Browser Extension¶
The Gobbler browser extension enables bidirectional communication between Gobbler and your browser, allowing extraction of authenticated content and browser automation.
Features¶
- Extract current page content (works with authenticated sessions)
- Extract with CSS selectors
- Navigate pages programmatically
- Execute JavaScript in browser tabs
- Control AI chat interfaces (NotebookLM, Claude.ai, ChatGPT, Gemini)
Installation¶
1. Load Extension in Chrome¶
- Open Chrome and go to
chrome://extensions/ - Enable Developer mode (toggle in top right)
- Click Load unpacked
- Select the
browser-extensiondirectory from the Gobbler repo
2. Create Gobbler Tab Group¶
- Right-click any tab you want to control
- Select Add to group → New group
- Name the group exactly "Gobbler"
Only tabs in the "Gobbler" group can be controlled by Gobbler (security feature).
3. Verify Connection¶
Should show: 1 browser extension(s) connected
How It Works¶
Your Browser (with real sessions)
↓
Gobbler Extension (extracts HTML)
↓
WebSocket to Relay Server (localhost:4625)
↓
Gobbler CLI / MCP Server
↓
Response with markdown
Advantages¶
- Uses your real browser session (no cookie copying)
- No bot detection (it's your actual browser)
- Works with 2FA, private content, etc.
- Full JavaScript execution capability
Security Model¶
Tab Group Isolation: Only tabs in the "Gobbler" tab group are accessible. This prevents accidental access to sensitive tabs (banking, email, etc.).
To add a tab to the group: 1. Right-click the tab 2. Select "Add to group" → "Gobbler"
To remove a tab: 1. Right-click the tab 2. Select "Remove from group"
CLI Commands¶
Check Status¶
List Controlled Tabs¶
gobbler browser list
# Filter by page type
gobbler browser list --filter notebooklm
gobbler browser list --filter claude
# JSON output for scripting
gobbler browser list --json
Open URLs in Gobbler Tab Group¶
# Open URLs in Gobbler tab group
gobbler browser open "https://example.com"
gobbler browser open "url1" "url2" "url3"
Extract Page¶
# Full page
gobbler browser extract -o page.md
# With selector (experimental)
gobbler browser extract --selector "article.content" -o article.md
Navigate¶
Execute JavaScript¶
Troubleshooting¶
Extension won't load¶
- Make sure icon files exist in
icons/directory - Check Chrome extension errors at
chrome://extensions/
"No browser extension connected"¶
- Verify extension is installed and enabled
- Check extension popup shows "Connected"
- Restart the relay:
gobbler relay restart
"No tabs found"¶
- Open the page you want to control
- Right-click tab → "Add to group" → "Gobbler"
- Run
gobbler browser list
Commands timeout¶
- Increase timeout:
--timeout 60 - Check browser tab is active
- Verify page has loaded completely
Development¶
The extension consists of:
| File | Purpose |
|---|---|
manifest.json | Extension configuration |
popup.html/js | Extension popup UI |
content.js | Content script for page interaction |
background.js | Service worker for WebSocket |
page-apis/*.js | Site-specific APIs (NotebookLM, Claude, etc.) |
Future Features¶
- [ ] Batch extraction (multiple tabs)
- [ ] Auto-extract on page load
- [ ] Save extractions to files
- [ ] Custom extraction templates