The tools (TOOLS) software development kit (SDK), or TOOLS SDK, is an integration effort for a collection of software packages used to monitor, analyze, and diagnose the performance and behavior of computational science applications and systems software developed under the Department of Energy (DOE) Advanced Scientific Computing Research (ASCR). The software products target using Spack, an HPC-targeted source-based package manager, for deployment on HPC platforms and beyond. The primary product of this project is the toolssdk Spack meta-package which builds a set of TOOLS SDK member packages together in a way that enables optimal features for target environments as well as interoperable features provided by other packages within the TOOLS SDK. The TOOLS SDK is an outcome of the work within the DOE STEP project and is sustained and advanced by the DOE PESO project.