Not Brother — X Relationship Observer

Annotate relationship evidence visible on X and keep a private observation history in this Chrome profile.

Not Brother is a local-first relationship observer for X. While you browse x.com normally, it annotates relationship evidence already visible on the page and keeps a private observation history in this Chrome profile. The extension can identify mutual follows, accounts you follow that do not follow you back, accounts that follow you, opportunistic evidence that an account has blocked you, and changes between previously observed states. Attributable changes are labeled as followed you back, unfollowed you, or blocked you; the compact X-page panel keeps one aggregate change count. Insufficient evidence produces no label and no saved record. Use the Chrome side panel for a compact overview or open the Relationship Fieldbook to search, filter, sort, review changes, export JSON or CSV, merge a JSON backup, and delete local records. The observer panel on X can minimize to an NB floating button and retains its state locally. Not Brother only processes account identity and relationship hints rendered on the x.com page you are viewing. It does not auto-scroll, crawl profiles, read direct messages or cookies, call X APIs, click follow, unfollow, block, or mute controls, or send observation data to the developer. X interface changes can affect detection until the extension is updated. Not Brother is an independent extension and is not affiliated with, endorsed by, or sponsored by X Corp. Source code is available at https://github.com/interjc/chrome-x-not-brother. Report problems and ask for support on the repository Issues page.