Fact Check & Privacy
Not everything AI tells you needs a fact-check. But some things absolutely do. Here's how to know the difference.
Anything you're about to act on
Anything health or medical
Legal and financial decisions
Specific numbers, dates, and statistics
Quotes from real people
Worth a Quick Look
Recent news and current events
Local businesses, hours, and prices
Lesser known people, places, or products
Industry specific or technical claims
Trust It & Move On
Brainstorming and idea generation
Summarizing content you provided
Explaining well known concepts
Formatting, rewriting, or reorganizing your own work
When wondering about AI privacy, ask yourself: would I be comfortable if this showed up somewhere unexpected? If not, leave it out.
Never Include This
Passwords or login credentials
Social Security or ID numbers
Credit card or banking information
Private medical records or diagnoses
Confidential work or client information
Include With Caution
Your full name combined with location or employer
Personal situations involving other people
Sensitive workplace issues or internal company details
Anything you wouldn't want your employer to read
Personal struggles or mental health information
Safe to Include
General questions and curiosity
Content you're drafting and will review
Publicly available information
Your professional role or general industry
Creative projects and personal ideas
Document Security
A black box is not redaction.
It's hiding in plain text.
Slapping a black rectangle over sensitive text looks right, but the original words often remain in the file — copy-paste-able, searchable, and discoverable. Here's what actual redaction requires.
Drawing or pasting a black shape over text in a PDF editor, Word doc, or image does not remove the underlying data. The text layer still exists. Anyone who knows how to select all, export, or run OCR gets it right back.
See the difference
How to redact in Preview
macOS's built-in PDF viewer has a real redaction tool — it permanently removes text, not just covers it. macOS only
Open your PDF in Preview
Right-click the file → Open With → Preview. Make sure you're not accidentally in Acrobat or another app.
Open the Markup toolbar
Click the pencil icon in the toolbar, or press ⇧⌘A. This reveals annotation and markup tools.
Select the Redact tool
In the Markup toolbar, click the Redact button (it looks like a black rectangle with an X). If you don't see it, go to Tools → Redact in the menu bar.
⚠️ This is different from the Rectangle Shape tool, which is the bad kind.Draw over the content to redact
Click and drag to select each piece of sensitive text or imagery. Repeat for every instance — you can make multiple selections before applying.
Preview will show a red overlay as a preview of what will be removed.
Apply the redaction
Click Apply in the banner that appears, or go to Tools → Apply Redactions. Preview will warn you that this is permanent. That's the point.
⚠️ You cannot undo after saving. Work on a copy, not your original.Save as a new file
Use File → Export as PDF to save the redacted version. Don't overwrite your original until you've verified the result looks right.
After you redact
A few habits that keep sensitive data actually gone.
🔍 Verify with copy-paste
Open the redacted file, try to select the blacked-out areas, and copy. If anything pastes, the redaction didn't work.
📄 Always work on a copy
Keep the original document untouched. Redaction is permanent — you want somewhere to go back to if you over-redact.
🖼️ Images need special attention
Text embedded inside an image (like a scanned form) isn't a text layer. You'll need to redact visually and flatten the file.
📋 Metadata too
PDFs carry metadata: author, creation date, edit history. Preview's Export doesn't strip all of it. For high-stakes docs, check with a dedicated tool.
Bottom line: If someone can select the text under your "redaction," it isn't redaction. Real redaction permanently removes the data from the file — not just from view. When in doubt, use the dedicated tool rather than a shape, annotation, or screenshot.