Seeing files after downloading? That’s the installation package.
Chrome loads the whole folder. You don’t need to open or run the individual code files.
Follow these four steps to add it to your toolbar.
1. Extract the ZIP
On Windows, right-click the download → Extract All → Extract. On Mac, double-click the ZIP. Keep the extracted folder.
2. Open Chrome’s extensions page
Paste this address into a new Chrome tab. Turn on Developer mode at the top right.
chrome://extensions
3. Click “Load unpacked”
Select the extracted folder containing manifest.json, then choose Select Folder. Don’t select the ZIP or a single file.
4. Pin it and check your first claim
Click Chrome’s puzzle icon → pin Second Opinion. On a webpage, select a claim and click our icon. Review it, then choose Find evidence.
Already installed, or stuck on a step?
Updating: extract the new ZIP into the same installation folder, replace its old files, then click the reload icon on Second Opinion’s card at chrome://extensions. Check that it shows v1.1.0.
“Manifest missing”: choose the inner folder that has manifest.json directly inside it.
No selected text: paste your claim into the extension. Chrome settings pages and some PDF viewers don’t allow capture.
Managed school or work browser: if Developer mode is disabled by your administrator, use the website claim checker.
Choose Add custom connector and paste the server URL.
Enable the connector in your conversation, then request evidence for a public claim.
Official setup guide Workspace administrators may restrict connectors. Installation happens in your Claude account.
TRY THIS WITH YOUR CONNECTOR
“Use Second Opinion to find evidence for the claim ‘Regular physical activity improves sleep quality in adults.’ I consent to searching public sources. Show the actual excerpts, gaps, and provider status. Don’t claim the browser models have run.”
Where the two models run
The extension and connectors retrieve evidence through our API. DeBERTa and RoBERTa run in your browser when you explicitly start them in the claim checker. They are not secretly running inside ChatGPT or Claude.
Source links, pinned model versions, exact input excerpts, disagreement, and your review stay visible. Signed research receipts detect altered records while the signing key remains private.
This is not copyproof software. The value comes from reliable evaluation, useful review workflows, and evidence people can inspect. No signature or model agreement certifies truth.
Public research search sends the selected claim to Second Opinion and the relevant research indexes. Optional published fact-check lookup needs an operator-configured key. Local passage text stays in your browser; model downloads contact Hugging Face. Don’t send confidential claims to public search.