principle-model-the-domain
Apply when writing stateful logic, or when code branches a lot or repeats a shape assumption across files.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/backnotprop/pstack --skill principle-model-the-domain- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads principle-model-the-domain automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
Security audits
Independent scans of the skill's instructions and bundled files.
SKILL.md
The instructions your agent reads when the skill is triggered.
Model the Domain
Encode the real domain in a data structure instead of scattering it across conditionals. A structure that matches the domain makes invalid states unrepresentable and deletes branches. Choosing it at write time is cheap. Recovering it later reads as a refactor and gets deferred.
Reach for:
- A state machine instead of scattered booleans, phases, or lifecycle checks.
- A typed model instead of loose parameters or repeated shape assumptions.
- A map, registry, lookup table, or discriminated union instead of branching spread across files.
- A reducer or command/event model instead of ad hoc state mutations.
- A module organized around one body of domain knowledge instead of a sequence such as load, validate, transform, and save. Execution order is not ownership.
- A small module boundary that gathers repeated behavior, ownership, or invariants.
- A queue, cache, index, graph, tree, or normalized collection where the access pattern calls for it.
- Any other structure that fits. When none fits, work out what the code must never allow and how the data gets read, then find the structure that encodes exactly that.
Do not force an abstraction. Prefer boring code if the current shape is already clear, local, and unlikely to grow. Be skeptical of an abstraction that adds indirection without removing branches, duplicated rules, invalid states, or lifecycle risk.
The sign that you skipped this is a new feature that grows an existing if/else chain by one more branch, or a second boolean that must stay in sync with the first. Temporal decomposition is another sign. Phase-named modules repeat the same domain rules across steps.
FAQ
What does the principle-model-the-domain skill do?
Apply when writing stateful logic, or when code branches a lot or repeats a shape assumption across files.
How do I install principle-model-the-domain?
Run npx skills add https://github.com/backnotprop/pstack --skill principle-model-the-domain in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/principle-model-the-domain/ (personal) or .claude/skills/principle-model-the-domain/ (project).
Which AI agents can use principle-model-the-domain?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is principle-model-the-domain safe to install?
Security partners have reviewed it: Gen Agent Trust Hub passed; Socket passed; Snyk passed. As with any skill, read the SKILL.md and bundled scripts before installing.
Who maintains principle-model-the-domain?
It is published by backnotprop in backnotprop/pstack. It has 5,434 recorded installs.
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