The idea is to let you explore different sides of an argument, or different sides of your psyche. For example, you might choose the three characters, "optimist", "pessimist" and "judge" to hold a group conversation that looks like a mobile phone chat, as a way to work through a difficult challenge in life that needs reflection and long-form thought.
The reason I'm building this is I find that I often don't complete a thought before negating myself--I cut short embarrassing or superficially trivial feelings, but I believe they sometimes deserve more stage time. Sometimes it's exploring thoughts that relate to uncomfortable feelings that yield the highest return on time spent.
Soliloquy is being built with neutralinojs, so it will work on any desktop OS (Mac/Linux/Window). It is "local only"--no network connection, so you can rest assured your private conversations are your own. I intend to publish it with MIT license but haven't got around to that yet :)