The Code Analysis Repository & Modelling for E-Neuroscience (CARMEN) project aims to enable broad sharing of resources, through the provision of a secure, online environment for storage and curation of data, analysis code and experimental protocols, together with the ability to execute data analysis. While the CARMEN system is initially focused on electrophysiology data, it is equally applicable to many domains outside neuroscience. Metadata are essential for a system such as CARMEN that has the potential to store thousands of data collections and analysis codes; without metadata, resource discovery, interpretation, evaluation and re-use would be severely impeded. Therefore, when any resource (data, service or workflow) is added to the system, users must provide adequate descriptions. These descriptions form a metadata repository that is searchable to allow users to find any kind of resource held in the system, assuming that the user has appropriate access rights. This paper discusses and explores the project's approach to implementing such a metadata repository that meets both system requirements and user expectations. Initial approaches were refined after user evaluations, and a more practical approach was followed that better aligned with the aims of the users and the project as a whole.