Three things the card system did not have.
**Spaced repetition.** There was none. "Known" and "to review" were React state
that vanished on reload, so a deck of two hundred was two hundred cards every
time and the only spacing was whichever cards a learner remembered to skip.
Verdicts are now kept, and the deck comes back in the order the learner's own
history calls for: due first, most decayed first, then never seen, then the
rest — because somebody who has met the whole deck recently should still get a
deck rather than a screen saying come back on Thursday.
It borrows the question player's arithmetic rather than choosing its own.
`recall_probability`, `DUE_RECALL`, the thirty-day half-life: two schedulers
with two ideas of "due", in one product that shows a learner one readiness
number, is how the number stops meaning anything. Two outcomes and no
four-point scale — a scale asks a learner to rate their own recall in units
they have never calibrated, and the extra resolution is noise.
**Cards are prose.** Both faces go through the same renderer as everything
else, so a card can carry `[[264|respiratory failure]]`, a `==key point==`, a
teaching tip or a figure. That is most of what "link cards to things" turns out
to mean.
**A deck is reachable from the question.** Beside the topic-reading chip under
the correct answer, one chip per linked deck. Read from the question's end
only, deliberately: a card that listed the questions it belongs to would hand a
learner revising the deck the shape of the exam, and the answer with it.
Migration m3d4e5f6a7b8.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TqXevQJhxFrM7jJg82cgZN
04abd78380