S26.E0924 – An AI Said the Function Didn't Exist. It Did. Four Errors in Four Hours.

Claude Opus 5 made four confident, plausible, completely wrong claims during a single development session. None were caught by better reasoning. Each was caught by reading a primary source at the moment the answer felt already known.
The client was World of Warcraft: Forever, build 69913 — a beta where most legacy Lua APIs have been removed and the survivors were kept inconsistently. The training data describes a game that no longer exists.
Error 1 — An API documented as absent. The project's own notes recorded "zero occurrences in this client's surface" as established fact. A three-line…