Rule 20 of 33 · Chapter IV — How We Build and Review
Automate the boring gate, save humans for judgment
Why this rule exists
Human attention is our scarcest and most valuable resource, and spending it on things a machine does better, checking formatting, catching lint violations, running the test suite, is a waste that also does the job worse, because machines never get tired or distracted or generous at 6pm on a Friday. Every mechanical check we automate is one fewer thing a reviewer has to hold in their head, freeing their limited attention for the things only humans can judge: is this the right approach, does this design make sense, will this be understandable in a year. A green check that says 'the objective stuff passed' lets review be about substance instead of nitpicking whitespace. Automation is also more consistent and less political, because 'the linter says so' avoids the tedious human arguments over style that generate heat and no light. The point isn't to remove humans from the loop, it's to point them at the part of the loop where they're irreplaceable.
In practice
Put the objective, mechanical checks into CI: formatting, linting, type checks, the test suite, and let them block merges automatically so no human has to police them. Make the checks fast, because a slow pipeline is one people learn to bypass or ignore. Then, in human review, deliberately skip the stuff the machine already covered and focus on design, correctness, clarity, and whether this is even the right thing to build. When you find yourself making the same review comment repeatedly, that's a candidate to automate, so the machine catches it next time and you never have to say it again. Keep the automated gate honest and green, since a suite that's flaky or always red trains everyone to ignore it, which is worse than not having it.
When it doesn't apply
Automation has limits; a green pipeline means the mechanical stuff passed, not that the change is correct or wise, so never let a passing build substitute for real human judgment on anything that matters. And don't automate a check so strict it blocks reasonable work more than it helps.