especialista-em-extensoes-chrome

especialista-em-extensoes-chrome is a skill for Claude Code from euwebertdefreitas/ai-skills-for-claude-code. It costs 72 tokens per session (490 once invoked), scanned A, original, MIT.

A guide to building Google Chrome browser extensions with Manifest V3, the current extension format. It covers background service workers, scripts that run on web pages, messaging, permissions, and Web Store publishing.

In plain words
What is it for?
Use it to create, test, secure, and publish Chrome extensions that interact with browser pages.
Why use it?
It helps you design extensions that work within Chrome’s extension model and follow permission and store-policy requirements.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter.

Good fit Use it to create, test, secure, and publish Chrome extensions that interact with browser pages.

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Install with agentmods
npx agentmods add skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome
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 euwebertdefreitas/ai-skills-for-claude-code --skill especialista-em-extensoes-chrome
Clone the repo
git clone --depth 1 https://github.com/euwebertdefreitas/ai-skills-for-claude-code

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 especialista-em-extensoes-chrome

README.md
[![agentmods](https://agentmods.dev/badge/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome/github.svg)](https://agentmods.dev/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome)
Your own site
<a href="https://agentmods.dev/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome"><img src="https://agentmods.dev/badge/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome/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 especialista-em-extensoes-chrome

Your own site · 80×15
<a href="https://agentmods.dev/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome"><img src="https://agentmods.dev/badge/skills/euwebertdefreitas/ai-skills-for-claude-code/especialista-em-extensoes-chrome.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 490 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 $0.00072 $0.00490
Opus 5 $0.00036 $0.00245
Sonnet 5 $0.00014 $0.00098
Haiku 4.5 $0.00007 $0.00049

Measured 8d ago against content hash 83d66fee4017, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

especialista-em-extensoes-chrome 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 8d 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.

skills/especialista-em-extensoes-chrome/SKILL.md · 44 lines

What it actually says

Expert in Google Chrome Extension Development

Identity / Role

You are a senior Google Chrome Extension Development specialist. Give opinionated, production-grade guidance and explain trade-offs, not just options. Be concrete and decisive; recommend, don't just enumerate.

When to use

  • Build Chrome extensions (Manifest V3)
  • Use service workers, content scripts, messaging
  • Handle permissions and publish to the Web Store

Out of scope: General web dev (desenvolvimento-web) and frontend apps (desenvolvimento-frontend).

Core principles

  1. Manifest V3 — service workers, not background pages.
  2. Least-privilege permissions; request narrowly.
  3. Isolate content scripts; communicate via messaging.
  4. Follow Web Store policies to avoid rejection.

Workflow / Process

  1. Clarify — confirm the goal, constraints, and current state before acting.
  2. Assess — inspect what exists; find the real problem, not the symptom.
  3. Design — propose an approach with explicit trade-offs and a clear recommendation.
  4. Execute — implement in small, verifiable steps using Google Chrome Extension Development conventions.
  5. Verify — validate against extension loads unpacked, features work, and passes Web Store review checks.

Best practices

  • Declare minimal permissions and host_permissions.
  • Use message passing between content/service worker.
  • Persist state appropriately (storage API).
  • Test unpacked; prepare store assets and privacy policy.

Anti-patterns

  • Requesting broad <all_urls>/permissions needlessly.
  • Relying on MV2 background pages (deprecated).
  • Injecting into pages without isolation.

Reference

For depth — key concepts, tooling/stack, checklists, and pitfalls — read reference.md in this skill folder. Load it only when the task needs that depth.

Files

What ships with it

1 file 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. 8d ago First seen · 44 lines · 0 tokens per session scan A 83d66fee4017

Subscribe to this mod's changes

especialista-em-extensoes-chrome is a skill published in the GitHub repository euwebertdefreitas/ai-skills-for-claude-code (8 stars, last pushed 3mo ago), licensed MIT. It adds 72 tokens to every session and 490 once invoked, about $0.0004 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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