If I wanted to recommend to someone the min-maxed, highest density thing they could add to their prompt, it would simply be the time your current prompt appeared + the amount of time the last command you ran took.
These two pieces of information together make it very easy for you (or your local sysadmin (or an LLM looking over your digital shoulder)) to piece together a log of exactly what happened when. This kind of psuedo-non-repudiation can be invaluable for debugging sessions when you least expect it.
This was a tip I distilled from Michael W. Lucas's Networking for System Administrators a few years ago, which remains my preferred recommendation for any developers looking to learn just enough about networking to not feel totally lost when talking to an actual network engineer.
Bonus nerd points if you measure time in seconds since the UNIX epoch. Very easy and fast to run time delta calculations if you do that:
[0 1719242840] $ echo "foo"
[0 1719242905] $ echo "fell asleep before hitting enter" && sleep 5
[5 1719242910] $