hm-performance

hm-performance is a skill for Claude Code, Codex from rodrigohighermind/highermind-code-skills. It costs 118 tokens per session (2,223 once invoked), scanned A, original, MIT.

A guide for measuring where an application is slow and setting concrete performance targets. It covers areas such as JavaScript and CSS size, page-loading measures, and other performance limits described by the skill.

In plain words
What is it for?
Use it before releasing speed-sensitive features such as chat, large lists, or dashboards; after data-flow refactors; during regular checks of growing projects; or when API response time and cost need investigation.
Why use it?
It replaces guesses about slowness with measurements that show which part needs fixing. This helps when users report delays, a data-flow change may have slowed the app, or language-model and API costs rise.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

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.

agentmods
npx agentmods add skills/rodrigohighermind/highermind-code-skills/hm-performance
Any agent
npx skills add rodrigohighermind/highermind-code-skills --skill hm-performance
Clone the repo
git clone --depth 1 https://github.com/rodrigohighermind/highermind-code-skills

Made for: Claude Code, Codex.

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.

agentmods badge for hm-performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/rodrigohighermind/highermind-code-skills/hm-performance.svg)](https://agentmods.dev/skills/rodrigohighermind/highermind-code-skills/hm-performance)
Your own site
<a href="https://agentmods.dev/skills/rodrigohighermind/highermind-code-skills/hm-performance"><img src="https://agentmods.dev/badge/skills/rodrigohighermind/highermind-code-skills/hm-performance.svg" alt="Measured on agentmods" height="20"></a>
Per session 118 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,223 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00118 $0.02223
Opus 5 $0.00059 $0.01111
Sonnet 5 $0.00024 $0.00445
Haiku 4.5 $0.00012 $0.00222

Measured 6d ago against content hash a8b4495a8450, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

hm-performance scanned grade A with 1 finding 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 6d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- `time` no curl pra teste manual
hm-performance/SKILL.md · 235 lines

How it starts

The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/hm-performance — Performance Profiling (v1)

Você está agora em modo performance. Seu trabalho e medir e localizar gargalos. Não especular. Não adivinhar. Números concretos, com fix especifico pra cada métrica fora do alvo.

Princípio central

Performance não é uma feature. E uma restrição de design. App lento é bug. Latencia alta no LLM e custo alto disfarcado. Bundle inflado e tempo de carga perdido. Cada milissegundo importa porque o usuario sente, mesmo que não consiga nomear.

Quando usar

  • Antes de shippar feature nova com componente performance-critical (chat, lista grande, dashboard com muitos widgets)
  • Quando user reclama "ta lento"
  • Apos refactor que mexeu em data flow
  • Periodicamente em projetos com escala (semanal/mensal)
  • Quando custo de LLM/API explode

Dominios

1. Frontend — Bundle size

Métrica Alvo CRÍTICO se
First-load JS (Next.js) <200KB gzipped >400KB
Per-route JS <100KB gzipped >200KB
Total JS no app <500KB gzipped >1MB
CSS <50KB gzipped >100KB
Image assets primeira tela <200KB total >500KB

Como medir:

# Next.js
bun run build  # mostra tamanho por rota
# ou
ANALYZE=true bun run build  # com @next/bundle-analyzer

# Vite
bun run build  # mostra warnings pra chunks >500KB

# Generic
du -sh .next/static/chunks/*.js | sort -h | tail

Anti-patterns:

  • Importar lib inteira: import _ from 'lodash' (use lodash-es named imports)
  • Moment.js (use date-fns ou Intl nativo)
  • Lib de charts pesada quando precisa de 1 chart simples (recharts vs chart.js vs SVG manual)
  • React component lib gigante usada pra 3 componentes (avalia composicao manual)

2. Frontend — Render performance

Métrica Alvo
LCP (Largest Contentful Paint) <2.5s
FID/INP (Interaction to Next Paint) <200ms
CLS (Cumulative Layout Shift) <0.1
TTFB (Time to First Byte) <600ms
Re-renders desnecessarios Minimizado via memo/useMemo

Como medir:

  • DevTools → Lighthouse (audit local)
  • web-vitals package + analytics
  • React DevTools Profiler pra re-renders

Read the full file on GitHub · 235 lines

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.

  1. 6d ago First seen · 235 lines · 118 tokens per session scan A a8b4495a8450

Subscribe to this mod's changes

hm-performance is a skill published in the GitHub repository rodrigohighermind/highermind-code-skills (192 stars, last pushed 2mo ago), licensed MIT. It adds 118 tokens to every session and 2,223 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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