Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of Slant Detective

Slant Detective by Rabbit Factory

See how any news article is slanted — the lean, the loaded words, the phrases doing the work. In the article itself.

0 (0 reviews)0 (0 reviews)
Download Firefox and get the extension
Download file

Extension Metadata

Screenshots
NYT analysis with keyBreitbert Analysis with keyHow we measureKey insertion
About this extension
See how any news article is slanted — right in the article itself.

Click the Slant Detective icon on any news page and a sidebar opens with a structured readout: the overall lean, the loaded words, and the specific phrases doing the persuading. Every flagged phrase is underlined in the article so you can see the evidence in context.

No account. No server. Your article never leaves your browser unless you choose to run in-depth analysis with your own API key — and then it goes straight to your chosen provider.

────────────────────────

FREE — instant, no setup, no key required
An entirely in-browser analysis:
• A 2,100-word bias lexicon from peer-reviewed research (BABE)
• Attribution-verb skew ("said" vs. "alleged" vs. "admitted")
• Headline-vs-body drift
• Hedge-word count
• An outlet-level lean label (e.g. "Lean Left," "Center")

IN-DEPTH ANALYSIS — paste your own API key
Paste a key from Anthropic, OpenAI, or Google and unlock:
• An overall intensity score and direction
• A four-dimension breakdown (word choice, framing, headline, source mix)
• Evidence phrases with a one-sentence reason for each
• Dotted underlines on the actual biased phrases in the article
• Hover for the reason, click to scroll to the phrase

Your key stays in your browser. The call goes from your browser straight to your provider. We never see the article or the key.

────────────────────────

FIRST-TIME SETUP ON FIREFOX
If the Slant Detective icon isn't visible after install, right-click the toolbar, choose "Customize Toolbar," and drag the icon onto the bar. Click it on any news article to toggle the sidebar.

Note: Firefox's sidebar is global (one instance across all tabs), not per-tab. When you switch tabs, Slant Detective re-runs against the new article automatically.

────────────────────────

COST
Free tier is free forever. In-depth analysis uses your own API key, and you choose the provider: Gemini 2.5 Flash runs about $0.0002 per article — well under $1/month for a typical reader. Claude Haiku runs about $0.0018 per article — roughly $1–3/month. OpenAI GPT-5-mini sits in between. You pay your provider directly — we take no cut.

OPEN SOURCE
Full source, the bias-word lexicon, and the outlet-label dataset are all AGPL-3.0 on GitHub. You can verify exactly what data leaves your device and where it goes. We run no backend. No account database. No advertising.

────────────────────────

WHAT'S NEW IN v1.1
• Choose your provider: Anthropic, OpenAI, or Google Gemini
• Percentile context — see how the article's score compares to other news domains
• Dotted underlines on biased phrases, right in the article
• Hover tooltips with category and reason
• Works on AMP pages and JS-hydrated sites (NYT, Breitbart, and more)
• Info-icon explanations on every dimension label
• Plain-English rationale on the signal summary
Rated 0 by 0 reviewers
Log in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and data

Required permissions:

  • Access browser tabs
  • Access your data for all websites

Optional permissions:

  • Access your data for api.anthropic.com
  • Access your data for api.openai.com
  • Access your data for generativelanguage.googleapis.com
  • Access your data for sd-telemetry.rabbit-factory.workers.dev

Required data collection, according to the developer:

  • Website content

Optional data collection, according to the developer:

  • Technical and interaction data
Learn more
More information
Add-on Links
  • Support Email
Version
1.1
Size
24.24 MB
Last updated
9 days ago (Apr 24, 2026)
Related Categories
  • Feeds, News & Blogging
License
GNU Affero General Public License v3.0 only
Privacy Policy
Read the privacy policy for this add-on
Version History
  • See all versions
Add to collection
Report this add-on
Go to Mozilla's homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Browsers

  • Desktop
  • Mobile
  • Enterprise

Products

  • Browsers
  • VPN
  • Relay
  • Monitor
  • Pocket
  • Bluesky (@firefox.com)
  • Instagram (Firefox)
  • YouTube (firefoxchannel)
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike License v3.0 or any later version.