An electronic device, in response to detecting occurrence of a first condition at the device, generates a first alert that corresponds to a respective application in a first class of applications, the first alert including: a first haptic component and a first audio component composed from an audio waveform that is designated for use by the respective application in the first class of applications. In response to detecting occurrence of a second condition at the device, the device generates a second alert that corresponds to a respective application in a second class of applications different from the first class of applications, the second alert including: a second haptic component and a second audio component composed from an audio waveform that is designated for use by applications in the second class of applications.