screenshot-annotator

screenshot-annotator is a skill for Claude Code from ncklrs/claude-chrome-user-testing. It costs 0 tokens per session (2,145 once invoked), scanned A, original, MIT.

A tool for adding boxes, highlights, and numbered notes to screenshots from user testing. User testing means watching or recording people as they try to complete tasks in a product.

In plain words
What is it for?
Use it to mark errors, confusing controls, warnings, successful steps, and other notable areas in test screenshots. The marked images can support clearer usability and bug reports.
Why use it?
Plain screenshots can make it hard to see exactly what went wrong or confused someone. Annotations point reviewers to the relevant part of the screen.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the user-testing-agent plugin — 14 skills, 10 commands shipped together

Good fit Use it to mark errors, confusing controls, warnings, successful steps, and other notable areas in test screenshots. The marked images can support clearer usability and bug reports.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ncklrs/claude-chrome-user-testing/screenshot-annotator
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 ncklrs/claude-chrome-user-testing --skill screenshot-annotator
Clone the repo
git clone --depth 1 https://github.com/ncklrs/claude-chrome-user-testing

Made for: Claude Code.

Or install user-testing-agent, the plugin that ships this one along with the rest of its 14 skills, 10 commands.

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 screenshot-annotator

README.md
[![agentmods](https://agentmods.dev/badge/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator/github.svg)](https://agentmods.dev/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator)
Your own site
<a href="https://agentmods.dev/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator"><img src="https://agentmods.dev/badge/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator/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 screenshot-annotator

Your own site · 80×15
<a href="https://agentmods.dev/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator"><img src="https://agentmods.dev/badge/skills/ncklrs/claude-chrome-user-testing/screenshot-annotator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,145 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 $0.00000 $0.02145
Opus 5 $0.00000 $0.01073
Sonnet 5 $0.00000 $0.00429
Haiku 4.5 $0.00000 $0.00215

Measured 9d ago against content hash b3a3f7e2d215, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

screenshot-annotator 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/screenshot-annotator/SKILL.md · 311 lines

How it starts

The opening of the file, as written. The whole thing — 311 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Screenshot Annotator Skill

This skill provides visual annotation capabilities for screenshots taken during user testing. Annotations help highlight issues, confusion points, and notable elements in test screenshots.

Purpose

Add visual markers (boxes, highlights, callouts) to screenshots before capturing them. This makes test reports more actionable by clearly showing where issues occurred.

Annotation Types

Box

A rectangular border around an element.

Variant Border Style Use Case
error 3px solid red Form errors, broken functionality
confusion 3px dashed red User hesitation, unclear elements
warning 3px solid orange Frustration triggers, warnings
success 3px solid green Task completion, positive elements
info 3px solid blue General callouts

Highlight

A semi-transparent overlay on an element.

Color Opacity Use Case
Yellow 40% Draw attention to area
Orange 30% Frustration trigger match
Red 25% Critical issue area

Callout

A numbered circle positioned near an element, used for referencing multiple issues.

Color Palette

error/confusion: #dc2626 (red-600)
warning:         #f59e0b (amber-500)
success:         #16a34a (green-600)
info:            #2563eb (blue-600)
highlight:       #fbbf24 (amber-400)

How to Add Annotations

Use browser_evaluate to inject annotation elements before taking a screenshot. All DOM manipulation must use safe methods (createElement, appendChild, setAttribute).

Step 1: Get Element Position

First, find the target element and get its bounding box:

// Via browser_evaluate
const element = document.querySelector('[data-testid="submit-btn"]');
const rect = element.getBoundingClientRect();
const position = {
  x: rect.left + window.scrollX,
  y: rect.top + window.scrollY,
  width: rect.width,
  height: rect.height
};
return position;

Read the full file on GitHub · 311 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. 9d ago First seen · 311 lines · 0 tokens per session scan A b3a3f7e2d215

Subscribe to this mod's changes

screenshot-annotator is a skill published in the GitHub repository ncklrs/claude-chrome-user-testing (19 stars, last pushed 8mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,145 tokens. 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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