---
jsApi: true
title: "[T] CadlLibraryDef"

---
```ts
type CadlLibraryDef<T, E>: TypeSpecLibraryDef<T, E>;
```

## Deprecated

Use TypeSpecLibraryDef

## Type parameters

| Parameter | Default |
| :------ | :------ |
| `T` extends `object` | - |
| `E` extends `Record`<`string`, `any`\> | `Record`<`string`, `never`\> |
