The Internet is not only providing data for users to browse, but also databases to query, and software agents to run. Due to the exponential increase of deployed agents on the Internet, automating the search and selection of relevant agents is essential for both users and collaboration among di#erent software agents. This paper first describes the agent capability description language Larks. Then we will discuss the matchmaking process using Larks and give a complete working scenario. The paper concludes with comparing our language and the matchmaking process with related works. Wehave implemented Larks and the associated powerful matchmaking process, and are currently incorporating it within our RETSINA multi-agent infrastructure framework