App performance testing

Measure single-user endpoint speed, find the layer the time goes to, and rank fixes. The default is one request at a time after warm-up, not load. Everything is evidence-led: each conclusion is labelled measured (with the evidence) or inferred from code, never one passed off as the other.

Grafana work is delegated to the Grafana skills when installed (promql, loki, tempo, k6, pyroscope, performance-rca). Load the one for the query language you are about to write instead of guessing syntax.

Per-repo files

The skill is generic; each app keeps its own facts under <repo>/.claude/perf/: