Policy Rules

What is a Policy Rule?

A Policy Rule is a condition → actions pair. When the input facts satisfy the condition, the rule’s actions fire. Rules are evaluated in priority order (0 = highest priority).

IF condition matches → THEN execute actions

Each rule belongs to a specific policy version and has a name, a priority, a condition (tree-structured logic), and one or more actions.

Condition Syntax

Conditions use a tree structure with two node types: SINGLE and GROUP.

LexQ uses its own condition DTO format with type: "SINGLE" / type: "GROUP", field, operator, value, and valueType fields. Do not confuse this with the Console’s internal form representation which may use different field names. Always use the engine format when calling the API or CLI.

SINGLE Condition

A leaf node that compares a single fact against a value:

{
  "type": "SINGLE",
  "field": "payment_amount",
  "operator": "GREATER_THAN_OR_EQUAL",
  "value": 100000,
  "valueType": "NUMBER"
}

GROUP Condition

A branch node that combines child conditions with AND or OR:

{
  "type": "GROUP",
  "operator": "AND",
  "children": [
    { "type": "SINGLE", "field": "customer_tier", "operator": "EQUALS", "value": "VIP", "valueType": "STRING" },
    { "type": "SINGLE", "field": "payment_amount", "operator": "GREATER_THAN", "value": 50000, "valueType": "NUMBER" }
  ]
}

Operators

Operator	Compatible Types	Description
`EQUALS`	All	Exact match
`NOT_EQUALS`	All	Negation
`GREATER_THAN`	NUMBER	`>`
`GREATER_THAN_OR_EQUAL`	NUMBER	`>=`
`LESS_THAN`	NUMBER	`<`
`LESS_THAN_OR_EQUAL`	NUMBER	`<=`
`CONTAINS`	STRING	Substring match
`IN`	STRING, NUMBER	Value is in the provided list
`NOT_IN`	STRING, NUMBER	Value is not in the provided list

Value Types

Type	JSON Value	Example
`STRING`	`"string"`	`"VIP"`
`NUMBER`	`number`	`100000`
`BOOLEAN`	`true / false`	`true`
`LIST_STRING`	`["a", "b"]`	`["KR", "US"]`
`LIST_NUMBER`	`[1, 2]`	`[10000, 20000]`

Nested Conditions Example

(customer_tier = "VIP" AND payment_amount >= 100000) OR region IN ["KR", "JP"]

{
  "type": "GROUP",
  "operator": "OR",
  "children": [
    {
      "type": "GROUP",
      "operator": "AND",
      "children": [
        { "type": "SINGLE", "field": "customer_tier", "operator": "EQUALS", "value": "VIP", "valueType": "STRING" },
        { "type": "SINGLE", "field": "payment_amount", "operator": "GREATER_THAN_OR_EQUAL", "value": 100000, "valueType": "NUMBER" }
      ]
    },
    { "type": "SINGLE", "field": "region", "operator": "IN", "value": ["KR", "JP"], "valueType": "LIST_STRING" }
  ]
}

In the example above, customer_tier and region are custom facts that must be registered in Fact Definitions before use. payment_amount is a system fact available by default.

Action Types

Each rule can have multiple actions. Actions fire sequentially when the condition matches.

Type	Description	Key Parameters
`DISCOUNT`	Apply a discount to a reference amount	`refVar`, `method`, `rate` or `value`
`POINT`	Award points based on a reference amount	`refVar`, `method`, `rate` or `value`, `integrationId`
`COUPON_ISSUE`	Issue a coupon	`couponId`, `integrationId`
`BLOCK`	Block the transaction	`reason`
`NOTIFICATION`	Send notification (SMS, EMAIL, PUSH)	`channel`, `templateId`, `integrationId`
`WEBHOOK`	Call an external URL	`url`, `method`, `payloadTemplate` (optional)
`SET_FACT`	Set an output variable to a fixed value	`key`, `value`
`ADD_TAG`	Add a tag to the execution result	`tag`

DISCOUNT — Percentage

Apply a 10% discount based on payment_amount:

{
  "type": "DISCOUNT",
  "parameters": {
    "method": "PERCENTAGE",
    "rate": 10,
    "refVar": "payment_amount"
  }
}

If payment_amount is 200,000 → discount is 20,000.

DISCOUNT — Fixed Amount

{
  "type": "DISCOUNT",
  "parameters": {
    "method": "AMOUNT",
    "value": 5000,
    "refVar": "payment_amount"
  }
}

SET_FACT — Output Variable

SET_FACT is a literal value setter, not an expression evaluator. It assigns a fixed value to a key in the output variables. It does not support arithmetic expressions or references to other facts.

{
  "type": "SET_FACT",
  "parameters": { "key": "risk_level", "value": "HIGH" }
}

BLOCK — Transaction Block

{
  "type": "BLOCK",
  "parameters": { "reason": "Suspected fraud" }
}

POINT — Percentage

Earn 1% of payment_amount as points:

{
  "type": "POINT",
  "parameters": {
    "method": "PERCENTAGE",
    "rate": 1,
    "refVar": "payment_amount",
    "targetVar": "total_point",
    "integrationId": "<your-point-integration-id>"
  }
}

If payment_amount is 100,000 → earns 1,000 points. total_point is incremented and last_earned_point is set in the output.

POINT — Fixed Amount

{
  "type": "POINT",
  "parameters": {
    "method": "AMOUNT",
    "value": 500,
    "refVar": "payment_amount",
    "integrationId": "<your-point-integration-id>"
  }
}

COUPON_ISSUE

{
  "type": "COUPON_ISSUE",
  "parameters": {
    "couponId": "WELCOME_VIP_2026",
    "integrationId": "<your-coupon-integration-id>"
  }
}

Requires user_id in input facts to identify the recipient. No output variables are modified.

NOTIFICATION

{
  "type": "NOTIFICATION",
  "parameters": {
    "channel": "SMS",
    "templateId": "ORDER_CONFIRM_001",
    "targetVar": "phone_number",
    "integrationId": "<your-notification-integration-id>"
  }
}

Channels: SMS, EMAIL, PUSH. The targetVar specifies which fact contains the recipient address (defaults to phone_number).

ADD_TAG

{
  "type": "ADD_TAG",
  "parameters": {
    "tag": "VIP_VERIFIED",
    "targetVar": "user_tags"
  }
}

Appends the tag to the list fact. Duplicates are automatically prevented. If targetVar is omitted, defaults to user_tags.

WEBHOOK — Basic

{
  "type": "WEBHOOK",
  "parameters": {
    "url": "https://api.example.com/webhooks/orders",
    "method": "POST"
  }
}

Without payloadTemplate, the engine sends all input/output facts as the request body (system variables excluded).

WEBHOOK — With Payload Template

Use payloadTemplate to customize the request body. Template variables are resolved at execution time.

{
  "type": "WEBHOOK",
  "parameters": {
    "url": "<integration-id-or-direct-url>",
    "method": "POST",
    "payloadTemplate": {
      "text": "🔔 Rule {{ruleName}} fired\nCustomer: {{fact.customer_tier}}\nAmount: {{output.payment_amount}}"
    }
  }
}

Available Template Variables

Variable	Description	Example Value
`{{fact.xxx}}`	Input fact value	`{{fact.payment_amount}}` → `150000`
`{{output.xxx}}`	Output variable (after actions)	`{{output.last_discount_amount}}` → `15000`
`{{timestamp}}`	Execution time (ISO-8601)	`2026-04-14T05:30:00Z`
`{{ruleName}}`	Matched rule name	`VIP 20% Discount`
`{{groupName}}`	Policy group name	`Payment Policy`
`{{versionNo}}`	Executed version number	`5`
`{{xxx}}`	Direct fact lookup (shorthand)	`{{customer_tier}}` → `VIP`

Slack requires {"text": "..."}, Discord requires {"content": "..."}. Use payloadTemplate to match each platform’s expected format.

{{fact.xxx}} and {{output.xxx}} reference the same data map. If an earlier action (e.g., DISCOUNT) modifies payment_amount, both {{fact.payment_amount}} and {{output.payment_amount}} reflect the modified value.

Mutex — Rule-Level Conflict Resolution

Within a single version, rules can belong to a mutex group to control how many matching rules fire.

Field	Description
`mutexGroup`	A string key grouping related rules (e.g., `"best-discount"`)
`mutexMode`	`NONE` (default) or `EXCLUSIVE`
`mutexStrategy`	`FIRST_MATCH`, `HIGHEST_PRIORITY`, or `MAX_BENEFIT`
`mutexLimit`	Max number of rules to fire from this group (for EXCLUSIVE)

When mutexMode is EXCLUSIVE, only the winning rule fires. Other matching rules in the same mutex group are skipped. This is logged in the Decision Trace as BLOCKED_BY_MUTEX.

Complete Rule Example

{
  "name": "VIP 20% Discount",
  "priority": 0,
  "condition": {
    "type": "GROUP",
    "operator": "AND",
    "children": [
      { "type": "SINGLE", "field": "customer_tier", "operator": "EQUALS", "value": "VIP", "valueType": "STRING" },
      { "type": "SINGLE", "field": "payment_amount", "operator": "GREATER_THAN_OR_EQUAL", "value": 100000, "valueType": "NUMBER" }
    ]
  },
  "actions": [
    { "type": "DISCOUNT", "parameters": { "method": "PERCENTAGE", "rate": 20, "refVar": "payment_amount" } },
    { "type": "SET_FACT", "parameters": { "key": "discount_applied", "value": true } }
  ],
  "mutexGroup": "best-discount",
  "mutexMode": "EXCLUSIVE",
  "mutexStrategy": "HIGHEST_PRIORITY",
  "isEnabled": true
}

Getting Started

Core Concepts

Features

What is a Policy Rule?

Condition Syntax

SINGLE Condition

GROUP Condition

Operators

Value Types

Nested Conditions Example

Action Types

DISCOUNT — Percentage

DISCOUNT — Fixed Amount

SET_FACT — Output Variable

BLOCK — Transaction Block

POINT — Percentage

POINT — Fixed Amount

COUPON_ISSUE

NOTIFICATION

ADD_TAG

WEBHOOK — Basic

WEBHOOK — With Payload Template

Available Template Variables

Mutex — Rule-Level Conflict Resolution

Complete Rule Example

Next Steps

Fact Definitions

Dry Run

Getting Started

Core Concepts

Features

​What is a Policy Rule?

​Condition Syntax

​SINGLE Condition

​GROUP Condition

​Operators

​Value Types

​Nested Conditions Example

​Action Types

​DISCOUNT — Percentage

​DISCOUNT — Fixed Amount

​SET_FACT — Output Variable

​BLOCK — Transaction Block

​POINT — Percentage

​POINT — Fixed Amount

​COUPON_ISSUE

​NOTIFICATION

​ADD_TAG

​WEBHOOK — Basic

​WEBHOOK — With Payload Template

​Available Template Variables

​Mutex — Rule-Level Conflict Resolution

​Complete Rule Example

​Next Steps

Fact Definitions

Dry Run

What is a Policy Rule?

Condition Syntax

SINGLE Condition

GROUP Condition

Operators

Value Types

Nested Conditions Example

Action Types

DISCOUNT — Percentage

DISCOUNT — Fixed Amount

SET_FACT — Output Variable

BLOCK — Transaction Block

POINT — Percentage

POINT — Fixed Amount

COUPON_ISSUE

NOTIFICATION

ADD_TAG

WEBHOOK — Basic

WEBHOOK — With Payload Template

Available Template Variables

Mutex — Rule-Level Conflict Resolution

Complete Rule Example

Next Steps