# Web App Testing

Test local web apps with Playwright, including screenshots and browser logs.

- Repository: https://github.com/anthropics/skills (186321 stars)
- Category: Testing
- License: Complete terms in LICENSE.txt
- Last updated: 2026-10-28
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add anthropics/skills --skill webapp-testing -g -a claude-code -y`
Codex: `npx skills add anthropics/skills --skill webapp-testing -g -a codex -y`
Cursor: `npx skills add anthropics/skills --skill webapp-testing -g -a cursor -y`
Gemini CLI: `npx skills add anthropics/skills --skill webapp-testing -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add anthropics/skills`

## Description

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.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# 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:**
```bash
python scripts/with_server.py --server "npm run dev" --port 5173 -- python your_automation.py
```

**Multiple servers (e.g., backend + frontend):**
```bash
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):
```python
from playwright.sync_api import sync_playwright

The rest: https://github.com/anthropics/skills/blob/HEAD/skills/webapp-testing/SKILL.md