Tonality comes with three AUv3 plugins which provide MIDI support for use inside hosts like Audiobus, AUM, and Cubasis. Please note that GarageBand does not currently support MIDI plugins such as these.

The chord/scale identification AU allows you to play a collection of notes and instantly see what chord or scale they could be

You can also click on any chord to view more information

The chord pad AU is a powerful composition and performance tool

Each chord pad is a MIDI trigger. You can select any chord from Tonality's database and edit its voicing (down to the octave and velocity of each note). 

Pads are also MIDI trigger assignable (you can make them sound when a certain MIDI note on message is received).

The tool pad allows you to easily clear, copy/paste, transpose, and invert pads.

Pads can be velocity sensitive and MIDI CCs can be assigned so each becomes a mini XY controller

The Grandstaff AU allows you to view sheet music representation of chords in real time for any MIDI input