The Scalable Tools Communication Infrastructure (STCI) is an open??source collaborative effort intended to provide high-performance,??scalable, resilient, and portable communications and process control??services for a wide variety of user and system tools.??STCI is aimed???specifically at tools for??ultrascale computing??and uses a component architecture to simplify tailoring the??infrastructure to a wide range of scenarios.??This paper??describes STCI's design philosophy, the various??components that will be used to provide an STCI implementation for a??range of ultrascale platforms, and a range of tool types.??These??include tools supporting parallel run-time??environments, such as MPI, parallel application correctness tools and??performance analysis tools, as well as system monitoring and??management tools.