KARANI
Not "does it choose not to." Grades live in a separate database that every part of Karani is locked out of — by Google Cloud's permission system, not by good intentions. This page lets you watch it try.
Press the button and this very service — the one rendering the page you are reading — will attempt to create a grade record, live, using its own identity. If the boundary holds, Google Cloud refuses it before Karani's own code gets a say.
Why this matters: a tool that promises not to grade can break its promise in an update. A tool with no field for a grade, writing to a database it cannot reach, needs a redesign to break it — and a redesign is visible in a way a prompt change never is.