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ContextMeter privacy policy

Last updated: 2026-10-08.

ContextMeter is a browser extension that estimates how full your AI chat's context window is. It is built to work entirely on your device.

What ContextMeter reads

When you open a chat on chatgpt.com or claude.ai, the extension reads the text of the messages shown on the page so it can estimate how many tokens the conversation uses. It does this inside your browser and only on those two sites.

What leaves your device

Nothing. ContextMeter has no server, no analytics, no telemetry, no accounts and makes no network requests of its own. Your chat text is never sent to us or to anyone else.

What is stored

On your device only (browser extension storage):

• Your settings (plan, limits, warning levels, theme, position, and whether you allowed automatic full-chat reading).
• The plan name shown in the ChatGPT sidebar (for example "Plus"), read from the page so the right limit is used. Your name and email are never read or stored.
• A list of recent chats with their title, estimated token count and time. Message text is not stored.
• After a full scan of a chat, per-message token counts together with the site's own opaque message ids (numbers and ids only, no text), kept for up to 40 chats so reopening a chat shows its exact count at once. You can clear them in Settings.
• If you use Handoff: a summary you asked the AI to write may be held briefly so it can be inserted into a new chat. It is held in extension storage and removed as soon as you insert or dismiss it. If you do neither, it expires after 10 minutes and is deleted the next time the browser starts, the extension wakes up, or you open a ChatGPT or Claude page. If you press Send in a new chat, that text then goes to the AI service as part of your own message, the same as anything you type.

You can clear the recent-chats list and reset settings at any time in the extension's settings page. Uninstalling the extension removes all of its stored data.

Reading whole chats

ChatGPT and Claude load long chats in pieces, so counting a whole chat means loading it. ContextMeter does this only if you allow it (it asks the first time, and you can turn it off at any time in the panel or in settings). While it reads, it scrolls the chat in your own tab, then puts you back where you were. Nothing is sent anywhere.

Permissions

• Access to chatgpt.com and claude.ai: to read the visible messages and show the meter.
• Storage: to keep your settings, the plan name and the remembered counts on your device.

No other permissions are requested.

Estimates, not guarantees

Token counts are estimates based on the text visible on the page. They exclude content the page does not show (system prompts, memory, tool output, hidden reasoning, attachments) and may be wrong. Do not rely on them for billing or safety decisions.

Children

ContextMeter is not directed at children and collects no personal information.

Changes

If this policy changes, the new version will be published with the extension and the date above updated.

Contact

Questions about this policy: support@contextmeter.app.