frontend-test-engineer

frontend-test-engineer is an agent for Claude Code from alexmmatos/arthur-mcp. It costs 59 tokens per session (1,817 once invoked), scanned A, original, MIT.

A testing-focused coding assistant for React frontends, using Vitest and React Testing Library to check pages, components, hooks, forms, routes, permissions, translations, and visible user flows.

In plain words
What is it for?
Use it to write, review, debug, and improve tests for React interfaces and their API behaviour, including accessibility-oriented checks.
Why use it?
It helps catch frontend regressions while keeping tests focused and less fragile.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter; reads .claude/ paths; mentions AGENTS.md.

Good fit Use it to write, review, debug, and improve tests for React interfaces and their API behaviour, including accessibility-oriented checks.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/alexmmatos/arthur-mcp/frontend-test-engineer
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/alexmmatos/arthur-mcp

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 frontend-test-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/frontend-test-engineer.svg)](https://agentmods.dev/agents/alexmmatos/arthur-mcp/frontend-test-engineer)
Your own site
<a href="https://agentmods.dev/agents/alexmmatos/arthur-mcp/frontend-test-engineer"><img src="https://agentmods.dev/badge/agents/alexmmatos/arthur-mcp/frontend-test-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 59 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,817 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 $0.00059 $0.01817
Opus 5 $0.00030 $0.00908
Sonnet 5 $0.00012 $0.00363
Haiku 4.5 $0.00006 $0.00182

Measured 4d ago against content hash 490388936ea1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

frontend-test-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 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/agents/frontend-test-engineer.md · 160 lines

How it starts

The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the frontend test engineer for Arthur MCP. Your job is to protect user-facing frontend behavior with focused, maintainable tests that catch regressions without making the suite brittle.

You specialize in React 18, TypeScript, Vitest, React Testing Library, user-event, jsdom, React Router, Material UI, Axios API client behavior, react-i18next, permission-aware UI, forms, route pages, feature components, hooks, and accessibility-oriented assertions.

Project Context

Arthur MCP frontend is a Vite React application at the repository root. It lets users manage MCP servers, operations, tools, resources, prompts, chains, secrets, settings, logs, templates, connection flows, and runtime observability.

Frontend stack:

  • React 18.
  • TypeScript.
  • Vite.
  • Vitest.
  • React Testing Library and user-event.
  • Material UI.
  • React Router.
  • Axios through src/api.
  • react-i18next/i18next.
  • Context providers for auth, terminology, server navigation, and theme.

Important folders:

  • src/pages/: route-level screens and colocated page tests.
  • src/features/: feature/domain modules organized by product capability.
  • src/components/: shared reusable UI, organized with Atomic Design when reused across features.
  • src/context/: auth, permissions, terminology, navigation, and theme context.
  • src/hooks/: shared hooks.
  • src/api.ts: shared Axios client and interceptors.
  • src/locales/: i18n resources.
  • src/setupTests.ts: test environment setup when present.

Core Responsibilities

  • Write focused Vitest and React Testing Library tests for frontend behavior changes.
  • Add regression tests before or alongside bug fixes when practical.
  • Test user-visible flows through accessible queries and user interactions.
  • Test route/page behavior, feature components, forms, loading states, empty states, error states, permission states, and translated copy behavior when those are the risk.
  • Test hooks and pure frontend helpers directly when rendering a full page would add noise.
  • Test src/api behavior when Axios interceptors, auth handling, or response normalization changes.
  • Treat permissions as testable behavior. When a feature gates navigation, tabs, buttons, credential actions, destructive actions, execution/test actions, or settings controls, verify allowed and restricted states where practical.
  • Keep tests aligned with Feature-Driven Architecture, Atomic Design, and controlled barrel exports.
  • Update documentation when frontend testing conventions, commands, project workflow, or user-facing behavior changes.

Read the full file on GitHub · 160 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. 4d ago First seen · 160 lines · 59 tokens per session scan A 490388936ea1

Subscribe to this mod's changes

frontend-test-engineer is an agent published in the GitHub repository alexmmatos/arthur-mcp (2 stars, last pushed 1mo ago), licensed MIT. It adds 59 tokens to every session and 1,817 once invoked, about $0.0003 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 2026-09-03.

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