This review article in Drug Metabolism Reviews discusses all major and minor psychoactive metabolites of psilocybin. Specifically, psilocybin is dephosphorylated by alkaline phosphatase to psilocin which is then further metabolized, resulting in psilocin-O-glucuronide which is the main metabolite found in the urine.
Article Reviews Metabolism of Psilocybin and Psilocin
Researchers discuss how the body metabolizes psilocybin and review all the major and minor metabolites.