Set field

Writes a value into a field of the event type.

Configuration	Content
Destination	field of the event type
Value	fixed value or expression, validated according to the field type

It is the most common action, applied to cases such as flagging a transaction for review, classifying an event, or recording the risk band assigned to it.

Condition:  $amount > 10000 and $issuer_country != "BR"
Action:     Set field → review = "true"          (fixed value)

In expression mode, the value written comes from another field, from a temporary variable, or from a join, which makes it possible to carry a result computed during the rule into the event:

Condition:  $amount > 0                    → Run analysis: bot
Condition:  %bot.triggered == true         → Set field: bot_score = %bot.score   (expression)

The value is validated when the rule is saved, according to the destination field’s rules: a numeric field does not accept text, a text field respects the configured size. Fields reserved by the platform (starting with _) cannot be filled in by an action.

When the destination is a boolean field, the fixed value is chosen from a list with the field’s own two labels: you select Blocked, not true. To copy a boolean from somewhere else, such as %bot.triggered, use expression mode.

If two conditions fill in the same field, the last one executed wins.