---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/artifacts/variables/E_TOON_PEER_MISSING.md
description: Thrown when the TOON peer dependency cannot be loaded.
---

# Variable: E\_TOON\_PEER\_MISSING

```ts
const E_TOON_PEER_MISSING: CreatedException<[string]>;
```

Defined in: [src/batteries/artifacts/toon/exceptions.ts:22](https://github.com/NHTIO/ADK/blob/v1.20260907.0/src/src/batteries/artifacts/toon/exceptions.ts#L22)

Thrown when the TOON peer dependency cannot be loaded.

## Remarks

The @toon-format/toon package is an optional peer. If it is not installed, methods requiring
it throw this exception with installation instructions. The message template includes the package
name, a description of its purpose, the underlying error, and the exact install command, so the
consumer sees a complete, actionable message regardless of call site.