react-expert

react-expert is an agent for Claude Code from askjohngeorge/askjg-claude-agents. It costs 19 tokens per session (1,200 once invoked), scanned A, original, no licence file.

A coding guide for React, a JavaScript library for building user interfaces from reusable components. It covers hooks, application state, component structure, and performance.

In plain words
What is it for?
Use it to work with hooks, manage state, design component architectures, and improve React performance.
Why use it?
It helps you organize React code and troubleshoot how components share data or update on screen.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

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 agents/askjohngeorge/askjg-claude-agents/react-expert
Clone the repo
git clone --depth 1 https://github.com/askjohngeorge/askjg-claude-agents

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 react-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/askjohngeorge/askjg-claude-agents/react-expert.svg)](https://agentmods.dev/agents/askjohngeorge/askjg-claude-agents/react-expert)
Your own site
<a href="https://agentmods.dev/agents/askjohngeorge/askjg-claude-agents/react-expert"><img src="https://agentmods.dev/badge/agents/askjohngeorge/askjg-claude-agents/react-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,200 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00019 $0.01200
Opus 5 $0.00010 $0.00600
Sonnet 5 $0.00004 $0.00240
Haiku 4.5 $0.00002 $0.00120

Measured 6d ago against content hash 13911f1edd89, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

react-expert 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 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.

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/agents/react-expert.md · 153 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 153 lines · 19 tokens per session scan A 13911f1edd89

Subscribe to this mod's changes

react-expert is an agent published in the GitHub repository askjohngeorge/askjg-claude-agents (54 stars, last pushed 7mo ago), with no licence file. It adds 19 tokens to every session and 1,200 once invoked, about $0.0001 per session on Opus 5. 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 2026-08-30.

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