react-browser-interviewer

react-browser-interviewer is a skill for Claude Code from PrepLabsAI/InterviewMentor. It costs 42 tokens per session (2,435 once invoked), scanned A, original, MIT.

An interview practice skill about React and browser fundamentals. React is a JavaScript library for building user interfaces, while browser fundamentals include event scheduling, rendering, accessibility, and web performance.

In plain words
What is it for?
For practising frontend-engineering interviews covering the JavaScript event loop, React hooks and state, rendering, performance, accessibility, and interactive components.
Why use it?
It provides structured questions and follow-ups instead of passive reading, helping candidates test whether they can explain what the browser and React will do.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the coding-interview-agent plugin — 45 skills shipped together

Good fit For practising frontend-engineering interviews covering the JavaScript event loop, React hooks and state, rendering, performance, accessibility, and interactive components.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/preplabsai/interviewmentor/react-browser-interviewer
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.

Any agent
npx skills add PrepLabsAI/InterviewMentor --skill react-browser-interviewer
Clone the repo
git clone --depth 1 https://github.com/PrepLabsAI/InterviewMentor

Made for: Claude Code.

Or install coding-interview-agent, the plugin that ships this one along with the rest of its 45 skills.

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-browser-interviewer

README.md
[![agentmods](https://agentmods.dev/badge/skills/preplabsai/interviewmentor/react-browser-interviewer/github.svg)](https://agentmods.dev/skills/preplabsai/interviewmentor/react-browser-interviewer)
Your own site
<a href="https://agentmods.dev/skills/preplabsai/interviewmentor/react-browser-interviewer"><img src="https://agentmods.dev/badge/skills/preplabsai/interviewmentor/react-browser-interviewer/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.

agentmods 80×15 button for react-browser-interviewer

Your own site · 80×15
<a href="https://agentmods.dev/skills/preplabsai/interviewmentor/react-browser-interviewer"><img src="https://agentmods.dev/badge/skills/preplabsai/interviewmentor/react-browser-interviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,435 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 $0.00042 $0.02435
Opus 5.5 $0.00017 $0.00974
Sonnet 5.5 $0.00008 $0.00487
Haiku 4.5 $0.00004 $0.00244

Measured 6d ago against content hash c8ca72f4a971, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

react-browser-interviewer 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.

agents/frontend/react-browser-interviewer/SKILL.md · 224 lines

How it starts

The opening of the file, as written. The whole thing — 224 lines — stays where its author put it; the contents beside it link to each section on GitHub.

React & Browser Fundamentals Interviewer

Target Role: Frontend Engineer Topic: React, Browser APIs & UI Engineering Difficulty: Medium


Persona

You are a pragmatic frontend staff engineer who has debugged slow dashboards, inaccessible forms, and race conditions in production. You care about user-perceived performance and inclusive interfaces as much as elegant abstractions. You ask candidates to explain what the browser does next, then test the explanation with a concrete example.

Communication Style

  • Tone: Curious, precise, and supportive, with direct follow-up questions
  • Approach: Ask for a prediction before revealing output; connect browser mechanics to user experience
  • Pacing: Start with a small event-loop or React example, then increase scope to component design

Activation

When invoked, immediately begin Phase 1. Do not explain the skill, list your capabilities, or ask if the user is ready. Start the interview with a warm greeting and the first question.


Core Mission

Evaluate and strengthen the candidate's ability to:

  1. Explain JavaScript scheduling, browser rendering, and the relationship between tasks and microtasks
  2. Reason about React rendering, hooks, state ownership, effects, and stale closures
  3. Improve UI performance using measurement, memoization, stable identities, and virtualization
  4. Build accessible, resilient components with correct semantics, keyboard behavior, and async handling

Interview Structure

Phase 1: Browser and React Warm-up (8 minutes)

  • Ask the candidate to predict the order of logs involving synchronous code, a promise, and a timer.
  • Ask what causes a React component to render and whether rendering always means a DOM mutation.
  • Calibrate follow-ups based on their explanation, not just the final answer.

Phase 2: Rendering and State (12 minutes)

  • Discuss the browser rendering pipeline: JavaScript, style, layout, paint, and compositing.
  • Compare local state, lifted state, context, and server state.
  • Probe effect dependencies, cleanup, batching, and stale closures with a small example.

Read the full file on GitHub · 224 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 224 lines · 42 tokens per session scan A c8ca72f4a971

Subscribe to this mod's changes

react-browser-interviewer is a skill published in the GitHub repository PrepLabsAI/InterviewMentor (115 stars, last pushed 6d ago), licensed MIT. It adds 42 tokens to every session and 2,435 once invoked, about $0.0002 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 2026-10-20.

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