---
title: isCausal
framework: metalperformanceshadersgraph
role: symbol
role_heading: Instance Property
path: metalperformanceshadersgraph/mpsgraphsdpadescriptor/iscausal
---

# isCausal

When YES, a causal (lower-triangular) mask is applied so that each query position attends only to key positions at or before it. Mutually exclusive with maskTensor.

## Declaration

```swift
var isCausal: Bool { get set }
```