There is no next lesson. That was the course.
- →A retrieval system over documents you actually have, with an honest account of where it fails.
- →The same system with a tool and a bounded loop, and a measured answer to whether the loop earned its cost.
- →The production version: a stated constraint, a cache with a correct key, a trust boundary, logs that explain a bad answer a week later, and a one-page ops note.
That is not course-shaped knowledge. It is the actual day-one loop of the job: build with a model, distrust it correctly, measure it, and keep it standing on a bad day.
A word before you go. Interviews have luck in them, and nobody can prepare the luck away. But everything on the other side of luck, the judgement, the numbers, the habit of saying how you would know it works, you now carry with you, and none of it can be taken back out. Walk in knowing that. We mean it entirely without irony: all the best, and go get it.
And one small ask. This site runs no ads and buys none; it grows when one engineer tells another it was worth their time, or it does not grow at all. If the course earned it, pass it to a friend who is preparing, the way someone probably once passed something to you. If it did not earn it, tell us why, and we will take that seriously too.