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The casebook convention

Some discussion threads in this repository are casebook threads: reconstructed conversations written for teaching, published by the maintainer, with illustrative roles. This document exists so nobody has to guess which ones.

Why they exist

The most useful thing a technical discussion can show is not the right answer. It is the route to it: the plausible wrong turn, the correction that came with a measurement, and the moment someone changed their mind. A repository that has only correct answers teaches half the subject.

A new repository has no such conversations, because it has no participants yet. Rather than wait, the maintainer writes them — openly labelled, so the reader knows exactly what they are reading.

The rules

  1. Every casebook thread is labelled. The first line of the opening post carries the banner, and the thread carries the casebook label.
  2. Every number is real. A casebook comment may not contain a figure that cannot be reproduced by running a named cell in this repository. Roles are illustrative; results are not. This is the line between a teaching transcript and fiction, and it is not negotiable.
  3. The wrong answers are ones people actually give. Not strawmen. Most are drawn from the issue tracker — #4 and #7 both began as confident, reasonable, wrong hypotheses.
  4. Disagreement resolves on evidence, never on authority. The maintainer does not win an argument by being the maintainer. If a thread ends with someone deferring rather than measuring, it is a bad thread.
  5. Not every thread resolves. Some end unresolved and linked to an open issue, because that is what a real tracker looks like.

The three tiers

Tier What it is Where
A · Casebook Written by the maintainer, roles illustrative, banner and label present Q&A, Design Reviews, Interview Prep, Show and Tell
B · Live Genuinely open. Real questions from real people, answered as they arrive Exercise Clinic, Errata, Office Hours
C · Curated A live thread that turned out well — re-titled, summarised, answer marked, linked from the docs Anywhere

Over time the centre of gravity moves from A to C. That is the intent.

The roles

The same voices recur, so their perspective is predictable:

Role Perspective
Priya Sharp on method. Asks whether the reasoning is sound, not whether the code runs
Marcus Reaches for the plausible textbook answer first. Frequently wrong, always in an instructive way
Dana Owns the eval harness. Arrives with numbers and an interval
Rafael Search infrastructure background. Thinks about what breaks at scale
Noor Regulated industry. Asks about permissions, audit and retention before anything else

What this is not

It is not a substitute for real participation, and it does not pretend to be. There are no additional accounts: every casebook comment is published by the repository owner, which is visible on every comment. If you want to disagree with one, the reply box works normally — that is the point.