when

Language reference / when

Meaning and placement

task

LOCAL business condition · false skips the task · evaluated after the gate and BEFORE any fan-out, over inputs · const · with only: the for_each locals item / index are not bound yet (NIKA-VAR-001), and a tasks.* reference is refused (NIKA-VAR-021 · hoist it into with:) · spec/03-dag.md §when.

Property	Declaration
Requirement	Optional in this object
Schema location	`/$defs/task/properties/when`

In the same object: after · agent · exec · extract · for_each · group · infer · invoke · lift · on_error · retry · returns · timeout · with Schema source (use the pointer above)

In a source template

Excerpt from templates/corpus-qa.nika, source lines 93–102. This is a fragment, not a runnable workflow.

illustration

  answer:
    with:
      hits: ${{ tasks.retrieve.output }}
    when: ${{ size(with.hits) > 0 }}
    infer:
      # a reasoning model needs 16384 here, or a documented run.reasoning.effort: low
      max_tokens: 500                # SLOT: answer spend ceiling
      prompt: |
        Answer from these passages only and cite their ids.
        Question: ${{ const.query }}

Templates containing this field

Template	Source
`templates/corpus-qa.nika`	Line 96
`templates/etl-state.nika`	Line 102
`templates/gate-and-act.nika`	Line 70
`templates/human-gated-ship.nika`	Line 147

These are literal key occurrences in the source files, not an execution or conformance claim. How to instantiate a template.

Contract and implementation

This page projects the named specification revision. Check released engine status and the validation workflow before running a file. An optional field is not evidence that every engine supports every value. Canonical identity: language:word:when. Spec revision: 5c40ba456c53. How documentation stays connected.

YAML

Language fields

CLI & errors

Data catalogs

Workspace

Documentation system

Tool contracts

Meaning and placement

task

In a source template

Templates containing this field

Contract and implementation

​Meaning and placement

​task

​In a source template

​Templates containing this field

​Contract and implementation

Meaning and placement

task

In a source template

Templates containing this field

Contract and implementation