[flir]

In theory you can go even smaller: a way of measuring output, and a regular retrospective to improve the process. In other words, a feedback loop that improves your process over time.

Of course it would be dumb not to include all the stuff you mentioned at the start, because we've learned from previous projects that it works. Might as well stand on the shoulders of giants. But it's not the absolute, minimal core.

Personally I'm not convinced that "tighten your feedback loop" is good advice, because I interpret it as "shorter measurement intervals", and the shorter they are the more noise there is in the measurement. But the beauty of iterating the process is that we can try it and see if it works.