browser-debugging

browser-debugging is a skill for Claude Code, Codex from aj-geddes/useful-ai-prompts. It costs 28 tokens per session (453 once invoked), scanned A, original, MIT.

A guide to finding problems in code that runs in a web browser, using browser developer tools. It covers JavaScript errors, page layout and styling, network requests, user interactions, animations, and performance.

In plain words
What is it for?
Use it to inspect and edit HTML and CSS, read errors and logs, pause code with breakpoints, examine variables, check network requests, and investigate slow or broken interactions.
Why use it?
Browser problems can be difficult to locate because the issue may be in the page structure, styles, scripts, or requests to a server. Developer tools show what the browser is receiving and doing.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to inspect and edit HTML and CSS, read errors and logs, pause code with breakpoints, examine variables, check network requests, and investigate slow or broken interactions.

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Install with agentmods
npx agentmods add skills/aj-geddes/useful-ai-prompts/browser-debugging
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.

Any agent
npx skills add aj-geddes/useful-ai-prompts --skill browser-debugging
Clone the repo
git clone --depth 1 https://github.com/aj-geddes/useful-ai-prompts

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 browser-debugging

README.md
[![agentmods](https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/browser-debugging/github.svg)](https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/browser-debugging)
Your own site
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/browser-debugging"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/browser-debugging/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for browser-debugging

Your own site · 80×15
<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/browser-debugging"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/browser-debugging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 453 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 18 Mar 2026
  • Snyk pass 5 Mar 2026
How audits are shown
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 5.1 $0.00028 $0.00453
Opus 5 $0.00014 $0.00227
Sonnet 5 $0.00006 $0.00091
Haiku 4.5 $0.00003 $0.00045

Measured 9d ago against content hash 535bd0eefcb6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

browser-debugging 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 9d 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.

skills/browser-debugging/SKILL.md · 89 lines

What it actually says

Browser Debugging

Table of Contents

Overview

Browser debugging tools help identify and fix client-side issues including JavaScript errors, layout problems, and performance issues.

When to Use

  • JavaScript errors
  • Layout/styling issues
  • Performance problems
  • User interaction issues
  • Network request failures
  • Animation glitches

Quick Start

Minimal working example:

Chrome DevTools Tabs:

Elements/Inspector:
  - Inspect HTML structure
  - Edit HTML/CSS in real-time
  - View computed styles
  - Check accessibility tree
  - Modify DOM

Console:
  - View JavaScript errors
  - Execute JavaScript
  - View console logs
  - Monitor messages
  - Clear errors

Sources/Debugger:
  - Set breakpoints
  - Step through code
  - Watch variables
  - Call stack view
  - Conditional breakpoints

Network:
  - View all requests
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide Contents
Browser DevTools Fundamentals Browser DevTools Fundamentals
Debugging Techniques Debugging Techniques
Common Issues & Solutions Common Issues & Solutions
Performance Debugging Performance Debugging

Best Practices

✅ DO

  • Follow established patterns and conventions
  • Write clean, maintainable code
  • Add appropriate documentation
  • Test thoroughly before deploying

❌ DON'T

  • Skip testing or validation
  • Ignore error handling
  • Hard-code configuration values
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. 9d ago First seen · 89 lines · 28 tokens per session scan A 535bd0eefcb6

Subscribe to this mod's changes

browser-debugging is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (334 stars, last pushed 6mo ago), licensed MIT. It adds 28 tokens to every session and 453 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 2026-08-30.

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