field notes
Short notes from real engineering work: one decision, one incident, one reversal at a time. Each one names the shape of the problem, the tension that made it hard, the decision, and what it cost. The internals stay out — the codename is the hint.
If you have five minutes rather than an afternoon: the three case studies condense this material to one problem, one decision and what the decision cost. The notes below are the record those studies cite — and the projects the codenames belong to are on the front page.
A filter that decides which candidates reach the live path had been fitted offline, in one language, against historical data. It had to run in the live path, in another. Between the fit and the decision sits a translation, and a translation…
method
Not a changelog entry and not a repository summary. One decision, one incident, one reversal, or one hard-won invariant — the thing an engineer would tell you at a whiteboard.
Prefer records with dates and root causes? Those are on incidents. Live numbers are on stats.