Claude struggles with temporal reasoning (day-of-week, date mapping)

Claude frequently makes errors when reasoning about temporal relationships — mapping dates to days of the week, determining "today vs yesterday vs tomorrow", and keeping day names consistent with calendar dates in conversation.

This is particularly problematic in domains where day-of-week logic is critical (scheduling, market calendars, cycle state machines). The model can implement correct temporal code but then make wrong temporal claims in its own explanations to the user.

Suggestion: Temporal assertions in natural language responses should be verified against the same logic the model would use when writing code.