webapp-testing

webapp-testing is a skill for Claude Code, Codex from uwuclxdy/agenticat. It costs 24 tokens per session (1,174 once invoked), scanned A, original, MIT.

A Playwright toolkit for testing local web applications in a real browser. It supports navigation, clicks, form input, screenshots, console logs, and server management.

In plain words
What is it for?
Testing local web pages and apps, filling forms, checking interactions, taking screenshots, inspecting console output, and managing test servers.
Why use it?
It helps check how a web app behaves through its interface and capture browser errors that ordinary code checks may miss.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/uwuclxdy/agenticat/webapp-testing
Any agent
npx skills add uwuclxdy/agenticat --skill webapp-testing
Clone the repo
git clone --depth 1 https://github.com/uwuclxdy/agenticat

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for webapp-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/uwuclxdy/agenticat/webapp-testing.svg)](https://agentmods.dev/skills/uwuclxdy/agenticat/webapp-testing)
Your own site
<a href="https://agentmods.dev/skills/uwuclxdy/agenticat/webapp-testing"><img src="https://agentmods.dev/badge/skills/uwuclxdy/agenticat/webapp-testing.svg" alt="Measured on agentmods" height="20"></a>
Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,174 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00024 $0.01174
Opus 5 $0.00012 $0.00587
Sonnet 5 $0.00005 $0.00235
Haiku 4.5 $0.00002 $0.00117

Measured 4d ago against content hash 8a593c36ead7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

webapp-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (examples/console_logging.py, examples/element_discovery.py, examples/static_html_automation.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/webapp-testing/SKILL.md · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Vendored from anthropics/skills under Apache-2.0. Modified: description rewrite, a Delegating section pointing at the paired webapp-tester agent shipped in this repo, and a tone pass (emoji and all-caps emphasis removed).

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. Don't read the source until the script has been run and shown not to fit the task. These scripts can be large; reading them pollutes your context window. They exist to be called directly as black boxes.

Decision Tree: Choosing Your Approach

UI/frontend only. For pure backend/API assertions without a browser, use Playwright's request context or a plain HTTP client instead (see Limits).

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

Read the full file on GitHub · 113 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 113 lines · 24 tokens per session scan A 8a593c36ead7

Subscribe to this mod's changes

webapp-testing is a skill published in the GitHub repository uwuclxdy/agenticat (5 stars, last pushed 4d ago), licensed MIT. It adds 24 tokens to every session and 1,174 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.