mimic the style as much as possible. Just like a human would.
"But we have documentati..." then give the Agent access to the same docs as humans and it'll use them.