ATLAS Metadata Interface (AMI), a generic metadata framework

The ATLAS Metadata Interface (AMI) is a mature application of more than 15 years of existence. Mainly used by the ATLAS experiment at CERN, it consists of a very generic tool ecosystem for metadata aggregation and cataloguing. We briefly describe the architecture, the main services and the benefits of using AMI in big collaborations, especially for high energy physics. We focus on the recent improvements, for instance: the lightweight clients (Python, Javascript, C++), the new smart task server system and the Web 2.0 AMI framework for simplifying the development of metadata-oriented web interfaces.