ln-31-performance-optimizer

# Performance Optimizer **Goal:** Optimize only measured problems. Preserve correctness, isolate experiments, and retain a change only when comparable evidence shows that it improves the agreed metric without unacceptable regressions. **Execution contract:** Treat the ordered checkbox workflow below as this skill's Definition of Done. Work through every item in order, and mark it complete only when its action and required evidence are complete. `N/A`, skipped, unavailable, or delegated items remain incomplete. Before returning, apply this skill's verdict, decision, and approval rules to every incomplete item and prepend **Checklist: X/Y complete**<br>**Incomplete: None | section/item — reason; outcome impact; exact next action**; list every incomplete item. ## Tool Routing | Need | Preferred tool | Use it when | Fallback | |---|---|---|---| | Repository state and safe edit boundary | Git status, diff, branch or worktree inspection, and repository instructions | Always before profiling or editing | Stop if user changes cannot be isolated safely | | Baseline and final metric | Existing benchmark, load test, reproducible command, or production-like replay | The metric and workload reflect the reported problem | Create the smallest local benchmark that reproduces the behavior without inventing production scale | | Bottleneck evidence | Existing profiler, tracing, query diagnostics, allocation tools, or OS-level metrics | Locating CPU, memory, I/O, lock, query, network, or sch...