Privacy and sensitive sources

The policy itself is PRIVACY.md. This page explains the rules and how the code enforces them.

What leaves your computer

Only the request you trigger: when you ask for an explanation or a follow-up, the model service you configured receives

• the selected text (at most 200 characters),
• its paragraph (at most 2,000 characters, centred on the selection),
• the section heading and the page title,
• the first sentence of the abstract,
• the names of up to three of your earlier concepts that look like the term, and whether you understood them,
• for Compare: the earlier quote, source title and explanation,
• for a follow-up: your question and the earlier explanation,
• for Check my answer in review (only when you press it, and it can be turned off in settings): the term, what you typed, and the stored explanation. The same model and sensitive-source rules apply, and each check counts against your rate limit. The check itself is not saved; only the grade you pick afterwards is.

Nothing else is sent: not the rest of the page, not your history, not your other settings. There is no analytics and no developer server.

Page text and earlier explanations are placed inside delimiters, and the model is told not to follow instructions found in them. The reply is parsed defensively and shown as text or through a restricted Markdown renderer; it is never inserted as HTML.

Sensitive sources

Mark a source sensitive when its content must not leave your computer.

• On the explain card: Mark source as sensitive.
• In settings: tick Sensitive on a site rule.

For sensitive material:

• the request goes only to the model ticked Sensitive provider, which must be local (127.0.0.1, localhost, [::1]). A server on your own network does not qualify. With no such model, the explanation fails with a message instead of falling back to a remote one;
• earlier concepts known only from sensitive sources are not listed to a remote model, even for a different, normal page;
• Compare refuses to send a sensitive earlier record to a remote model;
• records are still kept in your browser, and the history shows a Sensitive source badge.

Sensitivity is sticky. Once a source is sensitive, only your own choice (Mark as normal on its history entry) makes it normal again: an automatic record from elsewhere, such as a backup restored from a device that never knew, cannot undo it.

A site rule that matches a source applies even to records made before the rule existed. Rules can be switched off for a more specific path; see Site rules.

Pages that look private

Most pages on GitHub, Notion and Google Docs are private, and a page looks the same to Harkback whether or not you may share it. So it goes by hints and asks when it is unsure, before anything is sent:

• a GitHub page that says its repository is private, and a Notion or Google Docs page that is not published, are held back until you choose Local only (the source becomes sensitive) or Send anyway (the usual model);
• a published page (*.notion.site, a Google document's published link) is not held back;
• your choice is recorded as your own and can be remembered for the whole site as a rule; a rule for a site never silently hides a page that says it is private;
• in a private window the choice is not recorded and holds until you close or reload the page;
• the check happens in the background worker, in the same place that picks the model, so the page cannot skip it. The toolbar's page preview shows the same question before it offers to scan; underlining terms you know uses no model and never asks.

A hint can be wrong or missing, for example after a site changes its layout. Mark a site or path Sensitive when the content must never leave your computer; that is always followed and needs no hint.

An issue or pull request is as sensitive as its repository. Saying that one issue is fine overrides that for it alone, unless the repository is marked sensitive again afterwards.

Private windows

Incognito windows must be allowed for the extension in Chrome. In them Harkback explains but never records, scans or shows reunions, and every write request is refused.

Where your data is

Leave sensitive sources out of backups and exports (settings → Backup) removes everything that came from sensitive sources, and concepts known only from them, from backups, Markdown, notes and Anki files.

Limits to know about

• Reunion underlines live in the page, so the page's own scripts may infer which terms you have records for.
• Deletion removes an entry in the app and clears its text from the stored log; traces may remain on disk, and exported backups cannot be recalled. Use full-disk encryption.
• Keys are unencrypted in extension storage.
• The model service's terms apply to what you send it. A local model keeps even that on your computer.