> ## 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.

# nika:prompt

> Usage, declared contract and source links for this Nika builtin.

export const Ecosystem = () => <CardGroup cols={3}>
    <Card title="Documentation" icon="book" href="/introduction">
      Guides, reference contracts and working examples.
    </Card>
    <Card title="Nika Lab" icon="diagram-project" href="https://github.com/supernovae-st/nika-lab">
      Internal workspace and graph projections of the spec, documentation and code.
    </Card>
    <Card title="Language spec" icon="file-contract" href="https://github.com/supernovae-st/nika-spec">
      the nine-key envelope, Apache-2.0. The contract these docs explain.
    </Card>
    <Card title="Engine source" icon="gem" href="https://github.com/supernovae-st/nika">
      Rust, AGPL-3.0-or-later. Every commit public.
    </Card>
    <Card title="TypeScript SDK" icon="code" href="/sdk/overview">
      Use one typed lifecycle locally or against authenticated nika serve HTTP.
    </Card>
    <Card title="Editor extension" icon="puzzle-piece" href="https://marketplace.visualstudio.com/items?itemName=supernovae.nika-lang">
      VS Code · Cursor · Windsurf: check-as-you-type, DAG view, trace replay.
    </Card>
    <Card title="Homebrew tap" icon="beer-mug-empty" href="https://github.com/supernovae-st/homebrew-tap">
      `brew install supernovae-st/tap/nika` for the latest tagged CLI release.
    </Card>
    <Card title="SuperNovae" icon="star" href="https://supernovae.studio">
      The Paris studio crafting Nika. 🦋
    </Card>
  </CardGroup>;

[Builtins catalog](/reference/builtins) / `nika:prompt`

<CardGroup cols={2}>
  <Card title="Core" icon="layer-group">Tool family from the canonical registry.</Card>
  <Card title="invoke" icon="code" href="/reference/language/words/invoke">Call this builtin through the invoke verb.</Card>
</CardGroup>

## Read this contract

This reference preserves the specification at the revision linked below. Source examples are **fragments**: their surrounding tasks, inputs and permissions are not supplied here. Consult [engine status](/reference/status) and `nika catalog --tools --json` for the installed implementation; a registry declaration is not a runtime qualification.

## Usage and behavior

```yaml illustration theme={"system"}
# confirm (default) — a yes/no gate
invoke: { tool: "nika:prompt", args: { message: "Approve deploy to production?", default: false } }
# input — collect a free-text value
invoke: { tool: "nika:prompt", args: { mode: input, message: "Paste the OTP:", default: "" } }
# choice — pick one of N
invoke: { tool: "nika:prompt", args: { mode: choice, message: "Which title?", choices: ["${{ tasks.a.output }}", "${{ tasks.b.output }}"] } }
```

Interactive human-in-the-loop · blocks until answered. **`mode:` selects what
is collected** (default `confirm`) ·

| `mode`              | Returns     | Notes                                                                                                                         |
| ------------------- | ----------- | ----------------------------------------------------------------------------------------------------------------------------- |
| `confirm` (default) | **boolean** | `true` = confirmed · `false` = refused. A refusal is a VALUE, never an error: gate downstream with `when:`.                   |
| `input`             | **string**  | the free text the human typed (may be empty).                                                                                 |
| `choice`            | **string**  | the chosen element of `choices:` (required · non-empty array). Returns the chosen value (not its index) so it binds directly. |

Non-interactive contract (normative · all modes) · when no human can answer
(CI · daemon) the engine MUST use `default:` when present · and MUST fail
`NIKA-BUILTIN-PROMPT-001` (`validation_error` · non-interactive without a
`default:`) when absent: never hang forever · never silently pick an answer.
A `choice` whose `default:` is not an element of `choices:` is a parse error
(`NIKA-BUILTIN-PROMPT-002` · `validation_error`).

## Related concepts

<CardGroup cols={2}>
  <Card title="Arguments" icon="sliders" href="/reference/language/words/args">Pass the values required by the tool contract.</Card>
  <Card title="Permissions" icon="shield" href="/concepts/security">Understand authority before granting effects.</Card>
  <Card title="Errors and recovery" icon="rotate" href="/reference/error-codes">Read diagnostics and choose a recovery policy.</Card>
  <Card title="Workflow templates" icon="file-code" href="/guides/templates">Put the fragment inside a complete workflow.</Card>
</CardGroup>

## Contract provenance

[Read the pinned specification](https://github.com/supernovae-st/nika-spec/blob/f8c5df2127c7867b2e51a2cd5712fa9d8461e73e/stdlib/builtins-v0.1.md#L90) · [Canonical registry](https://github.com/supernovae-st/nika-spec/blob/f8c5df2127c7867b2e51a2cd5712fa9d8461e73e/canon/builtins.yaml).

Tool identity: `nika:prompt`. Specification revision: `f8c5df2127c7`.
The Lab language identity is `language:tool:prompt`; the registry view is `ecosystem:tool/nika:prompt`. They refer to this contract without merging their graph identities.

<Ecosystem />