That would be because I made it up on the spot. Good to know it sounded like a WotC item.
Items are priced by their power. It's not an overly strong item. You're the DM, don't worry about it too much. The item primarily serves to reduce bookkeeping and mundane hassles. Okay, it lets you take your animal companion with you anywhere; of course, if someone else knows the command-word, your animal companion isn't in the fight... but it's for a Ranger's companion anyway, so that's not much of an issue. There are a great many spells that can be used to similar effect. Price it like the Efficient Quiver / Quiver of Elhonia (1,800 gp); as it serves essentially the same purpose (just in a different context). Make it require, oh Reduce Animal and Goodberry, and call it good.