before-after

before-after is a skill for Claude Code from soumyachk101/VibeLens. It costs 61 tokens per session (878 once invoked), scanned A, original, MIT.

A visual verification workflow that captures the same webpage before and after an edit and compares the results. It uses identical URL, viewport, full-page, and loading-delay settings for both captures.

In plain words
What is it for?
Use it to verify layout or styling changes, record console and request problems, and report exactly what changed between the two screenshots.
Why use it?
It replaces a guess about whether a UI fix worked with a concrete comparison of the page and its diagnostic information.

Skill for Claude Code

Written for Claude Code: $ARGUMENTS substitution.

Part of the vibelens plugin — 12 skills, 4 agents, 1 hook shipped together

Good fit Use it to verify layout or styling changes, record console and request problems, and report exactly what changed between the two screenshots.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/soumyachk101/vibelens/before-after
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 soumyachk101/VibeLens --skill before-after
Clone the repo
git clone --depth 1 https://github.com/soumyachk101/VibeLens

Made for: Claude Code.

Or install vibelens, the plugin that ships this one along with the rest of its 12 skills, 4 agents, 1 hook.

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 before-after

README.md
[![agentmods](https://agentmods.dev/badge/skills/soumyachk101/vibelens/before-after/github.svg)](https://agentmods.dev/skills/soumyachk101/vibelens/before-after)
Your own site
<a href="https://agentmods.dev/skills/soumyachk101/vibelens/before-after"><img src="https://agentmods.dev/badge/skills/soumyachk101/vibelens/before-after/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 before-after

Your own site · 80×15
<a href="https://agentmods.dev/skills/soumyachk101/vibelens/before-after"><img src="https://agentmods.dev/badge/skills/soumyachk101/vibelens/before-after.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 878 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.
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 $0.00061 $0.00878
Opus 5 $0.00030 $0.00439
Sonnet 5 $0.00012 $0.00176
Haiku 4.5 $0.00006 $0.00088

Measured 10d ago against content hash d74ac3edddf3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

before-after 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 10d 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.

plugin/skills/before-after/SKILL.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Before and after

Target: $ARGUMENTS — the URL, and the change to make or verify (if either is missing, ask).

An edit is a hypothesis. The only thing that settles it is two captures of the same page taken under the same conditions. Do this whenever you claim something is fixed.

Steps

  1. Capture before. Call inspect_localhost_ui and write down the exact parameter set you used: url, viewport, fullPage, delay. Choose them deliberately now, because you are committed to them for the rest of the task. Prefer fullPage: true when the change could shift anything below the fold, and a delay high enough that the page is fully hydrated — a comparison against a half-rendered baseline is worthless.

  2. Record the baseline in writing, not just as an image you will forget:

    • the four diagnostic counts from summary (consoleErrors, consoleWarnings, uncaughtPageErrors, failedRequests)
    • summary.pageTitle and summary.domTruncated
    • the class list of every element you are about to touch, copied verbatim from simplifiedDOM
    • one sentence on the visible defect in the screenshot
  3. Make the change. One coherent change at a time. If you edit three unrelated things and the after-capture is still wrong, the comparison tells you nothing about which one failed.

  4. Capture after with byte-identical parameters. Same url, same viewport, same fullPage, same delay.

    A different viewport changes layout, so every difference you see is the viewport, not your fix. fullPage: true versus false changes the image dimensions and which lazy content loaded. A shorter delay can catch the page mid-hydration and invent a regression; a longer one can let an async error appear that was always there. If any parameter differs, the comparison is meaningless — discard it and capture again correctly. If you must change a parameter (for example, the baseline delay was too short), re-take both captures under the new settings and say that you did.

Read the full file on GitHub · 71 lines

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. 10d ago First seen · 71 lines · 61 tokens per session scan A d74ac3edddf3

Subscribe to this mod's changes

before-after is a skill published in the GitHub repository soumyachk101/VibeLens (0 stars, last pushed 4d ago), licensed MIT. It adds 61 tokens to every session and 878 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.