Benchmark Regression Triage

Overview

This skill diagnoses VibeGuard hook latency regressions by comparing GitHub Actions bench-output artifacts across PR runs, merge runs, and mainline runs. It is meant for non-obvious cases where the current benchmark is under budget but slower than a previous design, such as a post-write-guard path losing its post-write-fast-check fast path after a runtime migration.

Treat CI artifacts as the trend source. Local benchmarks are useful for reproduction after a hypothesis exists, but they are not comparable to GitHub runner history because machine load, shell startup, cache state, and --runs count can dominate P95.

When to Activate

• A user asks why VibeGuard benchmark numbers are slower than before.
• A PR appears to change hook latency, benchmark output, or benchmark-action reporting.
• You need to compare recent PRs with older anchors such as PR #350 or a known fast-path implementation.
• A hook is still below the absolute latency budget but may have lost a faster design.
• You need a reusable workflow for downloading and comparing GitHub Actions bench-output artifacts.

Inputs

Collect these before drawing conclusions: