RES plugin
RES studies a SaaS product in the browser and builds a knowledge base for rebuilding it: screens, rules, data model, report.
- 294 ★ on the repository
- Last commit
- MIT
Broad access
Why this level
- The agent drives a real browser in your accounts and can modify test data.
- Studying someone else's product may violate its terms of use.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add plugins/resDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewBroad accessThe tool can change data, run commands or handle secrets.
- The agent drives a real browser in your accounts and can modify test data.
- Studying someone else's product may violate its terms of use.
This is third-party code. Review the repository files before installing.
What it does
RES, Reverse Engineering SaaS, is a Claude Code skill. The agent explores a web product in a test environment and writes screens, components, business rules as Given/When/Then, flows, entities with fields, API request templates and design tokens into files, logging every change it makes in `sandbox/ledger.csv`. The output is two files: `REPORT.html` with an overview and decisions to make, and a `re-<product>-handoff-<date>.zip` archive for any agent. Work follows safety levels from a trial account in a separate Chrome profile to observe-only mode on production. The agent sends no messages, touches no billing and types no passwords.
Who it is for. Teams that want to rebuild an internal service or launch a product for their market and will study it on their own trial accounts.
Good fit when
- A CRM the team relies on must be documented to move it to your own platform.
- Before launching an alternative a catalog of screens and rules with evidence is required.
- A contractor needs an archive with the data model and a build plan.
- A product is studied without risk to live data because every change is logged.
Not a fit when
- You have no right to study the product because terms or contract forbid it.
- You need access to live customer data, while the tool works with test data only.
- The agent cannot drive a browser: Claude in Chrome, Playwright MCP or Chrome DevTools MCP is needed.
Example request
Study Pipedrive on a trial account in a separate profile, ask nothing until done, and send REPORT.html and the archive.Limitations
The skill drives a real browser on your accounts, so study only permitted products and use a trial account in a separate Chrome profile. Node.js 22 or newer and an agent with a browser tool are required. Autosave and read receipts count as writes and must be reverted. A product's terms and intellectual property law limit rebuilding, and responsibility is yours. The result describes behavior, not source code.
How to disable. Remove the plugin with `claude plugin uninstall res@res` or the `reverse-engineering-saas` folder from the skills directory. Delete the trial account and Chrome profile separately.
FAQ
What is the output?
Two files: `REPORT.html` to read and a `re-<product>-handoff-<date>.zip` with the knowledge base for an agent or team.
What does the agent never do?
It never sends messages or invites, touches billing, creates accounts or types passwords.
How do the safety levels work?
From L1, a trial account in a separate profile, to L4, observing production with no writes. Every change goes to the ledger.
Which agent is needed?
Any agent that reads skills and drives a browser: Claude in Chrome, Playwright MCP or Chrome DevTools MCP.
How many tokens does the skill add?
About 130 tokens per session and about 4,600 when it runs, as measured by `claude plugin details`.
Discussion
No questions or reviews yet.
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README in short
The README covers installation, preparing a safe environment, phases, knowledge base contents, safety levels and an FAQ. It includes sample reports for Pipedrive.