Angle Tool is a modeling add-on for Blender that works in Edit Mode to build corner geometry quickly. After selecting part of your mesh and specifying an Active Edge, the Angle Tool command turns your geometry around that edge and extends it to form a geometric corner. It lets you create this kind of geometry on the fly, avoiding the extra steps that would otherwise be needed to reach similar results.
Beyond the core command, the add-on includes a Curve Mode and an Extend Mode alongside its default Angle Mode. Numeric Input lets you type specific values on the keyboard while the tool is running, and a heads-up display in the 3D viewport shows information and instructions as you work. Clicking the Toolbar icon brings up a gizmo with a Curve Mode toggle and a Segments adjustment slider. The tool can also be called from a hotkey.
Version 1.35 was released on November 26th, 2023, with a quick fix for newer Blender versions where the deprecated bgl module had stopped the add-on's UI elements from working. A demo video is available.