Not OP, but the system is described at [0], and apparently hasn't been released yet. Code for this particular story appears to be available at [1], although:
> This code depends on package:egamebook which is not yet open source. Until that happens, you won't be able to build this project unless you're part of the development team (reach out to filiphracek@ if you're interested).
> This code depends on package:egamebook which is not yet open source. Until that happens, you won't be able to build this project unless you're part of the development team (reach out to filiphracek@ if you're interested).
[0] https://egamebook.com/
[1] https://github.com/filiph/edgehead