Thank you;
I could not get it to work using ${initscript.sourceFile} instead used ${initscript.sourceFile.parentFile} based on the discussion in Best approach to apply custom plugin to root project via init script in a custom distribution
// Make the SINGLE plugin visible to all projects, by including it in the build script classpath. rootProject { buildscript.dependencies { classpath files("${initscript.sourceFile.parentFile}/../lib/plugins/samp1-1.0.0.jar") } }
It was also helpful to include multiple plugins by pointing to the directory instead of specific file.
// Make MULTIPLE plugin visible to all projects, by including it in the build script classpath. include filter is Optional rootProject { buildscript.dependencies { classpath fileTree(dir: "${initscript.sourceFile.parentFile}/../lib") } }