browser-extension-developer

browser-extension-developer is a skill for Claude Code, Codex from jiaxiaojunQAQ/SkillJect. It costs 43 tokens per session (306 once invoked), scanned A, original, no licence file.

A development guide for browser extensions that run in Chrome, Firefox, and Edge. Browser extensions are small programs that add features to a web browser.

In plain words
What is it for?
Use it for code in a browser extension’s browser, including page scripts, background scripts, compatibility work, and language updates.
Why use it?
It helps keep extension code and browser-specific parts organized when developing or maintaining it.

Skill for Claude CodeCodex

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 skills/jiaxiaojunqaq/skillject/browser-extension-developer
Any agent
npx skills add jiaxiaojunQAQ/SkillJect --skill browser-extension-developer
Clone the repo
git clone --depth 1 https://github.com/jiaxiaojunQAQ/SkillJect

Made for: Claude Code, Codex.

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 browser-extension-developer

README.md
[![agentmods](https://agentmods.dev/badge/skills/jiaxiaojunqaq/skillject/browser-extension-developer.svg)](https://agentmods.dev/skills/jiaxiaojunqaq/skillject/browser-extension-developer)
Your own site
<a href="https://agentmods.dev/skills/jiaxiaojunqaq/skillject/browser-extension-developer"><img src="https://agentmods.dev/badge/skills/jiaxiaojunqaq/skillject/browser-extension-developer.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 306 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00043 $0.00306
Opus 5 $0.00022 $0.00153
Sonnet 5 $0.00009 $0.00061
Haiku 4.5 $0.00004 $0.00031

Measured 4d ago against content hash 321c1470b387, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

browser-extension-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 4d 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.

data/skills_sample/browser-extension-developer/SKILL.md · 37 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 4d ago First seen · 37 lines · 43 tokens per session scan A 321c1470b387

Subscribe to this mod's changes

browser-extension-developer is a skill published in the GitHub repository jiaxiaojunQAQ/SkillJect (77 stars, last pushed 2mo ago), with no licence file. It adds 43 tokens to every session and 306 once invoked, about $0.0002 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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