dev-react-perf

dev-react-perf is a command for Claude Code from christopherlouet/claude-base. It costs 0 tokens per session (358 once invoked), scanned A, original, MIT.

A performance audit and optimization guide for React and Next.js applications. React is a user-interface library, while Next.js is a framework built around it.

In plain words
What is it for?
Use it to review metrics such as LCP and bundle size, find performance issues, apply fixes, and compare results before and after.
Why use it?
It helps identify slow page loads, oversized JavaScript bundles, unnecessary re-renders, and inefficient data loading in priority order.

Command for Claude Code

Written for Claude Code: $ARGUMENTS substitution.

Good fit Use it to review metrics such as LCP and bundle size, find performance issues, apply fixes, and compare results before and after.

Compare 6 commands from other repositories ↓
Install with agentmods
npx agentmods add commands/christopherlouet/claude-base/dev-react-perf
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.

Clone the repo
git clone --depth 1 https://github.com/christopherlouet/claude-base

Made for: Claude Code.

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 dev-react-perf

README.md
[![agentmods](https://agentmods.dev/badge/commands/christopherlouet/claude-base/dev-react-perf.svg)](https://agentmods.dev/commands/christopherlouet/claude-base/dev-react-perf)
Your own site
<a href="https://agentmods.dev/commands/christopherlouet/claude-base/dev-react-perf"><img src="https://agentmods.dev/badge/commands/christopherlouet/claude-base/dev-react-perf.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 358 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00000 $0.00358
Opus 5 $0.00000 $0.00179
Sonnet 5 $0.00000 $0.00072
Haiku 4.5 $0.00000 $0.00036

Measured 4d ago against content hash 2baef1f85485, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

dev-react-perf 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 4d 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.

.claude/commands/dev/dev-react-perf.md · 47 lines

What it actually says

DEV-REACT-PERF Agent

React/Next.js performance optimization based on rules prioritized by impact.

Request context

$ARGUMENTS

Goal

Audit and optimize React/Next.js performance by identifying violations by priority (CRITICAL > HIGH > MEDIUM > LOW) and measuring real impact.

Workflow

  • Analyze current metrics (LCP, bundle size, re-renders)
  • Identify CRITICAL violations: waterfalls (async parallel, defer await, suspense boundaries)
  • Identify CRITICAL violations: bundle size (barrel imports, dynamic imports, preload)
  • Identify HIGH violations: server cache (React cache, LRU), client fetching (SWR/React Query)
  • Identify MEDIUM violations: re-renders (memo, dependencies, transitions), rendering (content-visibility, hydration)
  • Identify LOW violations: JS micro-optimizations, advanced patterns
  • Measure BEFORE and AFTER each optimization
  • Produce a report with violations, corrections and estimated gains

Expected output

Optimization report with current score, violations by priority (file + estimated impact), proposed corrections and measured gains (LCP, bundle size).

Agent When to use it
/qa:qa-perf Generic performance audit (not React-specific)
/dev:dev-refactor After identifying optimizations
/dev:dev-component Create optimized components from the start
/qa:qa-review Review including performance

IMPORTANT: Measure BEFORE and AFTER each optimization to validate real impact.

YOU MUST prioritize CRITICAL > HIGH > MEDIUM > LOW.

NEVER optimize prematurely - profile first, optimize later.

Think hard about the effort/gain ratio of each optimization.

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. 4d ago First seen · 47 lines · 0 tokens per session scan A 2baef1f85485

Subscribe to this mod's changes

dev-react-perf is a command published in the GitHub repository christopherlouet/claude-base (5 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 358 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 2026-09-03.