The cache

Every run keeps an ordinary state file as a cache, and three rules govern it: it is never consulted for ownership; when it and the live system disagree, live wins; losing it costs a slower run and nothing else. Stale is the expected condition. The project is named after fermented tofu.

The file is a stock-format state file on purpose. Copy it into place, remove the live block, and stock OpenTofu plans, converges and destroys with it. A cache you may lose without cost is also a state file you may keep without ceremony.

PlatformWhat the state file is
AWS choudoufu-cache.tfstate under the data dir. Never consulted for ownership; when it and the live system disagree, live wins; losing it costs a read.
Kubernetes The same file and the same three rules.

The two other per-platform answers that follow from the marker, the gate and the inventory command, are on each platform’s own pages; the table below is the same data.

PlatformWhat fences a write
AWS IAM conditions on aws:ResourceTag/tofu-estate and aws:RequestTag/tofu-estate. They fence reads and writes, per resource, and bind the credential rather than the binary.
Kubernetes One ValidatingAdmissionPolicy (live/kubernetes/estate-boundary.yaml) whose CEL reads the label off oldObject and object and asks the authorizer whether the caller holds use on estates.choudoufu.intentius.io/<estate>; the grant is a ClusterRole. It fences create, update and delete only, never list or get, not subresources, and it is a cluster-wide object a cluster admin installs. Until it is installed the label is advisory.
PlatformHow anyone lists an estate without the tool
AWS aws resourcegroupstaggingapi get-resources --tag-filters Key=tofu-estate,Values=<estate>
Kubernetes kubectl get <kind> -A -l tofu-estate=<estate>, one kind at a time; /apis lists every kind the cluster serves, CRDs included.