crxjs

crxjs is a skill for Claude Code from samber/cc-skills. It costs 186 tokens per session (2,698 once invoked), scanned A, original, MIT.

A Vite-based development tool for building Chrome extensions from a manifest, the file that describes an extension's parts and permissions.

In plain words
What is it for?
Developing extension popups, settings pages, content scripts, side panels, and service workers.
Why use it?
It updates extension components while you work and handles the builds and browser injection steps needed for development.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions Claude Code; mentions Codex; built for openclaw.

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is cd dist && zip -r ../extension.zip ..

Part of the cc-skills plugin — 21 skills shipped together

not rated 207repo +6 2d ago A scan Socket: passSnyk: passSkillSpector: pass 186 tokens original MIT

Good fit Developing extension popups, settings pages, content scripts, side panels, and service workers.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/samber/cc-skills
agentmods
npx agentmods add skills/samber/cc-skills/crxjs

Made for: Claude Code.

Or install cc-skills, the plugin that ships this one along with the rest of its 21 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 crxjs

README.md
[![agentmods](https://agentmods.dev/badge/skills/samber/cc-skills/crxjs/github.svg)](https://agentmods.dev/skills/samber/cc-skills/crxjs)
Your own site
<a href="https://agentmods.dev/skills/samber/cc-skills/crxjs"><img src="https://agentmods.dev/badge/skills/samber/cc-skills/crxjs/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 crxjs

Your own site · 80×15
<a href="https://agentmods.dev/skills/samber/cc-skills/crxjs"><img src="https://agentmods.dev/badge/skills/samber/cc-skills/crxjs.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 186 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,698 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. Third-party audits
  • Socket pass 11 Apr 2026
  • Snyk pass 11 Apr 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00186 $0.02698
Opus 5 $0.00093 $0.01349
Sonnet 5 $0.00037 $0.00540
Haiku 4.5 $0.00019 $0.00270

Measured 9d ago against content hash 0c55dd601dbe, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

crxjs 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 9d 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

  • crxjs — 94% identical, 5 lines differ
  • crxjs — 94% identical, 4 lines differ
skills/crxjs/SKILL.md · 338 lines

How it starts

The opening of the file, as written. The whole thing — 338 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CRXJS

CRXJS is a Chrome extension development tool that provides true HMR for popup, options, content scripts, and side panels. It reads your manifest to auto-generate the extension output, handles content script injection, and manages the service worker build. Under the hood it is a Vite plugin (@crxjs/vite-plugin).

Current status

  • Package: @crxjs/vite-plugin (v2.x stable, latest v2.4.0 as of March 2026)
  • Scaffolding: npm create crxjs@latest (always use @latest)
  • Maintained by: @Toumash and @FliPPeDround (since mid-2025)
  • GitHub: github.com/crxjs/chrome-extension-tools (~4k stars)
  • Vite compatibility: v3 through v8-beta

Quick start

# Scaffold new project (picks framework interactively)
npm create crxjs@latest

# Or add to existing Vite project
npm install @crxjs/vite-plugin -D

Vite config by framework

CRXJS is added as a Vite plugin. The setup varies slightly per framework.

React

// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { crx } from "@crxjs/vite-plugin";
import manifest from "./manifest.json";

export default defineConfig({
  plugins: [react(), crx({ manifest })],
});

Use @vitejs/plugin-react (not plugin-react-swc) for best HMR compatibility. If you must use SWC, cast the manifest:

import { ManifestV3Export } from "@crxjs/vite-plugin";
const manifest = manifestJson as ManifestV3Export;

Vue

import vue from "@vitejs/plugin-vue";
import { crx } from "@crxjs/vite-plugin";
import manifest from "./manifest.json";

export default defineConfig({
  plugins: [vue(), crx({ manifest })],
});

Svelte

import { svelte } from "@sveltejs/vite-plugin-svelte";
import { crx } from "@crxjs/vite-plugin";
import manifest from "./manifest.json";

export default defineConfig({
  plugins: [svelte(), crx({ manifest })],
});

Vanilla TypeScript

import { crx } from "@crxjs/vite-plugin";
import manifest from "./manifest.json";

export default defineConfig({
  plugins: [crx({ manifest })],
});

Read the full file on GitHub · 338 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. 9d ago First seen · 338 lines · 186 tokens per session scan A 0c55dd601dbe

Subscribe to this mod's changes

crxjs is a skill published in the GitHub repository samber/cc-skills (207 stars, last pushed 2d ago), licensed MIT. It adds 186 tokens to every session and 2,698 once invoked, about $0.0009 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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