codeprobe-performance

Standalone Mode

If invoked directly (not via the orchestrator), you must first:

1. Read ../codeprobe/shared-preamble.md (resolve relative to this SKILL.md's location — the sibling codeprobe skill directory — not the user's project) for the output contract, execution modes, and constraints.
2. Load applicable reference files from ../codeprobe/references/ (same resolution) based on the project's tech stack.
3. Default to full mode unless the user specifies otherwise.

Performance & Scalability Auditor

Domain Scope

This sub-skill detects performance and scalability issues across these categories:

1. N+1 Queries — Lazy-loading relationships inside loops
2. Missing Indexes — WHERE/ORDER BY on non-indexed columns
3. Unbounded Queries — Model::all() without pagination/limit
4. Memory — Loading entire files into memory, array accumulation in loops
5. Caching — Repeated identical queries, missing TTL, stale cache after writes
6. Algorithmic Efficiency — O(n^2) in hot paths, nested loops, sorting in loops
7. Concurrency — Race conditions, non-idempotent queue jobs, shared mutable state
8. Frontend Performance — Unnecessary re-renders, bundle size, missing lazy loading

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What It Does NOT Flag

• Premature optimization in non-hot-path code — proportional design matters. A utility function called once at startup doesn't need the same optimization as a request handler.
• Development-only debug queries — queries in seeders, dev-only commands, or debug endpoints.
• Batch processing scripts — scripts intentionally designed to process everything (migrations, data backfills) where unbounded queries may be appropriate.
• O(n^2) on small bounded collections (<100 items) — nested loops on small known-size arrays are fine.
• Frontend SSR/build-time code — server components and build scripts have different performance profiles than client-side code.

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Detection Instructions

N+1 Queries

ID Prefix	What to Detect	How to Detect	Severity
PERF	Eloquent relationship access inside loop without eager loading	Search for foreach/for loops iterating over a collection, then accessing a relationship property (e.g., $order->items, $user->profile) inside the loop body. Check whether the query that produced the collection includes with() or load() for that relationship.	Major
PERF	Any ORM lazy-loading inside iteration	Look for patterns where a database query is implicitly triggered inside a loop: Django querysets accessed per-iteration, SQLAlchemy lazy loads, Prisma relation access in .map().	Major
PERF	Template/view triggering queries	Blade templates, Jinja2 templates, or React components calling relationship properties that trigger queries during rendering.	Major