Silent Send

A browser extension (Chrome + Firefox) that intercepts personal information and substitutes it with user-defined replacements before sending to AI services.

Supported services

Service	Domains	Status
Claude	claude.ai, claude.ai/code	Tested
ChatGPT	chatgpt.com, chat.openai.com	Untested
Grok	grok.x.ai, x.com/i/grok	Untested
Gemini	gemini.google.com	Untested
OpenWebUI	localhost, 127.0.0.1 (self-hosted)	Untested

Note: Only Claude has been tested so far. The other services have API interception patterns defined but may need adjustments. PRs welcome.

How it works

1. You fill in your Identity — name, email, username, computer name, phone
2. Smart patterns auto-catch variations — jsmith@macbook-pro, John's, /home/jsmith, 555.123.4567
3. You type normally — you see your real text while composing
4. On send, it swaps — the extension intercepts the API request and replaces real values with substitutes
5. Badge shows count — the extension icon shows how many substitutions were made
6. Reveal mode — optionally translates Claude's responses back to your real data

Smart pattern examples

You type	What gets sent
jsmith@macbook-pro	ademo@mycomputer
anyone@gmail.com	anon@example.com (catch-all)
John Smith	Alex Demo
Smith, John	Demo, Alex
John's code	Alex's code
/home/jsmith/project	/home/ademo/project
~jsmith	~ademo
C:\Users\jsmith	C:\Users\ademo
(555) 123-4567	(555) 000-0000
555.123.4567	(555) 000-0000
macbook-pro	mycomputer

How to verify it's working

• Badge count on the extension icon shows substitutions per page
• Activity tab in the popup shows a timestamped log of every substitution
• Test tab in the popup lets you type text and see the before/after diff live
• Reveal mode (eye icon) toggles showing real vs substitute data in responses
• Browser DevTools → Console shows [Silent Send] Substituted N value(s) messages

Installation

Prerequisites

You need Git and Node.js (v18+) installed.

Clone the repo:

git clone https://github.com/outis1one/silent-send.git
cd silent-send

Chrome (Developer Mode)

1. Run ./build.sh chrome (or just use the root directory directly)
2. Open chrome://extensions/ in your browser
3. Enable Developer mode (toggle in the top right corner)
4. Click Load unpacked → navigate to and select the dist/chrome/ folder (or the repo root)
5. Navigate to any supported AI site — the extension icon appears in your toolbar

That's it for Chrome. No account, no store, no fees.

Firefox (signed, persistent)

Firefox requires extensions to be cryptographically signed before it will install them permanently. Mozilla provides free self-hosted signing — no store listing, no review process, no fees.

Step 1: Create a free Firefox account

1. Go to https://accounts.firefox.com/ and create an account (or sign in if you have one)
2. This is the same account used for Firefox Sync — you may already have one

Step 2: Get your Mozilla API credentials

1. Go to https://addons.mozilla.org/developers/addon/api/key/
2. Sign in with your Firefox account from step 1
3. On that page you'll see two values:
   • JWT issuer — this is your API key, looks like user:12345678:901
   • JWT secret — a long alphanumeric string, this is your API secret
4. Keep this page open — you'll need both values in the next step

Step 3: Configure your credentials

# Install dependencies
npm install

# Copy the env template
cp .env.example .env

Now open .env in any text editor and paste in your values from step 2:

WEB_EXT_API_KEY="user:12345678:901"
WEB_EXT_API_SECRET="your-jwt-secret-here"

Save the file.

Step 4: Build and sign

source .env && npm run sign:firefox

This builds the Firefox version and submits it to Mozilla for signing. It takes 10-30 seconds. When done, you'll see a signed .xpi file in dist/firefox-signed/.

Step 5: Install the signed extension

• Drag the .xpi file into any Firefox window, or
• Firefox menu → File → Open File → select the .xpi
• Click Add when prompted

The signed .xpi is permanent — it survives browser restarts, updates, everything. No store listing, no review process, no fees. You only need to re-sign when you update to a new version.

Firefox (temporary, for development)

If you just want to try it out without signing:

npm install && npm run run:firefox

This opens a fresh Firefox with the extension pre-loaded. Auto-reloads on file changes. Resets when Firefox closes — useful for testing, not for daily use.

Architecture

manifest.json           — Chrome extension manifest (Manifest V3)
manifest.firefox.json   — Firefox variant (adds gecko ID for signing)
build.sh                — Copies the right manifest to dist/{chrome,firefox}/
src/
  background/
    service-worker.js   — Badge management, logging coordination
  content/
    injector.js         — Content script (isolated world) — loads config, bridges messaging
    content.js          — Page script (main world) — hooks fetch(), does substitution
    content.css         — Visual indicators (highlights, reveals)
  popup/
    popup.html/css/js   — Quick access: identity, mappings, activity, test mode
  options/
    options.html/css/js — Full mapping management, import/export, settings
  lib/
    substitution-engine.js — Core explicit find/replace logic
    smart-patterns.js   — Auto-detection of emails, names, usernames, hostnames, phones, paths
    storage.js          — Browser storage wrapper
    browser-polyfill.js — Chrome/Firefox API compatibility

Privacy

• All data stays local in browser storage
• No external servers, no telemetry, no analytics
• The extension only activates on claude.ai
• Your real identity data never leaves your machine