webapp-testing

Q: How do I install webapp-testing?

Run npx skills add https://github.com/composiohq/awesome-claude-skills --skill webapp-testing in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/webapp-testing/ (personal) or .claude/skills/webapp-testing/ (project).

by composiohqTesting & QA

Toolkit for interacting with and testing local web applications using Playwright. Supports verifying frontend functionality, debugging UI behavior, capturing browser screenshots, and viewing browser logs.

Installs: 4.7K
Last 24h: +28
Trending rank: #4523
Security: Warn

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/composiohq/awesome-claude-skills --skill webapp-testing

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads webapp-testing automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

Security audits

Independent scans of the skill's instructions and bundled files.

Gen Agent Trust Hub PassSAFE ·The skill provides tools for local web application testing using Playwright. It includes a helper script that executes shell commands to manage local servers. The skill's workflow involves reading web content (DOM and console logs), which creates a surface for indirect prompt injection if the web application is untrusted.

Socket Warn1 alert: gptAnomaly

Snyk PassLOW ·Risk: LOW · No issues

Runlayer WarnMEDIUM ·6/6 files flagged

ZeroLeaks PassNONE ·Score: 93/100 · 2 sections analyzed

SKILL.md

The instructions your agent reads when the skill is triggered.

Web Application Testing

To test local web applications, write native Python Playwright scripts.

Helper Scripts Available:

scripts/with_server.py - Manages server lifecycle (supports multiple servers)

Always run scripts with --help first to see usage. DO NOT read the source until you try running the script first and find that a customized solution is abslutely necessary. These scripts can be very large and thus pollute your context window. They exist to be called directly as black-box scripts rather than ingested into your context window.

Decision Tree: Choosing Your Approach

User task → Is it static HTML?
    ├─ Yes → Read HTML file directly to identify selectors
    │         ├─ Success → Write Playwright script using selectors
    │         └─ Fails/Incomplete → Treat as dynamic (below)
    │
    └─ No (dynamic webapp) → Is the server already running?
        ├─ No → Run: python scripts/with_server.py --help
        │        Then use the helper + write simplified Playwright script
        │
        └─ Yes → Reconnaissance-then-action:
            1. Navigate and wait for networkidle
            2. Take screenshot or inspect DOM
            3. Identify selectors from rendered state
            4. Execute actions with discovered selectors

Example: Using with_server.py

To start a server, run --help first, then use the helper:

Single server:

python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py

Multiple servers (e.g., backend + frontend):

python scripts/with_server.py \
  --server "cd backend && python server.py" --port 3000 \
  --server "cd frontend && npm run dev" --port 5173 \
  -- python your_automation.py

To create an automation script, include only Playwright logic (servers are managed automatically):

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.chromium.launch(headless=True) # Always launch chromium in headless mode
    page = browser.new_page()
    page.goto('http://localhost:5173') # Server already running and ready
    page.wait_for_load_state('networkidle') # CRITICAL: Wait for JS to execute
    # ... your automation logic
    browser.close()

Reconnaissance-Then-Action Pattern

Inspect rendered DOM:

page.screenshot(path='/tmp/inspect.png', full_page=True)
content = page.content()
page.locator('button').all()

Identify selectors from inspection results
Execute actions using discovered selectors

Common Pitfall

❌ Don't inspect the DOM before waiting for networkidle on dynamic apps ✅ Do wait for page.wait_for_load_state('networkidle') before inspection

Best Practices

Use bundled scripts as black boxes - To accomplish a task, consider whether one of the scripts available in scripts/ can help. These scripts handle common, complex workflows reliably without cluttering the context window. Use --help to see usage, then invoke directly.
Use sync_playwright() for synchronous scripts
Always close the browser when done
Use descriptive selectors: text=, role=, CSS selectors, or IDs
Add appropriate waits: page.wait_for_selector() or page.wait_for_timeout()

Reference Files

examples/ - Examples showing common patterns:
- element_discovery.py - Discovering buttons, links, and inputs on a page
- static_html_automation.py - Using file:// URLs for local HTML
- console_logging.py - Capturing console logs during automation

FAQ

What does the webapp-testing skill do?

How do I install webapp-testing?

Run npx skills add https://github.com/composiohq/awesome-claude-skills --skill webapp-testing in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/webapp-testing/ (personal) or .claude/skills/webapp-testing/ (project).

Which AI agents can use webapp-testing?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is webapp-testing safe to install?

Security partners have reviewed it: Gen Agent Trust Hub passed; Socket flagged items to review; Snyk passed; Runlayer flagged items to review; ZeroLeaks passed. As with any skill, read the SKILL.md and bundled scripts before installing.

Who maintains webapp-testing?

It is published by composiohq in composiohq/awesome-claude-skills. It has 4,708 recorded installs.