Case Studies

Case: all failures became empty history

A client catches every exception and returns count 0. A service outage now looks like successful empty data. Repair by preserving failure status and reporting the boundary; add both valid-empty and unavailable fixtures so they cannot collapse into one behavior.

Case: a format changed under the consumer

The server replaces integer durations with named records. The old client rejects the new shape. The rejection is useful evidence of an incompatible boundary, not a reason to disable validation. Define the variant, update both sides deliberately and retain compatibility tests as required by the chosen policy.