Skip to content
appsgit

Principle Type System Discipline

Principle Type System Discipline is an agent skill (a SKILL.md file) from backnotprop/pstack. Apply when designing types, reviewing a function signature, or writing code in any statically-typed language. It works with Claude Code, Codex, Cursor and OpenCode and has 1,172 GitHub stars across a repository of 2 listed skills.

github.com/backnotprop/pstack/skills/principle-type-system-discipline (opens in a new tab)

View on GitHub (opens in a new tab)

Add this skill

Claude

Claude Code loads skills from ~/.claude/skills/ (all projects) or .claude/skills/ (one project):

git clone --depth 1 https://github.com/backnotprop/pstack.git
cp -r pstack/skills/principle-type-system-discipline ~/.claude/skills/principle-type-system-discipline   # personal, or .claude/skills in a project

In the Claude apps, zip the principle-type-system-discipline folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

ChatGPT / Codex

Codex reads skills from .agents/skills/ in a repo or ~/.agents/skills/ for every project:

git clone --depth 1 https://github.com/backnotprop/pstack.git
cp -r pstack/skills/principle-type-system-discipline .agents/skills/principle-type-system-discipline   # repo; ~/.agents/skills for all projects

Standalone skills also load in the ChatGPT desktop app.

Cursor

Cursor loads skills from .cursor/skills/ (or ~/.cursor/skills/) and also reads .claude/skills/:

git clone --depth 1 https://github.com/backnotprop/pstack.git
cp -r pstack/skills/principle-type-system-discipline .cursor/skills/principle-type-system-discipline   # project; ~/.cursor/skills for all projects

Source (checked Oct 7, 2026): code.claude.com/docs/en/skills (opens in a new tab), support.claude.com/en/articles/12512180-using-skills-in-claude (opens in a new tab), learn.chatgpt.com/docs/build-skills (opens in a new tab), cursor.com/docs/context/skills (opens in a new tab)

What this skill does

Apply when designing types, reviewing a function signature, or writing code in any statically-typed language. Make illegal states unrepresentable, brand semantic primitives, parse external data at boundaries, refuse to lie to the compiler, exhaust variants, derive from authoritative schemas. The type checker is a proof assistant. Use it to eliminate impossible states, mismatched primitives, and unhandled variants at compile time.

More skills in backnotprop/pstack

2 skills are listed from this repository.

Similar skills

More docs & writing skills

All Docs & writing

FAQ

Principle Type System Discipline FAQ

Still curious? Email info@appsgit.com.

What is the Principle Type System Discipline skill?

Principle Type System Discipline is an agent skill (a SKILL.md file) from backnotprop/pstack. Apply when designing types, reviewing a function signature, or writing code in any statically-typed language. It works with Claude Code, Codex, Cursor and OpenCode and has 1,172 GitHub stars across a repository of 2 listed skills. Its SKILL.md lives at github.com/backnotprop/pstack/skills/principle-type-system-discipline.

How do I install the Principle Type System Discipline skill?

Copy the principle-type-system-discipline folder (the one containing SKILL.md) into ~/.claude/skills/ for Claude Code, .agents/skills/ for Codex or .cursor/skills/ for Cursor. The agent picks it up automatically when a task matches its description.

Is the Principle Type System Discipline skill free?

Yes. The repository is open source under the MIT license.

Is Principle Type System Discipline maintained?

The repository's most recent commit was on Oct 4, 2026. appsgit only lists skills from repositories with a commit in the last six months.