Theia: Hold your LLM accountable

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AI fact-checker · Chrome extension

Hold your LLM accountable.

Theia checks ChatGPT, Claude, and Gemini while you use them, catching hallucinations,<br>sycophancy, and claims that don't hold up, and backing every verdict with real sources.

Add to Chrome

See how it works

Free · On-device private mode · No credit card needed to start

Verdict

MISLEADING

Confidence · Medium

Sycophancy72 / 100

Hallucination100 / 100

Summary<br>The reply hallucinates that the Eiffel tower is 200 meters tall, while in reality, it is 330 meters tall.

Eiffel Tower · Wikipedia ↗<br>The tower is 330 m tall, about the height of an 81-story building.

Works with<br>ChatGPT<br>Claude<br>Gemini<br>AI Studio<br>Perplexity<br>DeepSeek<br>Grok

What it does

Three ways Theia keeps your AI honest.

Grounded checks against primary sources, plus an on device sycophancy checker for your convenience.

Live sycophancy meter

A gauge sits beside every chat and scores, in real time, how much the model is flattering you versus<br>telling you the truth, powered with a custom trained model.

Fact-checks with sources

Highlight a claim or evaluate a whole reply. Theia returns a verdict and confidence.

Free on-device mode

Run Gemini Nano locally on your own device and verify claims with live web search plus free<br>public sources like Wikipedia, Wikidata, PubMed, OpenAlex, Crossref, SEC EDGAR and more.

Free & unlimited

How it works

A few clicks away from the truth...

01

Install & pin

Add Theia to Chrome and open any AI chat. The meter appears automatically.

02

Chat as usual

Theia reads the assistant's replies and scores them.

03

Verify anything

Highlight text or click "Evaluate LLM Message" for a full, sourced fact-check in seconds.

Free

Fact-check as much as you want.

On-device mode runs a local Gemini Nano model and checks claims against live web search and free<br>public sources, so you can verify without limits or a subscription. Faster cloud models are<br>available too, with a free tier.

Unlimited fact-checks in on-device mode.

No credit card needed to get started.

Stronger cloud models (GPT 5.4 mini, GPT 5.4) available with a free tier and Premium.

Stop taking your AI's word for it.

Add Theia to Chrome and get a second opinion on every answer, always grounded with sources.

Add to Chrome