Linaro Fraunhofer SIT Transmute COSE (STD96) is not an end-to-end system with guaranteed interoperability. It is designed to serve a range of use cases and therefore it has a lot of options. In general, two COSE implementations that want to interoperate require an agreement on which subset of COSE features they will use. This document provides a set of rules for specifying such agreements as "COSE profiles" and registers a new COSE header parameter for in-band signalling of profile information.