A review of software performance, covering web applications and, when configured, native or backend programs. It checks code and configuration related to loading, data access, caching, images, memory, I/O, startup, and energy use.

Use it to inspect bundle size, lazy loading, caching, image handling, N+1 queries, and data fetching, or to combine those checks with profiling results.

It helps identify common causes of slow pages, heavy downloads, repeated database queries, inefficient data fetching, and unnecessary resource use.

perf-audit — Skill for Claude Code by marcoguillermaz

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add marcoguillermaz/Tierward --skill perf-audit

Clone the repo

git clone --depth 1 https://github.com/marcoguillermaz/Tierward

Made for: Claude Code.

Or install tierward, the plugin that ships this one along with the rest of its 29 skills, 1 command, 1 hook, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/marcoguillermaz/tierward/perf-audit/github.svg)](https://agentmods.dev/skills/marcoguillermaz/tierward/perf-audit)

Your own site

<a href="https://agentmods.dev/skills/marcoguillermaz/tierward/perf-audit"><img src="https://agentmods.dev/badge/skills/marcoguillermaz/tierward/perf-audit/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/marcoguillermaz/tierward/perf-audit"><img src="https://agentmods.dev/badge/skills/marcoguillermaz/tierward/perf-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,968 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00000	$0.03968
Opus 5	$0.00000	$0.01984
Sonnet 5	$0.00000	$0.00794
Haiku 4.5	$0.00000	$0.00397

Measured 10d ago against content hash 1c8bf3d073d3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

perf-audit scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/cli/templates/tier-l/.claude/skills/perf-audit/SKILL.md · 275 lines

How it starts

The opening of the file, as written. The whole thing — 275 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Configuration (adapt before first run)

Replace these placeholders:

[FRAMEWORK] - e.g. Next.js App Router, Remix, SvelteKit, plain React

[SITEMAP_OR_ROUTE_LIST] - e.g. docs/sitemap.md

[API_ROUTES_PATH] - e.g. routes/, src/handlers/, api/

[BUNDLE_TOOL] - e.g. @next/bundle-analyzer, vite-bundle-visualizer, webpack-bundle-analyzer

[PERF_TOOL] - profiling tool for native/backend stacks - e.g. Instruments (Swift), Android Profiler (Kotlin), perf / flamegraph (Rust/Go), cProfile (Python), dotnet-trace (.NET). If not configured, the skill runs static analysis only and recommends profiling setup.

[PROFILER_COMMAND] - command to generate a profile - e.g. xcrun xctrace record --template 'Time Profiler', go tool pprof, cargo flamegraph, python -m cProfile -o profile.out. If not configured, the skill skips the profiling step and proceeds with static analysis.

Note: if this is a public-facing app, remove the "Out of scope" restriction on Core Web Vitals

Applicability check

Before any other step: read CLAUDE.md and check the Framework and Language fields.

If the project is a web application (Framework is NOT N/A - native app and NOT N/A - no web frontend): proceed to Step 1 - Web Performance Audit (Steps 1–5).
If the project is a native or backend-only application (Framework is N/A - native app or N/A - no web frontend): skip Steps 1–5 and proceed directly to Step 6 - Native/Backend Performance Audit.

Context and scope

In scope: bundle composition, server/client component boundaries, dynamic rendering triggers, lazy loading, data fetching efficiency (caching, parallelism, N+1), re-render patterns, image optimization. For native stacks: algorithmic complexity, stack-specific hot-path patterns, memory management, launch weight, energy impact, binary size. Out of scope: SEO, CWV as ranking signals, robots.txt, sitemap.xml, OG tags, Lighthouse site audit, accessibility (→ /ui-audit), DB schema (→ /skill-db). Default mode: audit (report only, no code changes). mode:apply makes focused non-breaking fixes.

Read the full file on GitHub · 275 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

10d ago First seen · 275 lines · 0 tokens per session scan A 1c8bf3d073d3

Subscribe to this mod's changes

perf-audit is a skill published in the GitHub repository marcoguillermaz/Tierward (4 stars, last pushed 3d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 3,968 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Analytics and metrics Claude Code ai-assisted-development ai-governance cli developer-tools nodejs

harness-engineering

Use when the user asks to improve, fix, or build their repository's AI harness — AGENTS.md, rules, skills, commands, hooks, guardrails, CI sensors — or to act on harness-score audit findings and raise their maturity level.

paladini/harness-score · 55 tokens

codex-hud

Show Codex workspace context with local config, git state, hooks, and project hints. Standalone mode can show an expanded snapshot; patched Codex TUI footer mode is single-line. Use when the user says "codex-hud", "show Codex HUD", "status HUD", "workspace snapshot", or asks for richer Codex context.

brandonwie/codex-hud · 76 tokens

perf-audit