> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nika.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# run

> Contract, placement, related fields and source examples for this Nika YAML field.

[Language reference](/reference/language/overview) / `run`

## Meaning and placement

### document

The run's entropy and clock declaration · every source of randomness and of time is declared, never ambient. The two dimensions couple: only `ambient × system` (the status quo) and `none | seeded × virtual` (the deterministic states) are legal, and a declared contradiction refuses at parse (NEP-0010).

| Property             | Declaration             |
| -------------------- | ----------------------- |
| Requirement          | Optional in this object |
| Schema location      | `/properties/run`       |
| type                 | "object"                |
| additionalProperties | false                   |

**In the same object:** [const](/reference/language/words/const) · [inputs](/reference/language/words/inputs) · [model](/reference/language/words/model) · [nika](/reference/language/words/nika) · [outputs](/reference/language/words/outputs) · [permits](/reference/language/words/permits) · [secrets](/reference/language/words/secrets) · [tasks](/reference/language/words/tasks)

[Schema source (use the pointer above)](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/schemas/workflow.schema.json)

## In a source template

Excerpt from `templates/fanout.nika.yaml`, source lines 54–63. This is a fragment, not a runnable workflow.

```yaml illustration theme={"system"}
# stamp leaves `mock/echo`, the offline path this file guarantees.
model: mock/echo

run:
  # A `timeout:` is a deadline, and a deadline needs a clock. Declaring it says
  # out loud which one: `system` is the ambient wall clock (the honest default);
  # `virtual` drives a simulated clock for deterministic tests.
  clock: system

const:
```

### Templates containing this field

| Template                     | Source                                                                                                                             |
| ---------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| `templates/fanout.nika.yaml` | [Line 57](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/fanout.nika.yaml#L57) |

These are literal key occurrences in the source files, not an execution or conformance claim. [How to instantiate a template](/guides/templates).

## Contract and implementation

This page projects the named specification revision. Check [released engine status](/reference/status) and [the validation workflow](/guides/agent-authoring) before running a file. An optional field is not evidence that every engine supports every value.

Canonical identity: `language:word:run`. Spec revision: [`c5ebbb7b862b`](https://github.com/supernovae-st/nika-spec/tree/c5ebbb7b862b68bc6cf7235efba61173b844afc6).

[How documentation stays connected](/reference/knowledge-system).