Abstract. In an open environment populated by heterogeneous information services integration will be a major challenge. Even if the problem is similar to planning in some aspects, the number and the difference in specificity of services makes existing techniques not suitable and requires a different approach. Our solution is to incrementally solve integration problems by using an interplay between service discovery and integration alongside with a technique for composing specific partially matching services into more generic constructs. In this paper we present a directory system and a number of mechanisms designed to support incremental integration algorithms with partial matches for large numbers of service descriptions. We also report experiments on randomly generated composition problems that show that using partial matches can decrease the failure rate of the integration algorithm using only complete matches by up to 7 times with no increase in the number of directory accesses r...