Methods, systems, and apparatus, including computer programs encoded on computer storage media, for automatically identifying and installing missing packages during an instrumented build. One of the methods includes intercepting, by a source code analysis system, a call from a build system that references a file system path. If the file system path does not exist on the build system, a search is performed to identify a source code package having a filename in the file system path, and the source code package is installed on the build system. After installing the source code package on the build system, the intercepted call is executed.