Policy Engine

The ABS Policy Engine is the core decision-making component of the ABS Kernel. It evaluates every agent action against a set of active policies to determine whether to ALLOW, DENY, or ESCALATE the operation.

Architecture

The engine operates on a Fail-Close principle: if a policy cannot be evaluated or an error occurs, the default action is to block.

Decision Flow

1. Event Ingestion: The engine receives an EventEnvelope containing the agent's intent, payload, and metadata (see Decision Envelope).
2. Sanitization: Input safeguards remove PII and check for prompt injection.
3. Policy Evaluation: The active policy for the event type is executed.
4. Risk Scoring: A risk score (0-100) is calculated based on:
   • Static Rules: Regex matches, keyword blocks.
   • Contextual Analysis: Velocity checks, anomaly detection.
   • Sequence Analysis: Recognition of dangerous workflows.
   • Trust Score: Historical reputation of the agent.
5. Verdict:
   • ALLOW: Risk score < 30.
   • ESCALATE: Risk score 30-79 (requires human approval).
   • DENY: Risk score >= 80 or explicit block.
6. Immutable Log: The decision is signed and recorded in the Write-Ahead Log (WAL).

1. Policy Structure

All policies are defined in YAML and follow the ABS Schema 2.1.

apiVersion: abs/v2
kind: Policy
metadata:
  name: financial-safeguards
  version: 1.0.0
spec:
  target:
    agents: ["*"]
    tools: ["stripe_api", "bank_transfer"]
  
  rules:
    - id: "limit-high-value"
      description: "Block transfers over $10k without approval"
      condition:
        type: "json_path"
        path: "$.arguments.amount"
        operator: "gt"
        value: 10000
      action: "ESCALATE"
      
    - id: "block-offshore"
      description: "Prevent transfers to non-approved jurisdictions"
      condition:
        type: "regex"
        path: "$.arguments.destination_country"
        pattern: "^(KY|VG|PA)$" # Cayman, BVI, Panama
      action: "DENY"

2. Policy Actions

3. Dynamic Context (Redis)

Policies can reference dynamic state using the ${ctx.*} syntax:

- id: "velocity-check"
  condition:
    type: "rate_limit"
    key: "${ctx.agent_id}"
    limit: 10
    window: "1m"
  action: "DENY"