New prefill Property for Inputs – Breaking Change for Input defaults

Breaking change

If you have flows with input property defaults, then required can no longer be false. This combination will throw an error, as inputs with a default value must be required. Previously this combination was valid, and any flows with inputs using this configuration must be refactored to one of the below combinations. Inputs using defaults must have required: true.

New prefill Property for Inputs

A new prefill property has been added to input definitions to let users start with an initial value that can be cleared or set to null when the input is not required.

What changed: Inputs can now define a prefill value, which works like an editable default. Unlike defaults, a prefill value does not persist if the user removes it. This allows workflows to support optional inputs that start with a suggestion but can still be reset to null at runtime.

Impact: This update clarifies how required, defaults, and prefill behave together:

• prefill and defaults cannot be used on the same input.
• Use prefill when required: false and the user should be able to clear the value.
• Use defaults when required: true or when the value must always have a non-null default.

To note again, input defaults cannot be used together with required: false.

Example:

inputs:
  - id: nullable_string_with_prefilled_default
    type: STRING
    prefill: "This is a prefilled value you can remove (set to null if needed)"
    required: false

Migration: No migration is required. For optional inputs that previously used defaults but need to allow clearing or null values, switch those definitions to prefill instead.