> ## 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.

# command

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

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

## Meaning and placement

### exec

argv — the program and its arguments, execve, NO shell. Each element substituted independently (the injection-safe form). Shell features (pipes · redirects · globs) live in `shell:`.

| Property        | Declaration                      |
| --------------- | -------------------------------- |
| Requirement     | Optional in this object          |
| Schema location | `/$defs/exec/properties/command` |
| type            | "array"                          |

**In the same object:** [capture](/reference/language/words/capture) · [cwd](/reference/language/words/cwd) · [decode](/reference/language/words/decode) · [env](/reference/language/words/env) · [shell](/reference/language/words/shell) · [stdin](/reference/language/words/stdin)

[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/docker-report.nika.yaml`, source lines 52–61. This is a fragment, not a runnable workflow.

```yaml illustration theme={"system"}
      # SLOT: argv ARRAY form — one program, exactly these arguments. The array
      # is why there is no shell here: no word-splitting, no globbing, nothing
      # to quote wrong. `permits.exec` above is the provable allowlist.
      command: ["docker", "ps", "--all", "--format", "{{.Names}}\t{{.Status}}\t{{.Image}}"]
    on_error:
      # Offline rehearsal · a host with no daemon answers with a literal that
      # LOOKS like the real thing, so `diagnose` reads the same shape either
      # way. Delete this once the daemon is really there.
      recover: "REHEARSAL\tno docker daemon on this host\tn/a"

```

### Templates containing this field

| Template                               | Source                                                                                                                                         |
| -------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| `templates/docker-report.nika.yaml`    | [Line 55](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/docker-report.nika.yaml#L55)      |
| `templates/human-gated-ship.nika.yaml` | [Line 111](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/human-gated-ship.nika.yaml#L111) |

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:command`. Spec revision: [`c5ebbb7b862b`](https://github.com/supernovae-st/nika-spec/tree/c5ebbb7b862b68bc6cf7235efba61173b844afc6).

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