Keep build actions focused on their core responsibility and move complex logic to appropriate abstraction layers like builders or configuration components. Build actions should contain minimal action-specific branching and avoid tight coupling to implementation details. This principle improves build system maintainability and reliability in CI/CD pipelines by: - Making actions easier to debug when builds fail - Reducing complexity that can lead to unpredictable behavior - Enabling better separation of concerns for different build phases - Avoiding architectural decisions that make the system harder to extend For example, instead of adding conditional logic directly in a compile action: ```java // Avoid: Complex branching in action if (featureConfiguration.isEnabled(CppRuleClasses.CPP_MODULES)) { if (dotdFile != null) { outputs.add(dotdFile); } } ``` Move the logic to the builder where it belongs: ```java // Prefer: Logic in builder, clean action // Builder handles the conditional logic // Action just processes what builder provides ``` Similarly, avoid introducing special artifacts or complex coupling that makes the build system "un-Starlarkifiable" or harder to maintain. When build actions stay focused and delegate complex decisions to appropriate layers, the entire CI/CD pipeline becomes more reliable and easier to troubleshoot.