Arm Linaro Fraunhofer SIT Fujitsu AMD Alibaba Cloud In the Remote Attestation Procedures (RATS) architecture, Verifiers require Endorsements and Reference Values to assess the trustworthiness of Attesters. This document specifies the Concise Selector for Endorsements and Reference Values (CoSERV), a structured query/result format designed to facilitate the discovery and retrieval of these artifacts from various providers. CoSERV defines a query language and corresponding result structure using CDDL, which can be serialized in CBOR format, enabling efficient interoperability across diverse systems.