Customize DEX alert events

task brazil Updated Oct 23, 2026 2 min read customize-dex-alert-events.md

Apply your organization's own event processing rules, such as enrichment or routing, by transforming DEX metric rule events with a custom script before they're processed.

Before you begin

Role required: sn_dex.admin

The Application and Device Health plugin (com.sn_dex) version 5.3.0 or later must be installed.

About this task

By default, DEX processes metric rule events through a fixed pipeline for alerts, proactive engagement, and remedial actions. If your organization has its own event processing rules, you can use the sn_dex.DEXMetricRuleEventExtension extension point to modify each event before DEX processes it. For example, you can enrich events with extra data or change how they're routed.

You customize events by creating a script include that implements a transform(event) method, and then registering that script include as an implementation of the extension point.

You can't customize the following event properties. They're read-only because DEX alert processing depends on them.

severity
message_key
time_of_event
source
resource
classification
type
metric_name

Procedure

Navigate to All > System Definition > Script Includes and select New.
In the Name field, enter a name for your customization script.

The name must match the type value in your script. The example in the next step uses TestMetricRuleExtensionImp.
In the Script field, define a transform(event) method that modifies the event and returns it.

Change only properties that aren't in the read-only list. The following example returns the event unchanged. Add your enrichment or routing logic before the return statement.
JavaScript
```
var TestMetricRuleExtensionImp = Class.create();TestMetricRuleExtensionImp.prototype = {    initialize: function() {    },
    transform : function(event) {        return event;    },
    type: 'TestMetricRuleExtensionImp'};
```
Select Submit.
Create an extension instance for the sn_dex.DEXMetricRuleEventExtension extension point.
1. In the Point field, enter sn_dex.DEXMetricRuleEventExtension.
2. In the Class field, select the script include you created.
3. In the Order field, enter the processing order for this implementation.
4. Select the Active check box.
5. Select Submit.

Result

DEX runs your transform(event) method on metric rule events before it processes them for alerts.

What to do next

For information about the rules that generate these events, see Create metric rules.

Keywords customize dex alert eventsmetric rule event extensionDEXMetricRuleEventExtensionextension pointtransform eventevent enrichmentevent routingread-only event properties

92 lines · 3.6 KB Wrap lines

---
title: Customize DEX alert events
description: Apply your organization's own event processing rules, such as enrichment or routing, by transforming DEX metric rule events with a custom script before they're processed.
locale: en-US
canonical_url: https://www.servicenow.com/docs/r/it-operations-management/digital-end-user-experience-dex/customize-dex-alert-events.html
release: brazil
product: Digital End-User Experience \(DEX\)
classification: digital-end-user-experience-dex
topic_type: task
last_updated: "2026-10-23"
reading_time_minutes: 2
keywords: [customize dex alert events, metric rule event extension, DEXMetricRuleEventExtension, extension point, transform event, event enrichment, event routing, read-only event properties]
breadcrumb: [Managing alert rules, Configure, Digital End-User Experience, IT Operations Management]
---

# Customize DEX alert events

Apply your organization's own event processing rules, such as enrichment or routing, by transforming DEX metric rule events with a custom script before they're processed.

## Before you begin

Role required: sn\_dex.admin

The Application and Device Health plugin \(com.sn\_dex\) version 5.3.0 or later must be installed.

## About this task

By default, DEX processes metric rule events through a fixed pipeline for alerts, proactive engagement, and remedial actions. If your organization has its own event processing rules, you can use the sn\_dex.DEXMetricRuleEventExtension extension point to modify each event before DEX processes it. For example, you can enrich events with extra data or change how they're routed.

You customize events by creating a script include that implements a `transform(event)` method, and then registering that script include as an implementation of the extension point.

You can't customize the following event properties. They're read-only because DEX alert processing depends on them.

-   `severity`
-   `message_key`
-   `time_of_event`
-   `source`
-   `resource`
-   `classification`
-   `type`
-   `metric_name`

## Procedure

1.  Navigate to **All** &gt; **System Definition** &gt; **Script Includes** and select **New**.

2.  In the **Name** field, enter a name for your customization script.

    The name must match the `type` value in your script. The example in the next step uses `TestMetricRuleExtensionImp`.

3.  In the **Script** field, define a `transform(event)` method that modifies the event and returns it.

    Change only properties that aren't in the read-only list. The following example returns the event unchanged. Add your enrichment or routing logic before the `return` statement.

    ```
    var TestMetricRuleExtensionImp = Class.create();
    TestMetricRuleExtensionImp.prototype = {
        initialize: function() {
        },
    
        transform : function(event) {
            return event;
        },
    
        type: 'TestMetricRuleExtensionImp'
    };
    ```

4.  Select **Submit**.

5.  Create an extension instance for the sn\_dex.DEXMetricRuleEventExtension extension point.

    1.  In the **Point** field, enter `sn_dex.DEXMetricRuleEventExtension`.

    2.  In the **Class** field, select the script include you created.

    3.  In the **Order** field, enter the processing order for this implementation.

    4.  Select the **Active** check box.

    5.  Select **Submit**.


## Result

DEX runs your `transform(event)` method on metric rule events before it processes them for alerts.

## What to do next

For information about the rules that generate these events, see [Create metric rules](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/brazil/markdown/it-operations-management/metric-intelligence/create-metric-rules.md).