[Bluestein]

> "513: Your Coding Assistant Is Wrong"

You made me chuckle. Well played. Great stuff :)

May I, simply, also suggest:

HTTP 407 Hallucination

Meaning: The server understands the request but believes it to be incongruous with reality.-

[LiKao]

Yes, it should definitely be in the 400 space of HTML error codes. As 400 -> "You are incorrect" while 500 -> "We messed up".