Deviations
A deviation is governed traffic that does not match the namespace definition you entered for its tag or asset in Contextualize. Each connected broker detects deviations in its own traffic and reports these events to the platform.
Deviations help you track what is happening across your Unified Namespace.
| The Analyze view has two tabs: Data Health and Deviations. This page describes the Deviations tab. For the Data Health tab, see Data Health. |
Review Deviations per Broker
Brokers detect deviations only on active tags and assets. The Deviations tab lists deviations for one broker at a time. If the project has no broker that supports deviations, the tab shows an introduction and an option to connect a broker.
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To review deviations for a broker, click the broker selector above the list to expand the broker table.
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In the table, select the connected broker that you want to review.
The selector supports search and page navigation. For details, see Select a Broker.
Use the filter to narrow the list. Use the Active and Ignored toggle to switch between current deviations and deviations that you previously ignored.
If no deviations match the selected broker, filter, and state, the list shows an empty result. A progress indicator appears while the request runs. For a longer request, the panel shows an additional message about data from the broker. If a request fails or times out, check the broker connection and click the refresh control to retry.
Each row describes one deviation:
| Column | Description |
|---|---|
Node |
The tag or asset whose traffic deviates. For example, a |
Agent |
The connected broker that detected and reported the deviation. |
Issue Type |
The kind of deviation, such as Unexpected Format. See Deviation Types. |
Count |
The number of times the deviation occurred. |
Last Occurrence |
The time when the broker last observed the deviation. |
Actions |
Open the deviation Details, view the tag or asset in the namespace, ignore the deviation, or remove the deviation. |
| In the Agent column, "agent" refers to the broker that reports the deviation, not to an AI agent in Act. |
Inspect a Deviation
To open the Deviation Details view, click Details on a deviation. The view shows the context of the deviation and the payloads that caused it:
| Field | Description |
|---|---|
Namespace |
The breadcrumb path of the tag or asset. For example, |
MQTT Topic |
The full MQTT topic that carries the deviating traffic. |
Issue Type |
The type of deviation. See Deviation Types. |
Occurrence Count |
The number of times the deviation occurred. |
Last Occurred |
The time when the broker last observed the deviation. |
Expected Data Type |
The data type the tag or asset expects. For example, |
Last Valid Payload |
The most recent payload that matched the definition. For example, |
Incorrect Payload |
The payload that triggered the deviation. For example, |
To find the cause of a deviation, compare the Last Valid Payload with the Incorrect Payload.
In this example, the temperature tag expects a Decimal such as 24.0.
The device sometimes sends a string with a unit character, such as 23.6C.
The string does not match the expected data type, so the broker reports an Unexpected Format deviation.
The Deviation Details view also includes the View in Namespace, Ignore, and Remove actions.
Ignore Deviations
Not every deviation needs action. When a deviation is expected or acceptable, you can ignore it so it no longer clutters the active list. For example, a legacy device you plan to migrate later.
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To ignore a deviation, select Ignore on the deviation row or in the Deviation Details view.
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Ignored deviations move out of the Active list. Switch the toggle from Active to Ignored to review everything you have suppressed.
HiveMQ stores an ignore rule for the combination of tag or asset and deviation type. While an ignore is in place, HiveMQ does not show matching deviations on that tag or asset in the Active list.
To stop ignoring a deviation, open the Ignored list and delete it there. HiveMQ removes the ignore rule. If the issue occurs again, the broker detects the deviation and shows it in the Active list.
| Ignore suppresses a deviation and retains its record. Remove deletes an active deviation. The broker detects a removed deviation again if the issue recurs. |
An ignored deviation rule applies to governed traffic only. An ignore rule is different from an ignored topic in Discovery. An ignored topic is excluded from governance completely.
Deviation Types
Every deviation has one of the following types:
| Issue Type | Description |
|---|---|
Missing Field |
A field defined for the tag or asset in the namespace is not present in the payload. |
Unexpected Field |
The payload contains a field that is not defined for the tag or asset in the namespace. |
Unexpected Format |
A value does not match the expected data type or format. For example, a |