Status: accepted, 2026-10-26. Decided by the author (open decision D1) in session 01.

Context

ADR-0001 left a third execution tier open: a KVM-capable VM, provisioned with Terraform, where local sandboxes could run away from the author’s laptop. It would need a cloud provider and a region, remote Terraform state, and a make destroy next to every make apply.

Options considered

  1. Keep Tier T and pick a provider now.
  2. Drop Tier T. Cloud sandboxes already make the series independent of the author’s laptop.
  3. Defer until the cloud tier has been tried.

Decision

Option 2: drop it.

Consequences

  • No infra/terraform/, no Terraform in the devcontainer, and no provider account to manage or pay for.
  • Every run by the author happens in cloud sandboxes (Tier C). The Codespace can’t run local sandboxes (/dev/kvm isn’t accessible, and the author chose not to change group membership; see ADR-0001).
  • The local tier (Tier L) stays in the scripts for readers with KVM-capable machines. An example’s README says “local tier not tested: no KVM available” unless someone has actually run it locally (CLAUDE.md §11).
  • To revisit only if cloud sandboxes become unavailable or unaffordable for the series.