Using generative fill with actionJSON

I have been editing an image with the Photoshop API's actionJSON. The actionJSON object has a gaussianBlur and then does a generative AI fill. The call to https://image.adobe.io/pie/psdService/actionJSON is successful, but only the blur is applied to the image, while the generative fill action is nowhere to be seen. Is it not possible to access the generative fill through actionJSON?