current_time
Reading the clock — the one fact a model cannot infer.
A language model has no sense of time. Asked the hour with nothing in its context, it does not stay silent: it produces a plausible answer, because a plausible answer is what it was trained to produce. The user then acts on a time that was invented.
The system prompt carries a stamp taken when it was built, which is enough for "what day is it" and wrong by the length of the conversation for "what time is it". This tool is the second half: a clock that can be read again.
Deliberately read-only and free. The assistant should reach for it without hesitating, because hesitating is how it ends up guessing instead.