How often do you spot manipulation in the videos you watch?

Propaganda techniques are hard to detect in real time. MediaGuard detects them as you watch — SponsorBlock-style segment markers and contextual overlays on YouTube.

Open source. Your key, your data.

How it works

1

Open any YouTube video

Navigate to any video on youtube.com.

2

Analysis loads

MediaGuard fetches the transcript (or captures tab audio if no captions). Mistral analyzes for manipulation techniques.

3

Segment markers appear

Colored bars on the progress bar: orange = manipulation, blue = fact-check claim.

4

Hover or play into a segment

A floating panel shows the technique name, quoted excerpt, and explanation.

Screenshots

Features

Non-intrusive UX

SponsorBlock-style segment markers on the timeline plus a contextual overlay when playback enters a manipulation segment.

Crowdsourced improvement

Add context to segments; Mistral augments annotations for future viewers.

Privacy-conscious

STT realtime — Transcribe tab audio in real time with ElevenLabs or Mistral Voxtral. Your API keys never leave your device.

14 techniques

Academic taxonomy from PRTA, SemEval-2020 Task 11, and PropaInsight (COLING 2025). Vote on annotations.

Techniques we detect

MediaGuard identifies 14 rhetorical manipulation techniques. Here's what the floating panel shows when you hover or play into a segment:

Appeal to Authority

Using experts, institutions, or credible-seeming persons to lend weight to a claim.

"Dr. Smith, a renowned epidemiologist from Harvard, stated that the vaccine is completely safe."

Loaded Language

Using words with strong emotional connotations to influence perception. Slanted vocabulary that triggers emotional responses.

"The brutal regime cracked down on protesters."

Appeal to Fear/Prejudice

Using fear, prejudice, or other strong emotions to influence the audience. Includes dramatic descriptions, catastrophic scenarios, or implicit threats.

"If we don't act now, economic collapse is imminent. Millions will lose their jobs."

Black-and-White Fallacy

Presenting two alternatives as the only possibilities when more options exist. False dilemma or false binary.

"You are either with us or against us. There is no middle ground."

Bandwagon, Reductio ad Hitlerum

Bandwagon: suggesting everyone supports a position. Reductio: comparing something to Hitler or Nazism to discredit it.

"Polls show 90% of Americans support this policy. Join the majority."

Research-backed

PRTA (ACL 2020) SemEval-2020 Task 11 PropaInsight (COLING 2025)
64.2% Span F1
70.0% LLM Judge

Built on academic definitions and benchmarked on a 50-item gold-annotated evaluation set.

Read methodology →

Videos without captions?

Use the STT app to capture tab audio, transcribe in real time (ElevenLabs or Mistral Voxtral), then send to MediaGuard for analysis. You can also add context to segments — Mistral augments annotations for future viewers.

Install

Requires a Mistral API key (free tier available). Your key is used only on your device.

Or load unpacked from the extension folder for development.