webapp-testing: a Claude Code skill by Anthropic
Official
For developers who want Claude to click through a web app running on their own machine and see what breaks. Skip it if the site is only live on a remote server.
Before you install: It tells Claude to run the bundled with_server.py helper as a black box and not read its source first.
- Score
- 86of 100
- Rank
- #22of 239
- Installs
- 203Kon skills.sh
- Security
- Mixed 5 scanners
- Updated
- 2026
- Context
- ~54tokens always
Install
npx skills add https://github.com/anthropics/skills --skill webapp-testing
Run it in your terminal. View the source
Using the Claude app rather than Claude Code? You can add a skill there too. How to add it in the app
What does webapp-testing do?
webapp-testing is a skill that has Claude check a web app on your own machine by writing Python Playwright scripts. It starts with a choice: for a static HTML file, Claude reads the markup to find selectors; for a dynamic app, it starts the server if needed with the bundled with_server.py helper, which can launch a backend and frontend together. Claude then opens headless Chromium, waits for the network to go idle, takes a screenshot or reads the DOM, and only then clicks or types with the selectors it found. Example scripts cover finding buttons and inputs, local file:// pages and capturing console logs.
When should you use webapp-testing?
Use it when
- Checking that a new form or button works in the browser
- Your local frontend and backend both need to run for a test
- You want screenshots or console logs from a local page
Skip it when
- You need unit tests for code with no browser involved
- The app you want to check is not running locally
What it needs and what it can touch
You need
- Python with the Playwright library and its Chromium browser
What it can do
- Runs shell commands and Python scripts
- Starts your local dev servers through a bundled helper
- Opens your local app in a headless Chromium browser
- Saves screenshots to your machine
From reading its instructions, not from running it.
Why it scores 86
Strongest on upkeep (100 of 100), weakest on adoption (74).
Is webapp-testing safe to install?
At least one scanner raised a medium warning. Read the results below. Scanners often miss what other scanners catch, and a skill can change after a scan. Read its source before you install it.
| Scanner | Result | Date |
|---|---|---|
| Gen Agent Trust Hub | Passed | Sep 14, 2026 |
| Socket | Medium risk | Sep 14, 2026 |
| Snyk | Medium risk | Sep 14, 2026 |
| Runlayer | Medium risk | Feb 26, 2026 |
| ZeroLeaks | Passed | Apr 16, 2026 |
Details
- Installs
- 202,664
- Repository stars
- 192,526
- Last repository change
- Tokens always loaded
- about 54
- Tokens when used
- about 893
- License
- Apache-2.0
- Data confidence
- High
Did it do the job for you?
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webapp-testing