Hydroxycinnamoyl transferase that catalyzes the transfer of an acyl from p-coumaryol-CoA to tryptamine, to produce coumaroyl tryptamine. Serotonin and tyramine serve as acyl acceptors in vitro. Can use caffeoyl-CoA, and to a lesser extent feruloyl-CoA, as acyl donors. Belongs to the plant acyltransferase family.