An ADR has two failure modes at the structural level. The first is too short: it names the decision without naming the tradeoff or the context that made this tradeoff appropriate. This ADR is technically a record but not analytically useful — it tells you what was decided but not when you should revisit it. AT6 (Flexibility vs Simplicity) applies: a terse ADR is simple to write and read, but it creates future rigidity because the reasoning is invisible.
The second failure mode is too long: a document that rehearses every alternative in exhaustive detail and names so many tradeoffs that the decision disappears into hedging. This is the opposite failure — the reader cannot extract what was decided or why.
The correct structure names: what was decided, which tradeoff was accepted (using AT vocabulary), what condition would change this decision, and who made it and when. Four fields. The fourth field matters more than it appears — decisions without owners are not revisited.