Say it back in one sentence
Artifact: one honest sentence on what you now believe that you didn't before
1. The habit
At the end of every learning session — every one, even the five-minute ones — write down a single sentence in your own words:
What I now know that I didn't an hour ago.
One sentence. Plain language. No jargon you didn't actually understand. Not "I learned about hooks" — what about them, specifically, in your words, with the part that surprised you.
This is the final step of the loop. Skip it and the whole rep evaporates by next week.
2. Why it matters
The sentence does three things at once.
One: it forces compression. If you can't write the sentence, the thing isn't crystallized yet. You learned a vibe, not an idea.
Two: it makes the learning retrievable. A list of one-sentence summaries from your last hundred sessions is a study guide you'll actually re-read. Three notebooks of unstructured notes are not.
Three: it gives you something to test against future material. When the same idea comes up again, you can ask does this match my one-sentence summary, or contradict it? The contradiction is where the real refinement happens.
3. What the sentence is not
It is not a tweet you'd write to look smart. It is not a summary of the article. It is not "X is a way of doing Y." Anyone could write that without learning anything.
It is the specific thing you now believe and didn't before. Often it sounds simple. Oh — useEffect runs after render, not during. I thought it ran during. That's a good sentence. It's a specific belief you updated.
4. Try it
What did you learn from the units in this chapter so far? Don't think hard. The right answer is something specific that surprised you.
If your sentence is "I should predict before I run," that's good. If it's "I should learn better," you didn't actually update anything. Loop again.