Claude-skill-registry bb80-invariant-construction

Extract invariants from specification, encode in types/structure, enable single-pass construction.

install

source · Clone the upstream repo

git clone https://github.com/majiayu000/claude-skill-registry

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/majiayu000/claude-skill-registry "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/data/bb80-invariant-construction" ~/.claude/skills/majiayu000-claude-skill-registry-bb80-invariant-construction && rm -rf "$T"

manifest: skills/data/bb80-invariant-construction/SKILL.md

Big Bang 80/20: Invariant Construction

Core Concept

Big Bang 80/20 means single-pass construction in low-entropy domains.

Key: Extract invariants from specification, encode in types, never violate.

What Are Invariants?

Invariants are properties that must always be true:

Domain	Invariant	Rust Type
Error handling	All errors Result<T,E>	`Result<T, Error>`
File paths	No traversal	`SafePath` wrapper
Age	0 ≤ age ≤ 150	`newtype Age(u8)`
Cache size	≤ 10,000 entries	`BoundedCache<T>`

Type-Safe Design

// ✅ Invariant encoded in type
pub struct Age(u8);  // 0-255 enforced by type

impl Age {
    pub fn new(value: u8) -> Result<Self, Error> {
        if value > 150 {
            Err(Error::InvalidAge)
        } else {
            Ok(Age(value))
        }
    }
}

Reference

See CLAUDE.md sections:

Constitutional Rules (Type-First)
Automatic (Type-safe design)
Holographic Factory Metaphor (Corollary)