---
url: >-
  https://adk.nht.io/api/@nhtio/adk/exceptions/variables/E_INVALID_INITIAL_TOOL_VALUE.md
description: >-
  Thrown when a {@link @nhtio/adk!Tool} is constructed with a value that fails
  schema validation.
---

# Variable: E\_INVALID\_INITIAL\_TOOL\_VALUE

```ts
const E_INVALID_INITIAL_TOOL_VALUE: CreatedException<[]>;
```

Defined in: [lib/exceptions/runtime.ts:378](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/exceptions/runtime.ts#L378)

Thrown when a [@nhtio/adk!Tool](../../forge/classes/Tool.md) is constructed with a value that fails schema validation.

## Remarks

Fatal — bad construction arguments indicate a programming error in the caller.