First Policy

policy:
  id: unique-policy-id
  version: "1.0"
  description: Human-readable description

rules:
  - id: rule-001
    name: descriptive-name
    match: { }      # When does this rule apply?
    action: DENY    # What happens?
    reason: "Why"   # Human-readable explanation

match:
  tool: database
  operation: delete

match:
  tool: email
  operation: send
  parameters:
    to: { external: true }           # Custom predicate
    subject: { contains: "URGENT" }  # String matching

match:
  tool: http
  operation: post
  context:
    data_classification: [PII, PHI]  # Data accessed this session
    prior_actions: { contains: "db.query" }

match:
  risk_signals:
    injection_score: { gt: 0.8 }
    anomaly_score: { gt: 0.7 }

rules:
  - id: limit-bulk-queries
    match:
      tool: database
      operation: query
      parameters:
        limit: { gt: 100 }
    action: MODIFY
    modifications:
      parameters:
        limit: 100
    reason: "Query results capped at 100 rows"

rules:
  - id: approve-destructive-db
    match:
      tool: database
      operation: [delete, drop, truncate]
    action: STEP_UP
    approvers: [database-owner, security-team]
    timeout: 3600
    timeout_action: DENY

rules:
  - id: block-pii-external
    match:
      tool: [email, http, slack]
      parameters:
        destination: { external: true }
      context:
        data_classification: PII
    action: DENY
    reason: "Cannot send PII externally"

rules:
  - id: email-allowlist
    match:
      tool: email
      operation: send
    constraints:
      parameters.to:
        domain_allowlist:
          - "company.com"
          - "trusted-partner.org"
    action: DENY
    reason: "Recipient domain not in allowlist"

rules:
  - id: rate-limit-api-calls
    match:
      tool: external_api
    constraints:
      rate:
        max: 100
        window: 3600  # per hour
    action: DENY
    reason: "Rate limit exceeded"

rules:
  - id: approve-large-transactions
    match:
      tool: payment
      operation: transfer
      parameters:
        amount: { gt: 10000 }
    action: STEP_UP
    approvers: [finance-manager]

from aarm.policy_engine import PolicyEngine

engine = PolicyEngine("policies/my-policy.yaml")

# Test action that should be denied
action = {
    "tool": "email",
    "operation": "send",
    "parameters": {"to": "external@gmail.com"},
    "context": {"data_classification": ["PII"]}
}

decision = engine.evaluate(action)
assert decision.result == "DENY"
assert "PII" in decision.reason