An AI-powered Firefox extension that lets you ask questions about any web page, get summaries, and fill forms — all powered by Anthropic Claude.
- 🔍 Ask questions about any web page in natural language
- 📝 Page summarization — get a quick overview of long articles or documents
- 📋 Form filling assistance — describe what you want, review AI suggestions, then confirm
- 🤖 Anthropic Claude integration — powered by Claude Sonnet 4, Opus 4, and Haiku 4
- 🔗 Custom base URL support — route API calls through your own proxy or gateway
- 💬 Per-tab conversation history — each browser tab maintains its own chat context
- Firefox 57+ (Quantum or later)
- An Anthropic API key — get one at console.anthropic.com
Temporary extensions are removed when Firefox restarts. Use this for testing.
- Open Firefox and navigate to
about:debugging - Click This Firefox in the left sidebar
- Click Load Temporary Add-on…
- Browse to the project folder and select
src/manifest.json - The extension icon appears in the toolbar
- Pack the
src/directory into a.zipfile, then rename it to.xpi - Open Firefox and navigate to
about:addons - Click the ⚙️ gear icon → Install Add-on From File…
- Select your
.xpifile - Accept the permissions prompt
Note: Unsigned extensions require Firefox Developer Edition or Nightly with
xpinstall.signatures.requiredset tofalseinabout:config.
Visit console.anthropic.com, sign in or create an account, and generate an API key under API Keys.
-
Click the PageMind toolbar icon
-
Click the ⚙️ Settings button inside the popup
or
-
Navigate to
about:addons→ find PageMind → click Preferences
| Field | What to Enter |
|---|---|
| API Key | Paste your Anthropic API key (starts with sk-ant-…) |
| Model | Select a Claude model from the dropdown |
| Base URL | Leave blank for default, or enter your proxy URL |
Click Save Settings. A confirmation message confirms the key was stored.
- Navigate to any web page
- Click the PageMind toolbar icon
- Type your question in the input box (e.g., "What is the main topic of this article?")
- Press Enter or click Send
- The AI response appears in the chat area
In the input box, type a summarization request:
Summarize this page in 3 bullet points.
PageMind can detect form fields on the page and suggest values.
- Navigate to a page with a form
- Open the popup and describe what to fill in:
Fill in the contact form with my name John Doe and email john@example.com - The AI analyzes the form and proposes field values
- Review the suggestions shown in the popup
- Click Confirm & Fill to apply them — or Cancel to discard
⚠️ Form values are never submitted automatically. You always review and confirm before anything is written to the page.
Click the 🗑 Clear button in the popup to reset the conversation for the current tab. This does not affect other tabs.
| Action | Shortcut |
|---|---|
| Send message | Enter |
| New line in input | Shift + Enter |
All settings are saved in Firefox's storage.sync and synced across devices when signed into Firefox Sync.
| Setting | Required | Default | Description |
|---|---|---|---|
apiKey |
✅ Yes | (empty) | Your Anthropic API key |
baseUrl |
No | https://api.anthropic.com |
API endpoint; change for proxy use |
model |
No | claude-sonnet-4-20250514 |
Claude model to use |
maxContentLength |
No | 100000 |
Max characters of page content sent per request |
maxConversationPairs |
No | 10 |
Max message pairs retained in history |
firefoxextension/
├── src/
│ ├── manifest.json # Extension manifest (MV2)
│ ├── background/
│ │ ├── api-client.js # Anthropic API communication
│ │ └── background.js # Service worker / message router
│ ├── content/
│ │ ├── content.js # Page content extraction
│ │ └── form-filler.js # Form field detection & filling
│ ├── popup/
│ │ ├── popup.html # Popup markup
│ │ ├── popup.css # Popup styles
│ │ ├── popup.js # Popup entry point
│ │ └── popup-ui.js # UI state management
│ ├── options/
│ │ ├── options.html # Settings page markup
│ │ ├── options.css # Settings styles
│ │ └── options.js # Settings logic
│ ├── shared/
│ │ ├── constants.js # Global constants & defaults
│ │ ├── message-types.js # Message type definitions
│ │ ├── storage.js # Storage abstraction
│ │ └── validators.js # Input validation helpers
│ └── icons/ # Extension icons (16/32/48/128px)
├── tests/
│ ├── package.json # Test dependencies (Jest)
│ ├── setup.js # Jest global setup
│ ├── load-source.js # Source loader for IIFE modules
│ ├── background/ # API client tests
│ ├── content/ # Form filler tests
│ ├── popup/ # Popup UI tests
│ └── shared/ # Shared module tests
├── docs/ # Architecture, spec, and phase docs
└── scripts/
└── generate-icons.js # Icon generation helper
cd tests
npm install
npm testTests are written with Jest and cover all shared modules, the API client, form filler, and popup UI logic.
See docs/CONTRIBUTING.md for development setup, code style, and the pull request process.
- API keys are stored using Firefox's encrypted
storage.syncAPI — never in plain text, localStorage, or cookies - API calls are made exclusively from the background script — the key is never exposed to content scripts or the page DOM
- The extension's Content Security Policy (
script-src 'self') blocks inline scripts and external script injection - Form filling requires explicit user confirmation before any value is written to the page
For a full audit, see docs/security-review.md.
When you ask a question, the following data is sent to Anthropic's API:
- The text content of the current web page (up to
maxContentLengthcharacters) - Your question and prior conversation history for the current tab
No data is sent to any third party other than Anthropic (or your configured proxy). No browsing history, cookies, or credentials are ever transmitted.
Review Anthropic's Privacy Policy for details on how they handle API data.