> ## 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.

# protocol

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

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

## Meaning and placement

### → run → access

The connection protocol the route MUST use · api (the route's inference API) · acp (an Agent Client Protocol session with an agent application). Only an ACP session satisfies acp: a direct CLI invocation of the same application does not. There is no third value.

| Property | Declaration |
| - | - |
| Requirement | Optional in this object |
| Schema location | `/properties/run/properties/access/properties/protocol` |
| enum | declaration below |

<details>
  <summary><code>enum</code> schema declaration (spec source, not a lesson)</summary>

  ```json theme={"system"}
  [
    "api",
    "acp"
  ]
  ```
</details>

**In the same object:** [fallback](/reference/language/words/fallback) · [via](/reference/language/words/via)

[Schema source (use the pointer above)](https://github.com/supernovae-st/nika-spec/blob/f3a952514b51ce884f42839c627bd88887fc941e/schemas/workflow.schema.json)

## Examples

No matching source-template occurrence is recorded in this projection. [Write a workflow](/guides/templates) or consult the schema declaration above.

## 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:protocol`. Spec revision: [`f3a952514b51`](https://github.com/supernovae-st/nika-spec/tree/f3a952514b51ce884f42839c627bd88887fc941e).

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


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