Designing a Community Skill for AWS Transform Custom: AWS Glue 5.0 Upgrade Readiness

TL;DR

I designed a proposed AWS Transform Custom community skill that prepares Glue 2.0, 3.0, and 4.0 repositories for Glue 5.0. It separates safe mechanical transformations from changes that require human evidence, generates a migration report, and preserves already-compatible files unchanged. Because I didn't have live atx access, the benchmarks in this post are explicitly labeled manually simulated, not agent-executed. The proposal is open as issue #75 — not yet merged, not yet a pull request.

The missing data-engineering transformation

AWS Transform Custom can apply agent-driven code transformations across a single repository — or thousands of them at once, via AWS Batch and Fargate. As of July 30, 2026, its public sample repository, aws-samples/aws-transform-custom-samples, contained three community-contributed transformations: an EKS version-upgrade-readiness skill, a JBoss-to-Spring-Boot migration, and a Kubernetes readiness migration. None of them touched data engineering.