- "Toggle CRiSP/Brief emulation minor mode.
-With ARG, turn CRiSP mode on if ARG is positive, off otherwise."
+ "Toggle CRiSP/Brief emulation (CRiSP mode).
+With a prefix argument ARG, enable CRiSP mode if ARG is positive,
+and disable it otherwise. If called from Lisp, enable the mode
+if ARG is omitted or nil."