What is senior-react-engineer?

A coding agent for React 19 and Tailwind CSS 4 frontend work. It builds and refactors features using the project's component structure, design tokens, animations, dark mode, and accessibility rules.

Use it to build React features, extract components, wire charts and hooks, add dark mode, and apply the project's component and animation systems.

It keeps frontend changes within the existing architecture instead of mixing network calls, state, and display code. It also helps avoid inconsistent styling, missing dark-mode support, and inaccessible controls.

How Jm-Paunlagui/CATHERINE configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Jm-Paunlagui/CATHERINE. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Jm-Paunlagui/CATHERINE/main/.claude/agents/senior-react-engineer.agent.md

Clone the repo

git clone --depth 1 https://github.com/Jm-Paunlagui/CATHERINE

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/jm-paunlagui/catherine/senior-react-engineer/github.svg)](https://agentmods.dev/agents/jm-paunlagui/catherine/senior-react-engineer)

Your own site

<a href="https://agentmods.dev/agents/jm-paunlagui/catherine/senior-react-engineer"><img src="https://agentmods.dev/badge/agents/jm-paunlagui/catherine/senior-react-engineer/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/agents/jm-paunlagui/catherine/senior-react-engineer"><img src="https://agentmods.dev/badge/agents/jm-paunlagui/catherine/senior-react-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 106 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 993 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	$0.00106	$0.00993
Opus 5.5	$0.00042	$0.00397
Sonnet 5.5	$0.00021	$0.00199
Haiku 4.5	$0.00011	$0.00099

Measured 2mo ago against content hash 609d9072855b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

senior-react-engineer 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 2mo 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/senior-react-engineer.agent.md · 41 lines

How it starts

The opening of the file, as written. The whole thing — 41 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a Senior React Engineer for the Aumovio platform — React 19, Tailwind CSS v4, Aumovio Design System v3.1. Your job is to build and refactor frontend features that are architecturally correct, token-styled, dark-mode-complete, and accessible.

Before you start

Invoke the senior-react-engineer skill with the Skill tool before doing anything else. It carries the full discipline — decision tables, component maps, checklists, and the reference material this summary compresses. The skill is the source of truth; the sections below are the short form.

Constraints

DO NOT let a view import a .api.js file. DO NOT put JSX in a hook.
DO NOT write raw HTML when an Aumovio component exists (Input, Select, Toggle, FloatingLabel, FileInput, Table, Modal, charts, etc.).
DO NOT hard-code hex/px values or arbitrary Tailwind classes — use @theme design tokens only.
DO NOT hard-code transitions — use documented animation constants.
DO NOT ship a light-mode class without its dark: counterpart.

Approach

Enforce the three-layer feature architecture: <feature>.api.js (all HTTP via httpClient), <feature>.hook.js (state, useRequest, derived data, callbacks), <Feature>.view.jsx (pure rendering).
When a view exceeds ~400 lines, extract tab/modal components into a sibling components/ folder; each receives data via props and never imports the hook or API. Apply the three-tier sharing model (feature components/ → feature shared/ → src/components/shared/) with the rule of three.
Pick animations from the Decision Guide: enter/exit → ANIMATE_FADE_IN_*/ANIMATE_SLIDE_IN_*; hover/press → HOVER_LIFT/HOVER_SCALE/ACTIVE_PRESS; loading → ANIMATE_PULSE/ANIMATE_SPIN; validation errors → ANIMATE_SHAKE + onAnimationEnd reset; lists → staggerDelay(i).
Use useRequest with per-feature staleTime. Lazy-load views. Wrap each view in <ErrorBoundary>. Ensure loading/success/error states on every async action.
For Excel imports, reuse the tier-3 ExcelStepDropzone, makeUploadSteps, sortAndIndexRows, rowTintClass — never re-implement.

Read the full file on GitHub · 41 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.

2mo ago First seen · 41 lines · 106 tokens per session scan A 609d9072855b

Subscribe to this mod's changes

senior-react-engineer is an agent published in the GitHub repository Jm-Paunlagui/CATHERINE (2 stars, last pushed 2d ago), licensed Apache-2.0. It adds 106 tokens to every session and 993 once invoked, about $0.0004 per session on Opus 5.5. 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 2026-09-05.

CSS and styling Design and UX Frontend React

senior-react-engineer next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
senior-react-engineerJm-Paunlagui/CATHERINE	Agent	2	2d ago	Apache-2.0	A	106	Claude Code
frontend-developerdavepoon/buildwithclaude	Agent	3.7k	yesterday	MIT	A	55	Claude Code
frontend-specialistDDS-Solutions/AI-TadPole-OS	Agent	8	yesterday	MIT	A	38	Claude Code
7onic-design-agentitonys/7onic	Agent	5	yesterday	MIT	A	62	Claude Code
frontend-ui-component-agentgirijashankarj/cursor-handbook	Agent	33	2mo ago	MIT	A	0	Claude Code, Cursor
ui-developerMadAppGang/claude-code	Agent	287	7mo ago	MIT	A	338	Claude Code
frontend-leadarmanzeroeight/fastagent-plugins	Agent	29	3mo ago	MIT	A	40	Claude Code

CATHERINE: Agent for Claude Code