Thank the stars that they have every reason not to linger on any of that. It's such a uniquely useless line of inquiry, so fundamentally exasperating that they're better off ignoring it and the twinge of resentment or despondency entirely in favor of--

"I've written it down for you. You can read, can't you?" Bounding to the cloak, Bartimaeus retrieves a scrap of paper from some inside pocket. He thrusts it into Kitty's hands, then takes her by the shoulders and steers her into the smaller of the two pentacles. "Just say the words exactly as they are there."

He scampers into the larger pentacle, dusts his hands, and smooths back his hair. Stands with his feet shoulder width apart and-- "Oh. Feel free to have the cloak when I'm gone by the way." And-- "And don't forget to erase these pentacles before you go."