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.
npx agentmods add skills/lll0k0lad/agent-skills/browser-testing-with-devtoolsnpx skills add LLl0k0laD/agent-skills --skill browser-testing-with-devtoolsgit clone --depth 1 https://github.com/LLl0k0laD/agent-skillsWrote 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.
[](https://agentmods.dev/skills/lll0k0lad/agent-skills/browser-testing-with-devtools)<a href="https://agentmods.dev/skills/lll0k0lad/agent-skills/browser-testing-with-devtools"><img src="https://agentmods.dev/badge/skills/lll0k0lad/agent-skills/browser-testing-with-devtools.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00052 | $0.01960 |
| Opus 5 | $0.00026 | $0.00980 |
| Sonnet 5 | $0.00010 | $0.00392 |
| Haiku 4.5 | $0.00005 | $0.00196 |
Grade A, and why
browser-testing-with-devtools 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 6d ago.
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.
How it starts
The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Browser Testing with DevTools
Overview
Use Chrome DevTools MCP to give your agent eyes into the browser. This bridges the gap between static code analysis and live browser execution — the agent can see what the user sees, inspect the DOM, read console logs, analyze network requests, and capture performance data. Instead of guessing what's happening at runtime, verify it.
When to Use
- Building or modifying anything that renders in a browser
- Debugging UI issues (layout, styling, interaction)
- Diagnosing console errors or warnings
- Analyzing network requests and API responses
- Profiling performance (Core Web Vitals, paint timing, layout shifts)
- Verifying that a fix actually works in the browser
- Automated UI testing through the agent
When NOT to use: Backend-only changes, CLI tools, or code that doesn't run in a browser.
Setting Up Chrome DevTools MCP
Installation
# Add Chrome DevTools MCP server to your Claude Code config
# In your project's .mcp.json or Claude Code settings:
{
"mcpServers": {
"chrome-devtools": {
"command": "npx",
"args": ["@anthropic/chrome-devtools-mcp@latest"]
}
}
}
Available Tools
Chrome DevTools MCP provides these capabilities:
| Tool | What It Does | When to Use |
|---|---|---|
| Screenshot | Captures the current page state | Visual verification, before/after comparisons |
| DOM Inspection | Reads the live DOM tree | Verify component rendering, check structure |
| Console Logs | Retrieves console output (log, warn, error) | Diagnose errors, verify logging |
| Network Monitor | Captures network requests and responses | Verify API calls, check payloads |
| Performance Trace | Records performance timing data | Profile load time, identify bottlenecks |
| Element Styles | Reads computed styles for elements | Debug CSS issues, verify styling |
| Accessibility Tree | Reads the accessibility tree | Verify screen reader experience |
| JavaScript Execution | Runs JavaScript in the page context | Interactive debugging, state inspection |
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.
- 6d ago First seen · 255 lines · 52 tokens per session scan A c64bf33a6620
browser-testing-with-devtools is a skill published in the GitHub repository LLl0k0laD/agent-skills (2 stars, last pushed yesterday), licensed MIT. It adds 52 tokens to every session and 1,960 once invoked, about $0.0003 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.
Other skills, from other repositories
browser-testing-with-devtools
Tests in real browsers via Chrome DevTools MCP. Use when building or debugging anything that runs in a browser. Use when you need to inspect the DOM, capture console errors, analyze network requests, profile performance, or verify visual output with real runtime data. Requires the chrome-devtools MCP server to be…
awt-e2e-testing
AI-powered E2E web testing — eyes and hands for AI coding tools. Declarative YAML scenarios, Playwright execution, visual matching (OpenCV + OCR), platform auto-detection (Flutter/React/Vue), learning DB. Install: npx skills add ksgisang/awt-skill --skill awt -g.
test-site
Tests a deployed, activated Power Pages site at runtime using browser-based navigation, page crawling, and API request verification via Playwright. Use when the user wants to test, verify, or smoke-test their deployed site.
test-engineer
Automated E2E testing with Playwright including the auto-fix loop — generate test cases from the UI, run them, fix failures and re-run until passing, then produce a human-readable report. Test until it passes, not just test and report. Drives /toh-test; use whenever tests must be written, run, or made green.
agent-browser
Automates browser interactions for web testing, form filling, screenshots, and data extraction. Use when the user needs to navigate websites, interact with web pages, fill forms, take screenshots, test web applications, or extract information from web pages.
playwright-skill
Complete browser automation with Playwright. Auto-detects dev servers, writes clean test scripts to /tmp. Test pages, fill forms, take screenshots, check responsive design, validate UX, test login flows, check links, automate any browser task. Use when user wants to test websites, automate browser interactions…