Say it in fewer bytes.
A hundred and fifty-five small problems, in three tiers. Write an expression in terms of
x that solves each one, and the engine judges it as you type,
against the examples on screen and a few more besides. The score is the number of
characters. The warm-ups are two or three; the hardest run past thirty.
…
you — · par —How the judging works
Your expression becomes a one-argument function and is run against
every test by the engine itself. The comparison is ~, match,
rather than =, so 1 2 3 and 1 2 3.0 are not the same
answer, and something of the wrong shape cannot slip through by conforming.
A half-written expression is judged rather than thrown, because golf is typed one character at a time and most of what the judge sees is not valid yet. An error just means no test passed.
The extra tests are not on screen, though nothing about them is secret: the
judge runs in your browser, so every case ships with the page and anyone who opens
assets/golf/puzzles.js can read them. They are out of the way, not hidden
from you, and there is nowhere to hide them.
Par is a known short solution, not a proven minimum. If you get under it, you have found something better, and the share link carries your expression so you can prove it.