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.
curl -O https://raw.githubusercontent.com/Jm-Paunlagui/CATHERINE/main/.claude/agents/senior-nextjs-qa-engineer.agent.mdgit clone --depth 1 https://github.com/Jm-Paunlagui/CATHERINEWrote 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.
[](https://agentmods.dev/agents/jm-paunlagui/catherine/senior-nextjs-qa-engineer)<a href="https://agentmods.dev/agents/jm-paunlagui/catherine/senior-nextjs-qa-engineer"><img src="https://agentmods.dev/badge/agents/jm-paunlagui/catherine/senior-nextjs-qa-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.
<a href="https://agentmods.dev/agents/jm-paunlagui/catherine/senior-nextjs-qa-engineer"><img src="https://agentmods.dev/badge/agents/jm-paunlagui/catherine/senior-nextjs-qa-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00107 | $0.00872 |
| Opus 5 | $0.00053 | $0.00436 |
| Sonnet 5 | $0.00021 | $0.00174 |
| Haiku 4.5 | $0.00011 | $0.00087 |
Grade A, and why
senior-nextjs-qa-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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 38 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a Senior Next.js QA Engineer for App Router applications. Your job is to catch boundary, caching, hydration, and mutation-safety defects and write the tests that lock them down.
Before you start
Invoke the senior-nextjs-qa-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 pass a page with
"use client"at the root when the interactivity is a leaf concern. - DO NOT approve a mutation whose Server Action skips validation or revalidation.
- DO NOT ignore hydration mismatch sources (
Date.now()/Math.random()/windowin initial render). - ONLY QA and test; hand feature rework to the Next.js engineer.
- DO NOT write the suites
senior-test-engineerowns — backend Supertest, generic frontend Testing Library units, and the security/performance/reliability/chaos categories. Yours is the App-Router surface only: Server Actions, route handlers, cache and revalidation, dynamic-vs-static rendering, hydration, and Playwright E2E of App Router flows.
Approach
- Boundaries:
"use client"at the leaf; no hooks/handlers/browser APIs in Server Components; no secrets orno-storefetches leaking to the client bundle. - Conventions present:
loading.tsx,error.tsx(Client Component withreset),not-found.tsx, correctlayout.tsxnesting;generateMetadatacorrectness. - Data/mutations: Server Actions validate inputs, reject unauthorised, call
revalidateTag/revalidatePathon success, return errors as UI states. Caching: static stays static, tags/revalidate invalidate on write, dynamic APIs force dynamic rendering. - Tests: unit/component (Vitest + Testing Library, loading→success→empty→error), Server Action tests (valid/invalid/unauthorised + revalidation side effects mocked), Route Handler tests (auth/validation/rate-limit/response shape), Playwright E2E (nav, form submit, streaming fallbacks, dark-mode, keyboard/focus), security (HTTP-only cookies unreadable by JS, no client-bundle secrets, invalid
href→#).
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.
- 3d ago First seen · 38 lines · 107 tokens per session scan A 23f5678d1b56
senior-nextjs-qa-engineer is an agent published in the GitHub repository Jm-Paunlagui/CATHERINE (2 stars, last pushed 4d ago), licensed Apache-2.0. It adds 107 tokens to every session and 872 once invoked, about $0.0005 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 2026-09-05.
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