Goodheart Labs is working on Common Notes, described as Twitter Community Notes but for everything.

Judged as of 2026-10-19. True: on that date, Goodheart Labs was building a project called Common Notes, described as a general-purpose Community Notes-style system, that is, community notes for content beyond Twitter/X. Mostly true: Goodheart Labs was working on such a project, but its name or description differs slightly. Mixed: the project existed but was not run by Goodheart Labs (for example, a collaborator led it), or it had been stopped. Mostly false: Goodheart Labs had a related project, but it does not match the description. False: Goodheart Labs had no such project.

Set before the research began.

1. E1 Goodheart Labs · 27 November 2023

   “Community Notes for everything: a browser extension. Our claim-checking pipeline produces notes on Substack articles and YouTubers that are regularly visited by our users and displays notes directly on the page.”

2. E2 Goodheart Labs · 27 November 2023

   “Common Notes, our browser extension, brings the same technology to Substack and YouTube.”

Goodheart Labs' own homepage names Common Notes as its browser extension, which brings its Community Notes technology to Substack and YouTube (E2). It describes the project as "Community Notes for everything", with notes shown on Substack articles and YouTube pages (E1). That matches the claim's name and its description as general-purpose Community Notes beyond Twitter/X. The page is independent of the subject, Scott Alexander. Its listed date (2023-11-27) does not pin down timing exactly, but it presents the project as ongoing and gives no sign it had stopped.