“Schedule it for the Friday after next” is one of the most dangerous strings you can hand a language model, because it will confidently return a date, that date will be well formatted, and there is roughly no chance anyone downstream will check it.
The model has no clock
Start with the thing that is easy to forget: a language model is a pure function of its context. It has no system clock, no timezone database access at inference time and no notion of when “now” is. If the current date is not in the context, the model does what it does with any missing variable — it infers a plausible one from the distribution, which means from the density of dates in its training data.
So a model asked for “next Tuesday” with no anchor is computing an offset from a guess, and the guess skews towards its training cutoff. Worse, models will often state the assumed date confidently, or not state it at all, which removes the one signal a reviewer could have used. This is a hallucination in the strict sense: a specific claim about the world, produced with no information behind it.
The four failures
