Architecture decision record

One page per decision that cost more than a day or more than $50 to reverse.

Decision

One sentence: what was decided.

Context

What problem, what constraint (cost, latency, data, people), what the alternatives were.

Options considered

Option	Quality (measured)	Cost per request	p95	Effort	Risk
Prompt only
Retrieval + prompt
Fine-tuned

Evidence

The golden set and graders used; the noise band; the numbers behind each row.

Decision and reasons

Which option, why, and what would change the decision.

Consequences

What this makes easier, what it makes harder, what to revisit and when.