<objective Production is the richest source of test design input: every error log, slow trace, and latency spike tells you where tests are missing. This skill closes the feedback loop between production observability and test creation, and makes trace structure a test assertion. A that silently hit the database on a path meant to be cache-only passes an HTTP assertion — a trace assertion catches it. Output: instrumented test runners, trace-based assertions, and a production-error-to-test pipeline. </objective Quick Route | Situation | Go to | |-----------|-------| | Make test execution emit t…