Policies

A policy is a named collection of rules that define what discounts are allowed in B2B pricing.

Policy Structure

interface Policy {
  id: string;
  name: string;
  rules: PolicyRule[];
}

Required Fields

id: Unique identifier for the policy
name: Human-readable name
rules: Array of rules to enforce

Policy Rules

Each rule uses the json-rules-engine format with conditions and events:

interface PolicyRule {
  name: string;
  conditions: {
    all?: RuleCondition[];
    any?: RuleCondition[];
  };
  event: {
    type: string;
    params?: Record<string, unknown>;
  };
  priority?: number;
}

Example Rule

const marginFloorRule: PolicyRule = {
  name: 'margin_floor',
  conditions: {
    all: [
      {
        fact: 'calculated_margin',
        operator: 'lessThan',
        value: 0.15
      }
    ]
  },
  event: {
    type: 'violation',
    params: {
      message: 'Calculated margin falls below 15% floor'
    }
  },
  priority: 1
};

Default Policy

The default policy includes three rules:

import { defaultPolicy } from '@guardrail-sim/policy-engine';
 
// Includes:
// - margin_floor: 15% minimum margin
// - max_discount: 25% maximum discount
// - volume_tier: 10% base, 15% for qty >= 100

Custom Policies

Create custom policies with your own rules:

import { PolicyEngine } from '@guardrail-sim/policy-engine';
import type { Policy } from '@guardrail-sim/policy-engine';
 
const holidayPolicy: Policy = {
  id: 'holiday-2026',
  name: 'Holiday Sale Policy',
  rules: [
    {
      name: 'holiday_max',
      conditions: {
        all: [
          { fact: 'proposed_discount', operator: 'greaterThan', value: 0.30 }
        ]
      },
      event: {
        type: 'violation',
        params: { message: 'Holiday discount cannot exceed 30%' }
      }
    }
  ]
};
 
const engine = new PolicyEngine(holidayPolicy);

Rule Conditions

Conditions use facts, operators, and values:

Operator	Description
`equal`	Exact match
`notEqual`	Not equal
`lessThan`	Less than value
`lessThanInclusive`	Less than or equal
`greaterThan`	Greater than value
`greaterThanInclusive`	Greater than or equal
`in`	Value in array
`notIn`	Value not in array
`contains`	Array contains value

Available Facts

The policy engine provides these facts for conditions:

Fact	Description
`order_value`	Total order value in dollars
`quantity`	Total units in order
`product_margin`	Base margin (0.40 = 40%)
`proposed_discount`	Requested discount (0.15 = 15%)
`calculated_margin`	Margin after discount
`customer_segment`	Customer tier (gold, silver, etc.)

Best Practices

Name rules clearly: Use descriptive names like margin_floor not rule1
Set priorities: Higher priority rules run first
Provide messages: Include helpful violation messages
Test thoroughly: Use multiple test scenarios

Policies

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