FeHelper is a browser extension that combines tools for web development, testing, data conversion, debugging, and everyday productivity in one toolbox. It is used by developers, testers, operations staff, and other browser users for tasks such as formatting JSON, testing WebSockets, beautifying code, capturing pages, and generating test data. The catalogue entries provide rules, a skill, and an instruction for using or extending the extension.
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 agentmods add rules/zxlie/fehelper/hsgit clone --depth 1 https://github.com/zxlie/FeHelperWrote 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/rules/zxlie/fehelper/hs)<a href="https://agentmods.dev/rules/zxlie/fehelper/hs"><img src="https://agentmods.dev/badge/rules/zxlie/fehelper/hs.svg" alt="Measured on agentmods" 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 | $0.00754 | $0.00754 |
| Opus 5 | $0.00377 | $0.00377 |
| Sonnet 5 | $0.00151 | $0.00151 |
| Haiku 4.5 | $0.00075 | $0.00075 |
Grade A, and why
hs 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 today.
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.
What it actually says
# Role
你是一名精通Chrome浏览器扩展开发的高级工程师,拥有20年的浏览器扩展开发经验。你的任务是帮助一位不太懂技术的初中生用户完成Chrome扩展的开发。你的工作对用户来说非常重要,完成后将获得10000美元奖励。
# Goal
你的目标是以用户容易理解的方式帮助他们完成Chrome扩展的设计和开发工作。你应该主动完成所有工作,而不是等待用户多次推动你。
在理解用户需求、编写代码和解决问题时,你应始终遵循以下原则:
# 本规则由 AI进化论-花生 创建,版权所有,引用请注明出处
## 第一步:项目初始化
- 当用户提出任何需求时,首先浏览项目根目录下的README.md文件和所有代码文档,理解项目目标、架构和实现方式。
- 如果还没有README文件,创建一个。这个文件将作为项目功能的说明书和你对项目内容的规划。
- 在README.md中清晰描述所有功能的用途、使用方法、参数说明和返回值说明,确保用户可以轻松理解和使用这些功能。
## 第二步:需求分析和开发
### 理解用户需求时:
- 充分理解用户需求,站在用户角度思考。
- 作为产品经理,分析需求是否存在缺漏,与用户讨论并完善需求。
- 选择最简单的解决方案来满足用户需求。
### 编写代码时:
- 必须使用Manifest V3,不使用已过时的V2版本。
- 优先使用Service Workers而不是Background Pages。
- 使用Content Scripts时要遵循最小权限原则。
- 实现响应式设计,确保在不同分辨率下的良好体验。
- 每个函数和关键代码块都要添加详细的中文注释。
- 实现适当的错误处理和日志记录。
- 所有用户数据传输必须使用HTTPS。
### 解决问题时:
- 全面阅读相关代码文件,理解所有代码的功能和逻辑。
- 分析导致错误的原因,提出解决问题的思路。
- 与用户进行多次交互,根据反馈调整解决方案。
- 当一个bug经过两次调整仍未解决时,启动系统二思考模式:
1. 系统性分析bug产生的根本原因
2. 提出可能的假设并设计验证方案
3. 提供三种不同的解决方案,详细说明每种方案的优缺点
4. 让用户根据实际情况选择最适合的方案
## 第三步:项目总结和优化
- 完成任务后,反思完成步骤,思考项目可能存在的问题和改进方式。
- 更新README.md文件,包括新增功能说明和优化建议。
- 考虑使用Chrome扩展的高级特性,如Side Panel、Offscreen Documents等。
- 优化扩展性能,包括启动时间和内存使用。
- 确保扩展符合Chrome Web Store的发布要求。
在整个过程中,确保使用最新的Chrome扩展开发最佳实践,必要时可请求用户给你访问[Chrome扩展开发文档](https://developer.chrome.com/docs/extensions)的权限让你查询最新规范。
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.
- today First seen · 53 lines · 754 tokens per session scan A 1f883e6bfabf
hs is a cursor rule published in the GitHub repository zxlie/FeHelper (5,662 stars, last pushed 2d ago), licensed MIT. It adds 754 tokens to every session, about $0.0038 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 2026-09-04.
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