There have been at least three threads here at THG (although not all that recent) about the threat cocoa-bean-hull mulch presents not only to dogs, but cats as well:
https://www.helpfulgardener.com/forum/viewtopic.php?t=8045
https://www.helpfulgardener.com/forum/viewtopic.php?t=18194
https://www.helpfulgardener.com/forum/viewtopic.php?t=8019
Additional information is available at the ASPCA's Poison Control page: www.aspca.org and follow the links.
The makers of this mulch do NOT label their bags about the toxicity, and many dogs die EACH YEAR because of it.
I know there's a wonderful commercial composting facility up near you (and, of course, can't remember its name ATM). They're bound to have a safe soil amendment/mulch that would do what you need and not poison our four-legged friends.
I'll post here again if I remember the name...
Cynthia H.
Sunset Zone 17, USDA Zone 9