Work out whether a change is backwards compatible
Examine a change against every consumer that depends on the current behaviour.
What this prompt helps you do
A compatibility verdict covering API shape, semantics, serialisation, and errors, with the breaks named.
When to use it
A change to a shared interface is planned and compatibility has been assumed.
What to prepare
The goal, relevant source material, constraints, examples, and the decision or action this should support.
How to get a strong result
Check semantic compatibility as well as structural; unchanged signatures with changed behaviour break consumers silently.
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.