Privacy Policy
Effective date: 30 April 2026 · Last updated: 30 April 2026
This is the privacy policy for the Four Line browser extension ("Four Line", "the extension", "we", "us"). Four Line is a new-tab-page extension that lets you open multiple AI services side by side and keep a personal library of prompts and notes.
We have written this policy in plain language. There is no surprising clause hidden later. The summary at the top is the whole story.
Summary
Four Line does not collect, transmit, store, or sell any personal data.
Four Line does not use analytics, tracking, telemetry, or advertising of any kind.
Four Line has no server. There is nowhere for your data to go.
Everything you do — your tabs, groups, prompts, notes — is stored only in your own browser, on your own device.
When you use an AI service through Four Line, you are interacting with that service directly. Their privacy policy applies, not ours.
That is the entire privacy story. The rest of this document explains it in more detail because the Chrome Web Store requires it.
What Data We Process
The extension processes the following information locally, in your browser, in order to function:
Workspace state. The list of AI services you have added, the groups you have arranged them into, which group is active, which tab is focused, your theme preference, and your sidebar position. This is stored in browser localStorage on your device.
Prompt library. Prompts you save (title and body) are stored in browser localStorage on your device.
Notes library. Notes you write (title, rich-text body, project assignment, timestamps) are stored in browser localStorage on your device. If you paste or upload an image into a note, the image is embedded as a base64 data URL inside that note's body — it never leaves your device.
Per-tab URL. The current URL of each AI service pane is saved alongside the tab so the extension can reopen the pane on the same page next time. This is also stored in browser localStorage on your device.
Pending captures. When you right-click a selection on any webpage and choose "Save to Four Line as Prompt" or "Save to Four Line as Note", the highlighted text and the title you provide are queued in chrome.storage.local on your device until your Four Line tab is open and can move the item into your library. The queue is then cleared.
None of these items are sent off your device by Four Line. We do not have a server. We do not contact any external service. We do not have any way to read your data even if we wanted to.
What We Do Not Do
We do not run analytics, tracking pixels, or telemetry.
We do not use cookies set by Four Line itself (the AI services have their own cookies; those are not ours).
We do not show ads.
We do not sell, rent, or share data, because we do not have any.
We do not have user accounts. There is nothing to sign up for.
We do not transmit your prompts, your notes, your conversation history, or any other workspace content anywhere.
We do not log your AI conversations or read what the AI sends back to you.
We do not collect device identifiers, IP addresses, browser fingerprints, or any other identifier.
Permissions We Request And Why
The Chrome Web Store lists the permissions Four Line uses. Each one is required for a specific feature, used only on the listed AI service domains, and never used to collect data about you.
declarativeNetRequest and declarativeNetRequestWithHostAccess Four Line removes the X-Frame-Options and Content-Security-Policy frame-ancestors response headers on the AI service domains so they will render inside the extension's split-view iframes. Without this, the side-by-side workspace would be impossible. We do not read, log, or modify your network traffic in any other way.
webNavigation Used to detect when you navigate inside an embedded AI service (for example, opening a saved Claude conversation or switching a Gemini account to /u/2). We use this only to remember the URL of each pane locally so the workspace restores it on next launch.
contextMenus Adds the "Save to Four Line as Prompt" and "Save to Four Line as Note" right-click items. They only do anything when you click them.
storage Persists your workspace, prompt library, and notes library on your device. Without this you would lose your setup every time you closed the browser.
activeTab and scripting Used so that when you right-click a text selection and choose to save it, Four Line can ask you for a title via a small dialog inside the tab where you right-clicked. activeTab grants temporary access only on that one tab, only at the moment you invoked the menu. We use scripting only to call window.prompt() for the title. No remote code is loaded or executed.
Host permissions for the AI service domains Required for the four reasons above (header rules, content scripts, navigation tracking) to apply on the right pages. We list each AI service domain explicitly and do not request a wildcard "all sites" permission.
Content Scripts We Inject Into Ai Service Pages
Four Line injects four small scripts into the AI service pages it embeds. They run only on those domains, never on other websites.
anti-framebusting. Stops AI sites from detecting that they are inside an iframe and refusing to render. Reads no user data.
url-tracker. Detects in-page URL changes (single-page-app navigation) so Four Line can remember which Claude/Gemini/etc. page you were on. The URL is sent to the extension's own background process and saved locally. Nothing is transmitted off the device.
broadcast-receiver. Listens for a "broadcast prompt" message from the Four Line workspace and types that prompt into the AI service's input field. Active only when you press the broadcast Send button. The text it injects is the text you typed into the broadcast bar — Four Line does not read or extract anything from the AI page itself.
selection-saver. Provides a small floating "Save as Prompt / Save as Note" toolbar when you select text inside an AI pane. The selected text is captured only when you click one of those buttons, and only with a title you confirm.
Third-Party Ai Services
Four Line is a workspace that embeds AI services. When you log in to ChatGPT, Claude, Gemini, Grok, Kimi, AI Studio, or any other site you add, you are interacting directly with that service over a normal HTTPS connection. Their privacy policies and terms apply to that interaction. Four Line has no visibility into the content of those conversations, and we have no business relationship with these providers.
Links to the privacy policies of the default AI services we ship with:
ChatGPT (OpenAI): https://openai.com/policies/privacy-policy
Claude (Anthropic): https://www.anthropic.com/legal/privacy
Gemini and AI Studio (Google): https://policies.google.com/privacy
Grok (xAI): https://x.ai/legal/privacy-policy
Kimi (Moonshot AI): https://kimi.com/privacy
Children
Four Line is not directed at children under 13 and we do not knowingly collect data from anyone — adult or child — because we do not collect data at all. The AI services Four Line embeds may have their own age policies; please check theirs.
Changes To This Policy
If we update this policy we will update the "Last updated" date above and publish the new version at the same URL where you are reading this one. Material changes will also be noted in the Chrome Web Store update notes for the version that introduces them.
Data Export, Deletion, And Control
Because all data is local, you control it directly:
To export your workspace, open Four Line, go to Settings, and use the Export button. You will receive a JSON file containing your tabs, groups, prompts, and notes.
To delete all Four Line data, open Settings and use the Reset button, or remove the extension from chrome://extensions. Either action erases everything Four Line has stored in your browser.
To delete data held by an AI service (your conversation history, account information, etc.), use that service's own settings page. Four Line cannot delete data on third-party servers.
Contact
Questions, concerns, or requests:
GitHub issues: https://github.com/<your-org>/fourline/issues
Email: <your-contact-email>
We aim to respond within 14 days.