Browser Extension

What it does

Two independent capabilities, both running locally in Chrome:

1. PII Masking (always on)

As you type in any AI chat box on claude.ai, chatgpt.com, Gemini, Perplexity, or DeepSeek, Omna watches for personal information:

• Names, emails, phone numbers, addresses
• ID numbers, passport numbers, driver's license numbers
• Credit card numbers, bank accounts, IBAN numbers
• Healthcare data, salary information, credentials and API keys

When PII is detected, it is replaced with a placeholder ([PERSON_1], [EMAIL_1], etc.) before the text leaves your browser. The AI sees the placeholder. Omna keeps a local registry that maps each placeholder back to the real value so results stay readable.

Shield mode: When Shield is ON, if the AI responds with [PERSON_1] in its answer, Omna swaps it back to the real name before it reaches your screen. The AI never knew the name; you see the name. Shield is off by default — turn it on in the extension popup.

Wire-level interception: Masking happens at the network level (the fetch call), not at the UI level. This means it works even on sites that use complex web frameworks, shadow DOM, or unconventional input patterns. The text is masked before the HTTP request is sent.

2. File Slicing (on AI attachment)

When you attach a file to an AI site's upload button, Omna intercepts it before the site sees it:

1. You click the attachment button and select your CSV, Excel, PDF, or Word file.
2. Omna captures the file at the browser level before it's submitted.
3. The extension sends the file to the Mac app (running in the background) for slicing.
4. The Mac app slices the file using your previously typed question as the search query.
5. The sliced file is swapped in — the AI site receives the sliced version, never the original.
6. A result banner appears above the chat composer showing how many tokens were cut.

Zero extra clicks. You attach a file the same way you always did. Omna's interception is invisible.

Supported sites for file slicing

The extension popup

Click the Omna icon in your Chrome toolbar to open the popup:

• Token savings: how many tokens Omna has trimmed in this browser session and roughly what that's saved in API cost
• Compression ratio: percentage reduction — e.g., "77% compression" means you sent 23% of the original tokens
• Fields masked: how many PII fields the native slicer has masked across file attachments this session
• Claim your spot: enter your email to reserve free Omna access during early access (first 10,000 users)
• Settings (gear icon): - Protection: Auto-mask PII in chat, Scrub PII from files, Shield mode - File Handling: Choose between Slice mode and Advisory mode (see below)

Slice mode vs Advisory mode

Open the popup → gear icon → File Handling to choose how Omna handles file attachments.

Slice mode (default): Omna intercepts the file, finds only the rows relevant to your question, masks any PII, and swaps in a smaller "surgical copy." The AI sees the slice — never the full file. A result card shows rows sent, token reduction, and how many fields were masked.

Advisory mode: Omna does not slice the file. The original goes through unchanged. Omna only runs its local PII scanner — if sensitive data is found, a warning banner appears before you send. Use this mode when you want to send the full file but still want a heads-up about sensitive content.

The toggle takes effect immediately — no page reload needed.

Does the extension work without the Mac app?

PII masking works without the Mac app. The masking engine runs as WebAssembly directly in Chrome — no network calls, no Mac app required.

File slicing requires the Mac app. The extension sends the file to the Mac app via Chrome's Native Messaging protocol (a secure, local-only channel). If the Mac app isn't running, the extension releases the file normally and shows a brief message: "Omna is not running — file sent without slicing."

What the result banner shows

After a successful slice, a banner appears above the AI chat composer:

• Token Tax killed (green): file was within Claude's context window; Omna sent a small relevant slice — real savings
• Token Tax crushed (green): file was too big for Claude's window; Omna's slice fits cleanly under the limit
• Token Tax redirected (amber): even Omna's slice fills the window — same token cost, but the right rows are in that window instead of arbitrary ones
• All rows matched (blue): your question matched every row in the file — nothing was filtered out, shown for transparency. (If even one row was dropped, the scenario is "Token Tax killed" instead.)

The banner shows: rows sent vs. total rows, token reduction percentage, estimated dollar savings, and — when new PII fields were masked during slicing — an amber "N items masked" chip. It disappears after a few seconds or when you click the × button.

Privacy

Everything happens locally:

• The masking engine runs as WebAssembly in Chrome — no server involved
• File slicing goes Mac app → sliced file → AI site (the original file never leaves your machine)
• No analytics, no telemetry, no data collection
• PII placeholders and the registry mapping them back to real values are stored in session memory only — they clear when you close the tab or the browser