# Senior Helm playbook

Compressed reference for the senior-only Helm extension. Pair with [cheat-sheet.md](./cheat-sheet.md), [GLOSSARY.md](./GLOSSARY.md), and [repo-helm-map.md](./repo-helm-map.md).

## The senior shift
Intermediate understanding is: "I know charts, values, templates, helpers, library charts, hooks, releases, and the repo’s Helm basics."

Senior understanding is: "I can explain what Helm truly owns, why this repo chose the copy model, how values behave like a chart API, where rollback confidence ends, and how to review Helm designs honestly."

## Six senior lenses
1. **Truthfulness beats slogans** — explain what Helm renders and tracks, not vague claims about owning the whole deploy.
2. **Copy-model honesty matters** — self-contained copied templates buy clarity and reproducibility, but drift risk remains real.
3. **Values are a contract** — defaults, globals, and override layers are a public configuration interface.
4. **Release safety is layered** — hooks, migrations, revisions, and rollback all have limits.
5. **Quality is more than rendering** — successful template output does not prove a chart is easy to operate or well-governed.
6. **Review is about guarantees and discipline** — ask what is enforced, what is conventional, and what operators must simply remember.

## Senior review checklist
- What exactly does Helm own here, and what belongs to Skaffold, Kubernetes, or runtime code?
- Is the copy model being described honestly, including drift risk and regeneration requirements?
- Do the values behave like a coherent public interface or a pile of exceptions?
- Are hook lifecycle claims honest about gating, side effects, and reversibility?
- Does the release story overstate rollback confidence?
- Are chart quality claims grounded in actual repo enforcement rather than idealized tooling?
- Could a new engineer understand where the source of truth lives and how to operate this chart safely?

## Interview answer shapes
### What does Helm really own?
It owns chart packaging, templating, values application, install/upgrade behavior, and release history — not the entire runtime or orchestration story.

### Why use the copy model?
To keep charts self-contained and generated templates visible in git, while accepting drift risk and the need for regeneration discipline.

### Why are values really a chart API?
Because they are the public configuration surface operators and tooling rely on, so unstable values design becomes operational pain.

### What makes rollback believable?
Honest treatment of hooks, migrations, side effects, compatibility, and what Helm revisions can versus cannot restore.

### What is the real job of a senior Helm reviewer?
To ask what the chart truly guarantees, where it depends on convention instead of enforcement, and how understandable it stays under pressure.