Preflight runs let platform engineers preview changes before they're applied. Today, Terraform-based Building Blocks support this well, but Building Blocks that trigger pipelines (GitHub Actions, GitLab, Azure DevOps) don't have a reliable, consistent way to distinguish a preflight run from a real apply run inside the pipeline itself. This makes it hard to build a pipeline that safely previews changes without risking an unintended apply.

Give pipeline-based Building Blocks (GitHub Actions, GitLab, Azure DevOps) first-class, consistent support for preflight runs, so pipeline authors can reliably detect and handle a preflight the same way across all three integrations.