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.
npx skills add quangpl/browser-extension-skills --skill extension-devgit clone --depth 1 https://github.com/quangpl/browser-extension-skillsWrote 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/skills/quangpl/browser-extension-skills/extension-dev)<a href="https://agentmods.dev/skills/quangpl/browser-extension-skills/extension-dev"><img src="https://agentmods.dev/badge/skills/quangpl/browser-extension-skills/extension-dev/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/skills/quangpl/browser-extension-skills/extension-dev"><img src="https://agentmods.dev/badge/skills/quangpl/browser-extension-skills/extension-dev.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 | $0.00030 | $0.01599 |
| Opus 5.5 | $0.00012 | $0.00640 |
| Sonnet 5.5 | $0.00006 | $0.00320 |
| Haiku 4.5 | $0.00003 | $0.00160 |
Grade A, and why
extension-dev 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 1mo 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 — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Extension Dev
🚀 Upgrade to Premium Get the Premium version at https://app.extensionbooster.net/dashboard/services/extension-ai-kit
Detect the stack, find docs, implement the feature, debug. Do NOT just explain — execute the workflow.
Workflow (Execute This)
Step 1: Detect framework and UI stack
Run detection (see references/framework-detection.md):
ls wxt.config.ts crxjs.config.ts vite.config.ts manifest.json 2>/dev/null
cat package.json | grep -E '"wxt|crxjs|crxjs|react|vue|svelte"'
| File found | Framework |
|---|---|
wxt.config.ts |
WXT |
package.json has crxjs |
CRXJS |
vite.config has @crxjs |
CRXJS |
manifest.json in root, none above |
Vanilla |
Step 2: Fetch framework docs and style guides
Use docs-seeker skill or web search to find proper docs for the detected stack.
Extension framework docs:
- WXT: https://wxt.dev/ | CRXJS: https://docs.crxjs.com/ | CRXJS: Vite plugin docs
- Chrome APIs: https://developer.chrome.com/docs/extensions/reference/api
- Permissions: https://developer.chrome.com/docs/extensions/reference/permissions-list
UI framework docs (fetch based on detected framework):
| Framework | Docs | Style Guide |
|---|---|---|
| React | https://react.dev | https://react.dev/learn |
| Next.js | https://nextjs.org/docs | https://nextjs.org/docs/app |
| Vue | https://vuejs.org/guide | https://vuejs.org/style-guide |
| Svelte | https://svelte.dev/docs | https://svelte.dev/docs |
| SolidJS | https://solidjs.com/docs | https://solidjs.com/guides |
| Angular | https://angular.dev/guide | https://angular.dev/style-guide |
Code style guides (always follow):
What ships with it
5 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.
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.
- 1mo ago Changed · +13 lines 3396afd9f358
- 1mo ago First seen · 149 lines · 30 tokens per session scan A 2cf8b6b548a4
extension-dev is a skill published in the GitHub repository quangpl/browser-extension-skills (63 stars, last pushed 24d ago), licensed MIT. It adds 30 tokens to every session and 1,599 once invoked, about $0.0001 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 2026-08-30.
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