Chapbook is a confluence of ideas rather than one, wholly original one. Its vars sections are familiar territory to anyone who has used YAML front matter in a static site generator like Hexo. And much of its state-centered design--in opposition to an imperative design, where change occurs mostly through function calls--comes from what I've learned from Redux, the de facto standard library for managing state in the React ecosystem.
You may not be able to tell it by looking at the syntax, but the named hooks of Leon Arnott's Harlowe story format inspired many of the thoughts that Chapbook is based upon. What I found so appealing about named hooks is the idea of keeping code separate from the text it affects; that logic could be kept, if only at arm's length, separate from prose.
Chapbook's default aesthetics owe a lot to the style of the interactive fiction engine Undum, by Ian Millington, as well as Liza Daly's works Stone Harbor and Harmonia. I hope you find Chapbook's appearance half as graceful as these examples. Or if not--I hope I've left you enough hooks to customize it away into something better.
The notes feature of Chapbook's backstage view was inspired by Illume, which is an excellent way to review a Twine story before release.
If you take a look at the Twine Cookbook, you’ll see more than a few similarities between its table of contents and this guide's. This is no accident. One of my design goals with Chapbook was to make common use cases easy--and the Twine Cookbook has been a wonderful signpost as to what people wanted to achieve with Twine.
You might also notice some resemblance between this guide and the Inform Designer's Manual, written by Graham Nelson, which not only is one of my favorite works of technical writing, but is possibly the one document that's most responsible for my ongoing infatuation with interactive fiction.
Finally, I want to thank my creative partner Joel Haddock for patiently playing the roles of guinea pig and sounding board in equal measure.