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Chrome extension — Sentinel BYO

Enrich Sentinel with the full content of your paid press subscriptions — Le Monde, FT, NYT, Politico and 13 more — without ever sending your credentials to our servers.

BYO security model

Chrome browser (your machine)

Authenticated session

Le Monde · FT · NYT · Politico · …

Sentinel BYO Extension

  1. 1.Polls the article queue (every 15 min)
  2. 2.Fetches the article using your local cookies
  3. 3.Extracts clean text from the DOM
  4. 4.Sends text to Sentinel (HTTPS)
HTTPS
structured text only

Never transmitted:

✗ Passwords

✗ Session cookies

✗ Credentials

Sentinel servers

Received & stored

✓ Article text

✓ user_id (audit trail)

Never received

✗ Passwords

✗ Third-party cookies

✗ Media sessions

1. Prerequisites

  • An active Sentinel account with a Firm or Enterprise plan.
  • Google Chrome version 88 or later.
  • Be logged into your press subscriptions on the relevant sites in Chrome (your usual session).
  • Leave Chrome open so the service worker can run in the background.

Required plan: Firm or Enterprise. API key creation returns a 402 error on Solo and Team plans. Contact your administrator to upgrade.

2. Install the extension (developer mode)

Chrome Web Store pending. While awaiting Google review, install the extension in developer mode from the ZIP file provided by Sentinel.

  1. In Sentinel, go to Settings → API Keys and click Download extension to get the ZIP file.
  2. Extract the ZIP into a permanent folder on your machine (e.g. ~/extensions/sentinel-byo/).
  3. In Chrome, open chrome://extensions/.
  4. Enable Developer mode (toggle in the top right corner of the page).
  5. Click Load unpacked and select the folder extracted in step 2.
  6. The Sentinel S icon appears in the Chrome toolbar.

Important: do not delete the extracted folder. Chrome loads the extension from this folder on every start.

3. Create your API key

The key is shown only once. Copy it immediately to a password manager. It cannot be retrieved later.

  1. In Sentinel, go to Settings → API Keys.
  2. Click + Create API key.
  3. Give it a meaningful name, e.g. Chrome Extension — Marc's workstation.
  4. Select the scope: extension.
  5. Click Create. The key in sk_live_xxxxx... format is displayed.
  6. Copy the key immediately — it will no longer be visible after closing this window.

Each user must generate their own key. This per-user model enables targeted revocation (if a workstation is lost, revoke only that key without affecting others) and maintains an audit trail per user_id.

4. Configure the extension

  1. Click the Sentinel S icon in the Chrome toolbar. The popup opens.
  2. Enter the Sentinel URL: https://app.sentinelbriefing.com (default value, do not change unless on-premises).
  3. Paste your sk_live_... key into the API Token field.
  4. Click Test auth. A green checkmark ✓ confirms the connection works.
  5. Check Enable automatic fetch.
  6. Click Save.

The extension is now active. It will poll Sentinel every 15 minutes to pick up queued articles.

Supported publishers

The extension can access the 17 publishers listed below. Publishers marked Specific have a dedicated DOM extractor (more reliable and complete extraction). Others use a generic extractor (<article> / <main>).

PublisherDomainCountryExtractor
Le Mondelemonde.fr🇫🇷Specific
Les Échoslesechos.fr🇫🇷Specific
Le Figarolefigaro.fr🇫🇷Specific
Mediapartmediapart.fr🇫🇷Specific
La Croixla-croix.com🇫🇷Generic
Libérationliberation.fr🇫🇷Generic
Le Parisienleparisien.fr🇫🇷Generic
Le Nouvel Obsnouvelobs.com🇫🇷Generic
Courrier Internationalcourrierinternational.com🇫🇷Generic
Le Monde Diplomatiquemonde-diplomatique.fr🇫🇷Generic
Le Grand Continentlegrandcontinent.eu🇪🇺Generic
Politico Europepolitico.eu🇪🇺Specific
Politico USpolitico.com🇺🇸Specific
Financial Timesft.com🇬🇧Specific
The New York Timesnytimes.com🇺🇸Specific
Foreign Affairsforeignaffairs.com🇺🇸Specific
LinkedInlinkedin.com🌐Content script

To add a domain not listed above, contact your Sentinel administrator. Adding a domain requires an extension update and reinstallation.

Polling behaviour

Poll intervalEvery 15 minutes
Articles per cycleMaximum 5 articles per cycle (MV3 service worker limit)
Delay between fetches8 seconds between fetches (to avoid overloading target sites)
RequirementChrome must be open. If Chrome is closed, fetches resume on next launch.
Token storagechrome.storage.local — encrypted at rest by Chrome.

Privacy & GDPR

The BYO model was designed from the ground up to never transmit your credentials to our servers. Here are the technical guarantees:

  • Credentials never transmitted: session cookies for media sites (Le Monde, FT, etc.) stay in your browser. Sentinel never sees them.
  • Text only: the extension extracts structured article text and sends it to Sentinel via HTTPS. No cookies, no session data.
  • Encrypted API token: your sk_live_... key is stored in chrome.storage.local, encrypted at rest by Chrome. It is transmitted only to app.sentinelbriefing.com.
  • Whitelisted domains: the extension can only access domains declared in manifest.json → host_permissions. All other domains are ignored.
  • Audit trail: each submission is traced with the user_id of the API key used, allowing the firm administrator to see which key submitted which content.
  • Targeted revocation: if a workstation is lost, its associated key can be revoked from Sentinel without affecting other users.

Troubleshooting

"Test auth" shows a red error

Check that the Sentinel URL is exactly https://app.sentinelbriefing.com (no trailing slash) and that the sk_live_... key is complete and has no spaces. If the key has been lost, create a new one from Settings → API Keys.

402 error when creating the API key

Your account is on the Solo or Team plan. The extension requires the Firm or Enterprise plan. Contact your administrator.

No articles appear in Sentinel

Check that (1) Chrome is open, (2) you are logged into your press subscription on the relevant site in Chrome, (3) "Enable automatic fetch" is checked in the popup. Wait for the next cycle (max 15 min) or reopen the popup and click "Save" to force a poll.

Articles arrive truncated or empty

The publisher has likely redesigned its DOM. The generic extractor tries to read <article> or <main> — if these tags have changed, extraction is partial. Report the issue to your Sentinel administrator.

The Sentinel icon does not appear in the toolbar

Go to chrome://extensions/ and check that the extension is enabled. If it is not listed, reload it (click "Load unpacked" and reselect the folder). Pin the icon via the Extensions menu (puzzle icon) → pin.

FAQ

Does Sentinel see my passwords?

No. Your credentials never leave your browser. The extension uses cookies already present in Chrome to access articles. Only the extracted text is sent to Sentinel, via HTTPS.

Does the extension work on Firefox?

Not yet. Firefox support (Manifest V2/V3 dual) is planned for a future version. Only Chrome is currently supported.

Can I revoke access for one workstation without affecting others?

Yes. Since each user has their own sk_live_... key, revoking one key only affects the associated workstation. Go to Settings → API Keys → Revoke.

What if I change computers?

Install the extension on the new machine (steps 1–4) and generate a new API key from Settings → API Keys. Revoke the old key if the old workstation is no longer in use.

Does the extension run when Chrome is closed?

No. The Manifest V3 service worker only runs when Chrome is open. If you close Chrome over the weekend, fetches resume automatically on the next Chrome launch.

The extension is open-source. Its source code can be audited by any user who wants to verify that no authentication data is sent to Sentinel.

Chrome extension, Sentinel Briefing Docs