HITL Architecture for Regulated AI: Designing Async Approval Queues & Dual-Custody Triggers

import crypto from "crypto";

export interface AgentActionRequest {
  actionId: string;
  agentId: string;
  riskTier: "LOW" | "MEDIUM" | "CRITICAL";
  payload: Record<string, any>;
  signatures: Array<{ approverRole: string; approverId: string; signature: string }>;
}

export class DualCustodyGatekeeper {
  private requiredRoles = ["COMPLIANCE_OFFICER", "RISK_LEAD"];

  verifyActionEligibility(request: AgentActionRequest): { canExecute: boolean; missingRoles?: string[] } {
    if (request.riskTier === "LOW") {
      return { canExecute: true };
    }

    // High/Critical risk requires dual-custody approval signatures
    const signedRoles = request.signatures.map((s) => s.approverRole);
    const missing = self_required(this.requiredRoles, signedRoles);

    if (missing.length > 0) {
      return { canExecute: false, missingRoles: missing };
    }

    return { canExecute: true };
  }

  generateAuditRecord(request: AgentActionRequest): string {
    const record = {
      actionId: request.actionId,
      timestamp: new Date().toISOString(),
      agentId: request.agentId,
      approvers: request.signatures.map((s) => s.approverId),
      payloadHash: crypto.createHash("sha256").update(JSON.stringify(request.payload)).digest("hex"),
    };
    return JSON.stringify(record);
  }
}

function self_required(required: string[], present: string[]): string[] {
  return required.filter((r) => !present.includes(r));
}