> ## Documentation Index
> Fetch the complete documentation index at: https://cognitio-agent.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Type Alias: CanUseToolCallback

> Generated from the public TypeScript API.

```ts theme={null}
type CanUseToolCallback = (toolName, input, ctx) =>
  | Promise<PermissionDecision>
  | PermissionDecision;
```

Application permission callback returning allow, deny or ask, optionally with replacement tool input.

## Parameters

### toolName

`string`

### input

`Record`\<`string`, `unknown`>

### ctx

#### rootSessionId?

`string`

#### sessionId

`string`

#### signal

`AbortSignal`

#### toolCallId?

`string`

## Returns

\| `Promise`\<[`PermissionDecision`](https://cognitio-agent.mintlify.site/api-reference/supporting/PermissionDecision)>
\| [`PermissionDecision`](https://cognitio-agent.mintlify.site/api-reference/supporting/PermissionDecision)


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