> ## 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.

# args

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

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

## Meaning and placement

### invoke

Arguments passed to the tool · an object whose shape is the TOOL's own schema, not the language's. Each builtin and each MCP tool declares its own (spec/02-verbs.md §invoke) · `${{ }}` may appear in any leaf value.

| Property        | Declaration                     |
| --------------- | ------------------------------- |
| Requirement     | Optional in this object         |
| Schema location | `/$defs/invoke/properties/args` |
| type            | "object"                        |

**In the same object:** [tool](/reference/language/words/tool) · [workflow](/reference/language/words/workflow)

[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/agent-loop.nika.yaml`, source lines 138–147. This is a fragment, not a runnable workflow.

```yaml illustration theme={"system"}
      has_findings: ${{ size(tasks.execute.output.findings) > 0 }}   # the check crosses as ONE boundary expression · SLOT: your law
    invoke:
      tool: "nika:assert"
      args:
        condition: "${{ with.has_findings }}"
        message: "Agent returned no findings, do not trust an empty run"   # SLOT

outputs:
  findings:
    value: ${{ tasks.execute.output.findings }}
```

### Templates containing this field

| Template                                    | Source                                                                                                                                            |
| ------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
| `templates/agent-loop.nika.yaml`            | [Line 141](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/agent-loop.nika.yaml#L141)          |
| `templates/api-upload-and-create.nika.yaml` | [Line 71](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/api-upload-and-create.nika.yaml#L71) |
| `templates/chain.nika.yaml`                 | [Line 49](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/chain.nika.yaml#L49)                 |
| `templates/classify-and-route.nika.yaml`    | [Line 97](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/classify-and-route.nika.yaml#L97)    |
| `templates/corpus-qa.nika.yaml`             | [Line 35](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/corpus-qa.nika.yaml#L35)             |
| `templates/docker-report.nika.yaml`         | [Line 93](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/docker-report.nika.yaml#L93)         |
| `templates/document-to-fields.nika.yaml`    | [Line 41](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/document-to-fields.nika.yaml#L41)    |
| `templates/etl-state.nika.yaml`             | [Line 73](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/etl-state.nika.yaml#L73)             |
| `templates/fanout.nika.yaml`                | [Line 89](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/fanout.nika.yaml#L89)                |
| `templates/gate-and-act.nika.yaml`          | [Line 54](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/gate-and-act.nika.yaml#L54)          |
| `templates/human-gated-ship.nika.yaml`      | [Line 96](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/human-gated-ship.nika.yaml#L96)      |
| `templates/media-asset-pack.nika.yaml`      | [Line 74](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/media-asset-pack.nika.yaml#L74)      |
| `templates/website-brief.nika.yaml`         | [Line 53](https://github.com/supernovae-st/nika-spec/blob/c5ebbb7b862b68bc6cf7235efba61173b844afc6/templates/website-brief.nika.yaml#L53)         |

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

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