The Forensic
Data Architecture.
Sentinel does not overwrite state. It records an immutable, append-only ledger of physical reality. Every event is cryptographically signed and chained to the previous event, making retroactive falsification mathematically impossible.
{
"event_id": "uuid-v4-7a3f-9c2d-bed04",
"event_type": "ROOM_VACANT",
"physical_timestamp": "2026-08-24T09:12:04+05:30",
"logged_timestamp": "2026-08-24T09:12:05+05:30",
"room_id": "D-A415",
"floor": 4,
"actor_role_id": "Nurse",
"source": "WhatsApp",
"previous_state": "OCCUPIED",
"new_state": "VACANT",
"payload": {},
"cryptographic_signature": "sha256...",
"parent_event_id": null,
"correlation_id": "turnover_D-A415_20260824_0912"
}The Three Laws of Sentinel Data
1. Append-Only
The database explicitly prohibits `UPDATE` and `DELETE` operations on the event store. The ledger is a permanent, WORM (Write Once, Read Many) record.
2. Cryptographically Signed
Every event carries an HMAC-SHA256 signature generated by the device. If an event is tampered with, the signature fails, and the data is quarantined.
3. Hash-Chained
Each event contains the hash of the preceding event. If one event is altered, the hash chain breaks, making the tampering forensically detectable.
See how this data powers the system.
The event schema is the foundation of the 7-Layer Stack. See how it drives real-time constraint resolution and the Live Dashboard.