The following app behaviors are incompatible with App Sandbox:
[...]
Use of accessibility APIs in assistive apps
With App Sandbox, you can and should enable your app for accessibility, as described in Accessibility Overview for OS X. However, you cannot sandbox an assistive app such as a screen reader, and you cannot sandbox an app that controls another app.
The following app behaviors are incompatible with App Sandbox:
[...]
Use of accessibility APIs in assistive apps
With App Sandbox, you can and should enable your app for accessibility, as described in Accessibility Overview for OS X. However, you cannot sandbox an assistive app such as a screen reader, and you cannot sandbox an app that controls another app.