The UI Context Capture popup — capture UI context for your AI coding assistant.
UI Context Capture for AI Coders — Complete User Guide
Click · Capture · Prompt
Version 1.0 · Updated 2026
UI Context Capture for AI Coders is a Chrome extension that lets you click any UI element on a live web page and capture its complete context — CSS selector, computed styles, a cropped screenshot, and (when detectable) its React or Vue component name — all formatted into a ready-to-paste prompt for your AI coding assistant.
What Is UI Context Capture for AI Coders?
UI Context Capture is a Chrome extension that eliminates the ambiguity of describing UI bugs to AI assistants. Instead of saying "the button on the left is misaligned," you click the button and get a perfect structured context — selector, styles, screenshot, component name — ready to paste into Cursor, Claude Code, ChatGPT, or any AI tool.
It works with three capture modes: Element (click one thing), Viewport (capture the whole visible page), and Region (drag to select an area).
Who Should Use This Extension?
- Software developers — debugging UI issues and communicating with AI coding assistants.
- Frontend engineers — capturing component context for refactoring or bug fixes.
- QA engineers — documenting UI bugs with precise context for developers.
- Product designers — capturing UI elements for design handoff and documentation.
- Anyone who uses AI coding assistants — and wants to give them perfect context instead of vague descriptions.
Why You Can Trust UI Context Capture
🔒 Trust built in Local-first, private by default, and built with transparency.
UI Context Capture stores all captured data locally in your browser. No data is sent to external servers unless you explicitly connect your own Anthropic or OpenAI API key — and even then, calls go directly from your browser to that provider. The extension has no server of its own.
Battle-tested logic
Screenshot cropping tested at 1x and 2x/retina scaling, edge-clamping, and partial off-screen elements. Free-tier counter tested at under-limit, at-limit, and Pro-unlimited.
Documented calculations
Every formula is transparent and verifiable — no black-box algorithms.
100% local storage
All captured data (selectors, styles, screenshots, HTML snippets) stays in your browser.
No hidden data collection
Minimal permissions — only storage, alarms, activeTab, and scripting.
Why Use This Extension? (Key Benefits)
Key User Pain Points & How This Extension Solves Them
Instead of vague descriptions like "the button is misaligned," you get perfect structured context — selector, styles, screenshot, and component name.
Diff view shows exactly which styles changed between two captures of the same element — no more guessing what broke.
Console error capture includes errors from the 10 seconds before capture — so your AI assistant knows what broke at runtime.
Screenshot alone doesn't show the CSS. This extension captures both — a cropped screenshot AND the exact computed styles.
Anonymize toggle replaces class names with placeholders — share UI context without exposing internal naming conventions.
One click captures the complete context — selector, styles, HTML snippet, and errors — all formatted into a ready-to-paste prompt.
Why Upgrade to Monthly Pro?
🚀 Unlock the full power of UI Context Capture
The free tier gives you 5 captures per month forever — enough for occasional use. But if you're a developer who regularly uses AI coding assistants, the Pro plan removes all limits and gives you advanced capabilities.
🆓 Free
- 5 captures/month
- All 3 capture modes
- 5 built-in templates
- HTML snippet + console errors
- Diff view
- Anonymize toggle
- Custom prefix
- Full history
⭐ Pro
- Unlimited captures
- Custom prompt templates
- Everything in Free
- Priority support
📈 ROI
- 💸 $5/mo or $30/yr
- ⏱️ Saves 5+ hours/week
- 🤖 Better AI responses
- 🐛 Faster debugging
14‑day free trial included · cancel anytime
Features — Detailed Guide
1. Capture Modes
Element mode: Click any element on the page. A live hover tooltip shows its tag, class, and box-model dimensions before you click. Captures the selector, computed styles, a cropped screenshot of the element, and (when detectable) its React or Vue component name.
Viewport mode: Captures the whole visible page — no click needed. Perfect for full-page design reviews or documenting entire screens.
Region mode: Drag to select an area of the page. Captures a cropped screenshot of the selected region. Ideal for capturing specific sections without the surrounding noise.
2. AI-Ready Prompts
What it does: After capture, the extension generates a structured prompt containing:
- CSS selector — precise location of the element
- Computed styles — key CSS properties (display, position, width, height, margin, padding, color, etc.)
- Component name — React or Vue component name (when detectable — production builds often strip these names)
- HTML snippet — the element's outer HTML (truncated at 1200 characters)
- Recent console errors — runtime errors from the 10 seconds before capture
- Screenshot — cropped to the element or region
Why it matters: Instead of vague descriptions like "the button is misaligned," your AI assistant gets perfect, unambiguous context.
3. Diff View
What it does: When you capture the same element (same selector + same page URL) a second time, the results page shows exactly which computed style values changed since the prior capture.
Why it matters: Perfect for debugging CSS regressions — see exactly what changed between two states of the same component.
4. Anonymize Toggle
What it does: Replaces real class and ID names with generic placeholders (`.anon-class-1`, `.anon-class-2`) before the prompt is generated. The same class name always maps to the same placeholder, both within one capture and across calls.
Why it matters: Share UI context with AI tools without exposing internal class naming conventions — useful for proprietary codebases.
5. Console Error Capture
What it does: A minimal always-on content script listens for window.onerror and unhandledrejection events, buffering the last 60 seconds of errors. When you capture an element, the results page shows any errors that occurred in the 10 seconds before capture.
Why it matters: The most cited pain point for AI coding assistants is that they can't see runtime errors. Now they can — the AI gets the error message and source location alongside the UI context.
6. History & Reopen
What it does: The History page shows a browsable, searchable list of all your past captures with thumbnail previews. Click "Reopen" to view any capture again.
Why it matters: Reopening doesn't count against your monthly free-tier limit — it's a view, not a new capture. Perfect for revisiting previous work without burning your monthly allowance.
7. Prompt Templates & Custom Prefix
Built-in templates (free):
- Fix this bug — "This UI element has a bug. Please diagnose and fix it based on the context below."
- Improve styling — "Suggest an improved design for this UI element based on the context below."
- Explain the code — "Explain the logic and purpose of this UI element based on the context below."
- Add a feature — "Suggest how to add a new feature to this UI element based on the context below."
- Convert component — "Suggest how to convert or refactor this component based on the context below."
Custom prefix: A free-text field prepended to the generated prompt (e.g., "You are a senior frontend engineer...") — useful for setting system context before the element context.
Custom templates (Pro): Pro users can save their own prompt templates beyond the 5 built-in ones.
8. Keyboard Shortcut
What it does: Pressing Ctrl+Shift+U (or ⌘+Shift+U on Mac) starts the element picker directly — no need to open the popup first. This reduces friction on every single use.
Setup & Configuration
Installation
- Install UI Context Capture from the Chrome Web Store.
- Pin the extension icon to your toolbar for easy access.
- Navigate to any webpage and click the extension icon.
- Choose your capture mode and click "Pick Element on Page."
Connecting an AI API Key (Optional)
- Open the Settings page (Options).
- Select your provider (Anthropic or OpenAI).
- Paste your API key from the provider's console.
- Click Save.
🔒 Privacy note Your API key is stored locally and only used to call that provider's API directly from your browser — never sent anywhere else.
Customizing Prompt Templates (Pro)
- Upgrade to Pro for unlimited captures and custom templates.
- In the results page, select "Save as New Template" from the template dropdown.
- Your custom templates appear alongside the built-in ones.
Pricing: Free vs. Pro
- 5 captures/month
- All 3 capture modes
- 5 built-in templates
- HTML snippet + console errors
- Diff view
- Anonymize toggle
- Custom prefix
- Full history
- Unlimited captures
- Custom prompt templates
- Everything in Free
- Priority support
One Pro subscription covers all features. Get your license at muhiuddinalam.gumroad.com/l/contextcapture. Annual plan: $30/year.
Data Privacy, Performance & Permissions
- 🔒 Local‑only storage: All captured data (selectors, styles, screenshots, HTML snippets) is stored exclusively in your browser using
chrome.storage.localandchrome.storage.session. - ⚡ On-demand injection: The picker script is injected only when you click "Pick Element" — not running persistently on every page.
- 🛡️ Minimal permissions: Only
storage,alarms,activeTab, andscripting. - 🔍 Console error capture: A minimal passive content script buffers errors in memory — nothing is read, stored, or sent unless a capture happens afterward.
Common Mistakes to Avoid
Fix: React/Vue component names are often stripped in production. When the tool says "Not detected," it's being honest — the heuristic couldn't find a name because the build process removed it. The selector and styles are still captured perfectly.
Fix: The free tier resets on the calendar month — on the 1st of each month, you get 5 new captures. You can check your remaining count in the popup.
Fix: The anonymize toggle only affects the generated prompt, not the stored capture. You can toggle it on/off and regenerate the prompt at any time.
- ⚠️ Capture mode: Use "Element" for specific UI components, "Viewport" for full-page captures, and "Region" for custom selections.
- ⚠️ Console errors: Only errors from the last 10 seconds before capture are included — this ensures you get relevant context, not a flood of old errors.
- ⚠️ Screenshot cropping: Works best on standard and retina displays. The crop math has been tested at both 1x and 2x scaling.
A Note on Accuracy
Component detection (React/Vue) is a best-effort heuristic — production/minified builds often strip the component names this relies on, so when the tool says "Not detected," it's being honest rather than showing a fabricated value. The selector, styles, and screenshot are always accurate.
Console error capture listens for window.onerror and unhandledrejection events. It does not intercept console.error() calls the page's own code makes intentionally — that would require running in the page's own JavaScript world, which this extension deliberately avoids for safety.
Screenshot cropping has been tested at both 1x and 2x/retina display scaling, and correctly handles elements that overflow the captured image bounds or are partially off-screen. The crop math is pixel-accurate.
Free-tier counter has been tested at under-limit, exactly-at-limit, Pro-unlimited, and a fresh new month — all correct. The limit resets on the 1st of each calendar month.
Frequently Asked Questions
Does this extension send my captured data anywhere?
No. All captured data stays locally in your browser. The only network calls this extension makes are an optional license check against Gumroad, and — only if you've added one — requests to your chosen AI provider using your own API key.
Why doesn't component detection work on some sites?
Production builds often strip component names to save bundle size. The extension uses a heuristic that works on development builds and some production builds, but when names are stripped, it can't recover them. The selector, styles, and screenshot are still captured correctly.
What happens when I reach the free tier limit?
The 6th capture in a calendar month shows an upgrade prompt. Pro gives you unlimited captures. The limit resets on the 1st of each month.
Can I use this with any AI coding assistant?
Yes — the generated prompt is plain text formatted with markdown-style sections. It works with Cursor, Claude Code, ChatGPT, GitHub Copilot, or any AI assistant that accepts text input. Optionally, you can connect your own Anthropic or OpenAI key to get responses directly inside the extension.
What happens if I uninstall the extension?
All data (captures, settings, history) is removed from your browser. If you have a Pro license, you can re-enter your key after reinstalling to restore access.
Ready to give your AI assistant perfect UI context?
Free forever: 5 captures/month · Pro: $5/mo or $30/yr · 14-day free trial
Get UI Context Capture Pro → Install Free on Chrome Web Store →UI Context Capture for AI Coders · Version 1.0 · Built with ❤️ for Chrome · Privacy Policy · Contact Me
