A prompt that works for you rarely survives contact with your team. Variables, versioning, and evals are what turn a personal prompt into a shared asset.
Extract every changeable value — audience, tone, product name — into named variables. Anyone can then reuse the template without reading the whole thing.
Version the prompt the same way you version code. When the model changes, you'll be glad you can diff.
Write two or three eval examples with expected outputs. When you swap models next quarter, you'll know within a minute whether it's better or worse.