Preheat oven to 350F. Line a cookie sheet with parchment paper and set aside. Get 2 sheets of parchment for rolling and a rolling pin ready, as well as your stamp and a knife (if using; otherwise whatever cookie cutters you like).
Whip coconut oil in a mixing bowl with a hand mixer to fluff it up a little. Add everything except rice flour and arrowroot, and mix once more into a uniform mixture. Add in the flour and arrowroot and use your hands to start mixing the mixture until you can lump it into a ball. If after kneading it a little it's too crumbly, add another ½ tbsp agave and knead into a ball then flatten into a disk.
Roll out the dough into somewhere between ⅛" and ¼" thickness in between the two sheets of parchment (thinner -- crunchier, thicker -- softer cookies). Imprint the dough with the stamp (leave room between each imprint so they don't affect one another when you press into the dough to make more -- I can usually get about 4 prints in at this stage). Use a sharp knife to cut out the edges of the imprint into a square cookie shape. Use a wide spatula to carefully transfer the cookie onto your cookie sheet. Collect all dough scraps, roll out again, and repeat to create 2 more cookies.
Bake in a pre-heated oven for 15 - 19 minutes (15 -- crunchy around the edges, but very soft in center, 19 -- very crunchy. You can also pick something in between :) ). Remove from oven and cool on a rack for at least 10-20 minutes (note: they will be soft when you pull them out, but will harden once they cool. Enjoy!