ISO 8601 creation timestamp.
Optionalinstructions_blake3 of the full prompt/task text that produced the layer.
Human-readable why. Mandatory: the ifc layer log line.
Filled on merge layers only.
Parent layer ids in the change DAG.
Capability-grammar scope claims (07-security.md §7.1).
ed25519 signatures over the layer id; excluded from the id itself.
Base the layer was authored against (null for base/import layers).