Agent skill · Anthropic

Web App Testing skill for Claude Code, Codex and Cursor

Uses Playwright to drive a local web app, check behavior, read console logs and take screenshots.

Officialname: webapp-testing★ 184k (repo)pushed 2026-10-09See repoSKILL.md on GitHubchecked 2026-11-07

What it does, in the publisher's words

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.

The description field of the SKILL.md. The agent reads only this at startup and decides from it when to load the full skill.

Install Web App Testing

The skills CLI copies the skill into the folder of each agent you pick (Claude Code, Codex, Cursor, Copilot, Gemini CLI, OpenCode, Windsurf...). Add -g for all projects. Needs Node.js 22.20+. docs

npx skills add anthropics/skills --skill webapp-testing

This repo is a plugin marketplace. Inside Claude Code, add it and install the plugin that holds the skill (document-skills, example-skills, claude-api, academy-guide...), or copy only this skill into ~/.claude/skills. docs

/plugin marketplace add anthropics/skills
/plugin install <plugin>@anthropic-agent-skills

# or only this skill:
npx skills add anthropics/skills --skill webapp-testing -a claude-code

Download the skill folder, zip it, then Customize > Skills > + > Create skill > Upload a skill. Code execution must be on (Settings > Capabilities). docs

git clone --depth 1 https://github.com/anthropics/skills.git /tmp/webapp-testing-src
cp -r /tmp/webapp-testing-src/skills/webapp-testing ./webapp-testing
zip -r webapp-testing.zip webapp-testing

Codex reads skills from .agents/skills in the repo or ~/.agents/skills. Type $ in Codex to use one. docs

npx skills add anthropics/skills --skill webapp-testing -a codex

gh skill (GitHub CLI 2.90+, preview) installs it for Copilot in VS Code, the CLI and the cloud agent. Copilot also reads .github/skills and ~/.copilot/skills. docs

gh skill install anthropics/skills webapp-testing

Cursor reads .cursor/skills, .agents/skills and ~/.cursor/skills (and .claude/skills). It does not install loose skills from a GitHub URL, so copy it in. docs

npx skills add anthropics/skills --skill webapp-testing -a cursor

Installs from the GitHub repo; --path picks this skill out of the repo. Default scope is user (all projects). docs

gemini skills install https://github.com/anthropics/skills.git --path skills/webapp-testing

OpenCode reads .opencode/skills, ~/.config/opencode/skills and the Claude and .agents folders. docs

npx skills add anthropics/skills --skill webapp-testing -a opencode

Windsurf (now Devin Desktop) reads .devin/skills, .windsurf/skills and ~/.codeium/windsurf/skills. docs

npx skills add anthropics/skills --skill webapp-testing -a windsurf

Works with

Claude Code, Claude.ai and Claude Desktop, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and other agents that read the open Agent Skills format.

Bundles 4 Python scripts the agent can run, so it needs Python on the machine. In the Claude apps, code execution must be on.

What's in the SKILL.md

6 sections

Decision Tree: Choosing Your Approach
Example: Using with_server.py
Reconnaissance-Then-Action Pattern
Common Pitfall
Best Practices
Reference Files

Bundled files

LICENSE.txt
examples/console_logging.py
examples/element_discovery.py
examples/static_html_automation.py
scripts/with_server.py

Loaded only when the instructions point to them.

Facts

Skill name: webapp-testing
Publisher: Anthropic (official)
Repo: anthropics/skills
License: Complete terms in LICENSE.txt
SKILL.md size: 281 words, 90 lines
Bundled files: 5, 4 scripts (Python)
Repo stars: 184k (as of 2026-10-24)
SKILL.md checked: 2026-11-07

Pairs with the Playwright MCP server: the server gives the agent the tools, the skill teaches it how to use them.

More skills from anthropics/skills

Canvas Design: Produces posters and static artwork as PNG or PDF files, guided by a written design philosophy.
Claude API: Reference for building on the Claude API and Anthropic SDKs: models, tool use, streaming, caching, pricing.
Doc Co-authoring: Walks you through drafting specs, proposals and design docs step by step with Claude.
Word Documents (DOCX): Creates, reads and edits Word .docx files, including templates, tracked changes and formatting.
Frontend Design: Steers UI work toward deliberate visual direction and typography instead of generic template looks.
MCP Server Builder: Guide for designing and building Model Context Protocol servers that wrap external APIs as tools.
PDF: Extracts text and tables, merges, splits, fills forms and creates PDF files.
PowerPoint (PPTX): Builds, reads and edits PowerPoint decks and templates, including layouts and speaker notes.
Skill Creator: Helps write new skills, refine existing ones and test how well they trigger and perform.
Slack GIF Creator: Makes small animated GIFs sized and validated for Slack's emoji and message limits.
Web Artifacts Builder: Builds multi-component HTML artifacts with React, Tailwind and shadcn/ui, bundled into one file.
Excel Spreadsheets (XLSX): Opens, cleans, edits and creates spreadsheets (.xlsx, .csv), including formulas and charts.

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FAQ

What does the webapp-testing skill do?+

Uses Playwright to drive a local web app, check behavior, read console logs and take screenshots. In its own SKILL.md, Anthropic describes it as: "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."

How do I install the webapp-testing skill?+

Run npx skills add anthropics/skills --skill webapp-testing and pick your agents, or use the tab for your agent above. In Claude Code the skill ends up in ~/.claude/skills/webapp-testing/SKILL.md; in Codex and Cursor in .agents/skills/webapp-testing/.

Does Web App Testing work in Codex, Cursor and Copilot, or only Claude?+

It's a standard SKILL.md, so any agent that reads the Agent Skills format can use it: Claude Code, the Claude apps, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and more.

Who maintains Web App Testing?+

Anthropic, the company or project behind it, in the anthropics/skills repo on GitHub, last pushed 2026-10-09. License: Complete terms in LICENSE.txt.

Read a skill's SKILL.md and scripts before you install it: skills aren't verified by any agent vendor. Claude skills marketplace · How to install skills · MCP servers