ThumbGate is the safety net for AI coding agents. Give a thumbs-down to a bad action once, and your agent will never ship that mistake again. Every downvote becomes a concrete prevention rule and a pre-action gate that blocks known-bad actions before they execute across 36 tools (git, shells, files, HTTP, clouds). v0.8.4 ships improved rule validation, faster gate checks, and a live dashboard. Unlike Mem0 (memory) or SpecLock (specs), ThumbGate enforces lessons at the moment of action.