Claim Check by Signal & Shadow

Right-click selected text to search fact-check databases in parallel. Every check logged for chain of custody.

Claim Check is a browser extension for investigative journalists, fact-checkers, OSINT practitioners, and researchers. Highlight any claim on any web page and right-click to run two well-targeted fact-check searches in parallel. Every action is logged locally for reproducibility. The extension itself makes no network requests. No telemetry, no analytics, no remote code. Source code is available for review and a static privacy audit script ships with the extension. WHAT IT DOES Highlight any claim on a web page. Right-click. The browser's context menu now includes a Claim Check submenu. Choose Search both fact-check sources to open both searches in parallel. Choose one source to open just that. Choose Log without searching to record the observation without contacting any third-party service. The two searches are: A claim-aware meta-search that indexes IFCN-certified fact-checkers worldwide, designed specifically for the claim-text-as-input case rather than keyword search. A site-restricted Google search across the major fact-check publications, which uses Google's full-text indexing and ranking instead of each publication's brittle internal search engine. The full list of fact-check publications covered is in the extension source where it can be reviewed. Click the toolbar icon to see the activity log. Every action records timestamp, source page URL, the claim text, a short hash of the claim for stable identity, and the search performed. Export the log as a SHA-256 signed zip bundle compatible with the standard sha256sum -c verifier. WHY TWO SEARCHES, NOT TEN An earlier design opened ten tabs, one per fact-check database. In practice each database's internal search engine is keyword-based and rarely returns useful hits for long-form claim text. The two searches in the current design are substantially more useful: a claim-aware meta-search built for this specific use case, plus a Google site-restricted search that uses Google's full-text index of the major fact-check publications. READ THIS BEFORE INSTALLING Fact-check searches are disclosures to third parties. Each search opens a new browser tab to a Google URL containing the claim text you searched for. Google sees the claim text, your IP address, your user agent, and the Referer header from the page you were on. Google's privacy policy applies to those queries. The extension itself does nothing with this data. Every search opens a normal browser tab to a URL the user explicitly chose. The tool is built for practitioners who understand this and want reproducibility and logging of their checks, not anonymity. For sensitive investigations, use the extension in conjunction with a VPN, Tor, or a dedicated browser profile, and use the Log without searching action when an outbound search would compromise the investigation. ARCHITECTURE Claim Check uses Chrome's contextMenus API with the selection context, which provides the highlighted text whenever the user right-clicks a selection. No content script. No host permissions. No <all_urls> matchers. No continuous DOM monitoring. The extension's manifest declares only four permissions: contextMenus, activeTab, storage, downloads. FORENSIC PROVENANCE Every action is captured in a local activity log: timestamp, session ID, claim text, claim hash, source URL, search performed, target URL. The log holds 5,000 entries; the popup warns at 4,500 so you can export before any entries are evicted. Export bundles carry the SHA-256 of every file alongside a capture manifest documenting the export. Anyone receiving a bundle can verify integrity offline. Aligned with the Berkeley Protocol on Digital Open Source Investigations. Built and maintained by Signal & Shadow, an independent investigative-journalism and OSINT publication. More at signalandshadow.io.