perf-audit

name	perf-audit
description	Finds performance bottlenecks in code - N+1 queries, unnecessary re-renders, blocking operations
argument-hint	["file-or-directory"]
user-invocable	true
allowed-tools	Read Grep Glob
effort	medium

Performance Audit

Target: $1 (or src/ if not specified)

Database / API

• N+1 query patterns (loop with query inside)
• Missing indexes (queries on non-indexed columns)
• Fetching all fields when only a few are needed (SELECT *)
• Sequential async calls that could be parallel (Promise.all)

Frontend

• Expensive computations on every render (should use useMemo)
• Event listeners added without cleanup
• Large imports not code-split (import * from)
• Images without lazy loading or size hints

General

• Synchronous operations that block the event loop
• Memory leaks (closures holding references)
• Redundant data transformation loops (can be combined)
• Missing caching for expensive operations

---

For each finding:

1. Show the problematic code
2. Explain the performance impact
3. Show the fix
4. Estimate improvement (rough order of magnitude)

Prioritize by impact: fix things that run in hot paths (request handlers, render functions, loops) first.