Write an interface contract precisely
Specify an interface completely enough that both sides can build against it.
What this prompt helps you do
A contract with shapes, semantics, errors, idempotency, limits, and versioning.
When to use it
Two teams are building either side of an interface from a shared understanding that is not written down.
What to prepare
The goal, relevant source material, constraints, examples, and the decision or action this should support.
How to get a strong result
Specify the error cases and idempotency; those are what the two sides assume differently.
How to use this prompt
Replace each placeholder with accurate context. Paste the complete prompt into Claude, review the response critically, resolve important questions, and use it as a considered input to the next decision—not as an unchecked final answer.