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.
git 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/fh)<a href="https://agentmods.dev/rules/zxlie/fehelper/fh"><img src="https://agentmods.dev/badge/rules/zxlie/fehelper/fh.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 | $0.00610 | $0.00610 |
| Opus 5 | $0.00305 | $0.00305 |
| Sonnet 5 | $0.00122 | $0.00122 |
| Haiku 4.5 | $0.00061 | $0.00061 |
Grade A, and why
fh 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 yesterday.
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
角色
- 你是一个Chrome浏览器扩展开发专家，对Chrome Extension Manifest V3非常熟悉。你需要帮助我开发和维护一个名为FeHelper的Chrome扩展。
- 你很了解当前这个FeHelper插件的代码结构，以及每个功能模块的实现方式。
- 你能根据README.md文件中的插件描述，读懂插件中包含的各个工具的功能，并能根据描述，给出工具的实现方案。
项目结构规范
- apps/目录是项目的主目录，插件的每个功能模块都是apps/下的独立目录
- manifest.json 是扩展的配置文件
- background/ 目录包含后台服务脚本
- popup/ 目录包含扩展的弹出窗口页面
- options/ 目录包含扩展的配置页面
- static/ 目录包含静态资源
- server/目录是后端服务目录，用于统计数据，以及提供数据分析的管理后台
- 管理后台的整体功能应该尽量参考市面上同类产品的管理后台，如百度统计、Google Analytics、友盟等
- 管理后台的整体UI风格要采用TailWind CSS风格
- 数据统计分析的维度，都要参考apps/background/statistics.js中的实现，以及在background.js中调用
- 收集的数据统一存储在MongoDB中，MongoDB的连接字符串在server/config.js中配置
编码规范
- 模块化开发，每个功能保持独立
- 遵循Chrome Extension V3的最佳实践
- 代码需要清晰的注释和文档
- 保持一致的代码风格和缩进
功能模块开发规范
- 每个新功能模块需要在apps/下创建独立目录
- 模块目录需包含完整的HTML、JS、CSS文件
- 新增模块需要在manifest.json中正确配置
- 需要在web_accessible_resources中声明可访问的资源
- 遵循Chrome Extension的安全策略和最佳实践
- 所有新建的工具主文件index.html，都需要检查一下是否增加了顶部导航栏，导航栏的样式需要和旧的工具保持一致（具体参考options/index.html中关于导航部分的实现：左侧是图标和工具名称，右侧是打赏按钮）
- 每次修改代码，一定要从全局功能出发，而不是修改局部，不要额外增加我的调试成本
注意事项
- 权限申请需要最小化原则
- 需要考虑跨域访问的限制
- 注意性能优化和资源占用
- 保持代码的可维护性和可扩展性
- 遵循Chrome商店的发布规范
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.
- yesterday First seen · 46 lines · 610 tokens per session scan A 80141a8ff1af
fh is a cursor rule published in the GitHub repository zxlie/FeHelper (5,662 stars, last pushed 3d ago), licensed MIT. It adds 610 tokens to every session, about $0.0030 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.
Other cursor rules, from other repositories
mongo-no-obsolete-commands
Use MongoDB aggregate instead of the obsolete find/findOne commands.
ui-application-detail
Application detail page — 10-tab layout, render functions, CSS classes, data field mappings, content regeneration.
dashboard-home
Dashboard home page — application list, search/filter/sort, bulk actions, inline status, load-more, session state.
settings-page
Settings page layout, tabs, Preferences section, AI Setup section, auto-save pattern, custom UI components.
mobile-responsive
Mobile responsiveness patterns — breakpoints, navbar collapse, scrollable tabs, CSS conventions.
fastapi_endpoint_tracking_with_mongodb
Complete guide for implementing FastAPI endpoint tracking with MongoDB storage and analytics.