perf-compare: one way to measure performance

Every agent that tunes speed or stability measures with this recipe, so results are comparable across agents and noise is not reported as a win. Sentry is the store: org significant-gravitas, API https://us.sentry.io, tracing at 100%. scripts/perf_compare.py (Python 3.8+, standard library only) runs the queries and the statistics.

S=$(git rev-parse --show-toplevel)/.claude/skills/perf-compare/scripts/perf_compare.py
python3 "$S" --help

When to use it

• Before claiming a change made something faster or slower, on a preview or after merge.
• After merge, to check a win holds on dev and then prod (release against release).
• To check a change did not regress other transactions (run without --transaction).
• For any numeric field: span.duration (default), web vitals on builder pageloads (measurements.lcp), LLM token counts (gen_ai.usage.input_tokens), or custom attributes (tags[name,number]).

It is not for debugging one slow request (open the trace) or for error triage.

Token