The department's job isn't "building" in the abstract — it's shipping one verified increment at a time, each one small enough to describe honestly in a paragraph. A pull request that says exactly what changed, why, and how it was verified is worth more than a changelog full of vague adjectives.
The shape: what changed (one sentence), why (one sentence), how you verified it (the specific check, not "tested it"), what's explicitly not covered by this increment. That's a shippable unit — small, honest, checkable by someone who wasn't there.
Take the spec, the increments, and the verification from the last three lessons and compress them into that exact shape — one shippable increment description, ready to hand off.