Open source alternatives to principle-model-the-domain

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principle-model-the-domain

Apply when writing stateful logic

principle-model-the-domain is an agent skill from Cursor's plugins collection that applies a working principle to stateful logic, and to code that branches heavily or repeats an assumption about a shape across files. The principle is to encode the real domain in a data structure instead of scattering it across conditionals. A structure that matches the domain makes invalid states impossible to represent and removes branches. Choosing it when writing the code is cheap, whereas recovering it later reads as a refactor and tends to be deferred. The skill lists the structures to reach for: a state machine in place of scattered booleans, phases or lifecycle checks; a typed model in place of loose parameters and repeated shape assumptions; a map, registry, lookup table or discriminated union in place of branching spread across files; a reducer or command and event model in place of ad hoc state changes; and a module organised around one body of domain knowledge rather than around the order of steps such as load, validate, transform and save. It makes the point that execution order is not ownership. It also suggests a small module boundary that gathers repeated behaviour or invariants. The skill helps when a feature keeps growing new boolean flags or when the same case analysis is repeated in several files. It is listed on skills.sh, where the page shows install counts and GitHub stars for the Cursor plugins repository. Install it with npx skills add https://github.com/cursor/plugins --skill principle-model-the-domain.