Safety by Design
The same question every industrial buyer asks. Here's how we answer it.
5-Tier Authorization
Brain's AI agent operates under a strict 5-tier model. Read operations are always allowed. Safety-critical actions require admin approval AND explicit confirmation. No exceptions, no shortcuts, no black boxes.
Category
Read
Authorization
Always allowed
Example
“What's the current temperature?”
Category
Inform
Authorization
Always allowed
Example
“Show me the alarm log”
Category
Configure
Authorization
Agent enabled (default)
Example
“Create a new tag for tank 3”
Category
Control
Authorization
Operator approval or pre-approved rule
Example
“Start the heater at 60°C”
Category
Safety-Critical
Authorization
Admin approval + confirmation
Example
“Disable the overpressure alarm”
Auto-Lock
If Brain's AI agent executes 3 or more Tier-3 actions in 60 seconds, all autonomous modes are disabled automatically. Requires manual re-enable by an admin. This prevents runaway loops and accidental cascading changes.
T+0s
Tier-3 action #1
Within 60s window
T+18s
Tier-3 action #2
Within 60s window
T+47s
Tier-3 action #3
Within 60s window
Result
All autonomous modes disabled
Requires manual admin re-enable.
Emergency Stop
POST /ai/emergency-stop. Kills all agent activity instantly. Cancels pending actions. Disables all autonomous modes. Notifies all operators. One call, full shutdown.
curl · emergency-stop.sh
POST https://brain.local/ai/emergency-stop
Authorization: Bearer YOUR_ADMIN_TOKEN
Content-Type: application/json
{
"reason": "Unusual behavior detected",
"disable_until": "manual"
}
// Response
HTTP 200 OK
{
"status": "all_autonomous_disabled",
"actions_cancelled": 7,
"operators_notified": 12,
"timestamp": "2026-04-20T14:32:08Z"
}Audit Trail
Every AI action is logged to SQLite with: the tool used, the arguments, the tier, who approved it, when, and what the result was. Queryable via admin dashboard. Exportable for compliance audits. Immutable.
audit_log.sqlite · event #4f82a1c9e
IMMUTABLE{
"id": "evt_4f82a1c9e",
"timestamp": "2026-04-20T14:18:42.193Z",
"tool": "plc.set_setpoint",
"tier": 3,
"args": {
"tag": "HEATER_01.setpoint",
"value": 60.0,
"unit": "celsius"
},
"approved_by": "operator:mkowalski",
"approval_method": "pre_approved_rule:rule_88c",
"result": "success",
"duration_ms": 142,
"previous_value": 55.0,
"session_id": "sess_9a3b7e2"
}Approve & Remember
When an operator approves a Tier-3 action, they can select “Approve & Remember” to create a pre-approved rule. Future identical situations are handled without re-prompting. The agent learns YOUR safety boundaries.
Day 1
Pending approval · Tier 3
Start heater HTR_01 at 60°C?
Tank TK_03 temperature low · warmup sequence required
Operator clicks Approve & Remember. A pre-approved rule is created.
Day 30
✓ HTR_01 → 60°C (auto, rule:88c)
✓ HTR_02 → 45°C (auto, rule:88c)
✓ PUMP_03 ON (auto, rule:91a)
✓ VALVE_V7 → 45% (auto, rule:91a)
✓ HTR_01 → 62°C (auto, rule:88c)
✓ MIXER_M2 → 180rpm (auto, rule:94e)
✓ + 14 more approved operations...
20+ operations executed autonomously. Every one logged, auditable, and revocable.
Change Management
PLC changes go through a Git-native workflow. Every change is proposed as a diff, reviewed by authorized engineers, approved with signature, and deployed with one-click rollback. Zero unreviewed PLC changes. Ever.
01
AI or engineer proposes a PLC change as a Git diff.
02
Authorized engineers inspect the diff, run simulations.
03
Signed approval required before deploy. All signatures logged.
04
One-click deploy with instant rollback. Zero unreviewed changes.