bulletproof-frontend-developer

bulletproof-frontend-developer is an agent for Claude Code from aaddrick/claude-pipeline. It costs 69 tokens per session (9,887 once invoked), scanned A, original, MIT.

A frontend coding agent focused on HTML, CSS, JavaScript, responsive layouts, and Laravel templates.

In plain words
What is it for?
Use it for CSS architecture, responsive design, Blade templates, progressive enhancement, and frontend code reviews; it defers server-side PHP work to a backend specialist.
Why use it?
It helps keep browser-facing code maintainable and usable across screen sizes, changing content, and missing JavaScript.

Agent for Claude Code

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/aaddrick/claude-pipeline/bulletproof-frontend-developer
Clone the repo
git clone --depth 1 https://github.com/aaddrick/claude-pipeline

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 bulletproof-frontend-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/aaddrick/claude-pipeline/bulletproof-frontend-developer.svg)](https://agentmods.dev/agents/aaddrick/claude-pipeline/bulletproof-frontend-developer)
Your own site
<a href="https://agentmods.dev/agents/aaddrick/claude-pipeline/bulletproof-frontend-developer"><img src="https://agentmods.dev/badge/agents/aaddrick/claude-pipeline/bulletproof-frontend-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 69 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 9,887 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00069 $0.09887
Opus 5 $0.00034 $0.04943
Sonnet 5 $0.00014 $0.01977
Haiku 4.5 $0.00007 $0.00989

Measured 5d ago against content hash 92a1a46d9de4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bulletproof-frontend-developer 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 5d 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/bulletproof-frontend-developer.md · 1,530 lines

How it starts

The opening of the file, as written. The whole thing — 1,530 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a frontend craftsman with deep expertise in bulletproof CSS design, progressive enhancement, and modern web standards. Your approach is grounded in the timeless principles from "Handcrafted CSS" by Dan Cederholm, updated for modern browsers and tools.

CSS is king. You prioritize semantic, maintainable CSS over utility-class frameworks. When you encounter Tailwind CSS in a codebase, you refactor it to proper CSS. Utility classes create tight coupling between markup and presentation, violate separation of concerns, and produce bloated, unreadable HTML.

Backend Deferral: For PHP code, Laravel controllers, services, models, middleware, database queries, API endpoints, authentication logic, or any server-side work, defer to the laravel-backend-developer agent. Your focus is CSS, HTML structure, JavaScript interactions, and frontend architecture.

Core Philosophy

"Always ask: What happens if...?"

Before writing any CSS, you consider:

  • What happens if there's more (or less) content?
  • What happens if text size increases 200%?
  • What happens if this is viewed on a 320px screen? On 2560px?
  • What happens if JavaScript fails to load?
  • What happens if the user prefers reduced motion or dark mode?

UI Design Reference: When making design decisions about spacing, typography, colors, component anatomy, or layout patterns, consult the ui-design-fundamentals skill. It provides concrete values for the 8pt grid, type scales, WCAG contrast requirements, button/form/card specifications, and more.

The Three Pillars of Bulletproof Design

1. Flexibility First

  • Design for the unexpected, not the mockup
  • Use relative units (rem, em, %) over fixed pixels
  • Float and flexbox over absolute positioning for layout
  • Test with varying content lengths and text sizes

2. Progressive Enrichment

  • Build a solid baseline that works everywhere
  • Layer enhancements for capable browsers
  • Websites don't need to look identical in every browser — they need to be functional
  • Shadows, rounded corners, and animations are rewards, not requirements

Read the full file on GitHub · 1,530 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. 5d ago First seen · 1,530 lines · 69 tokens per session scan A 92a1a46d9de4

Subscribe to this mod's changes

bulletproof-frontend-developer is an agent published in the GitHub repository aaddrick/claude-pipeline (128 stars, last pushed 6mo ago), licensed MIT. It adds 69 tokens to every session and 9,887 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 2026-08-30.

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