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name: skill-027 description: "Verify 100% specification closure before Big Bang 80/20 single-pass construction."

Big Bang 80/20: Specification Closure

Core Concept

Specification closure is the gate before EPIC 9 fan-out.

No implementation begins without closure verification.

Closure Checklist

A specification is closed when:

• All inputs characterized (domain, constraints, edge cases)
• All outputs specified (behavior, invariants, success criteria)
• All errors enumerated (what happens when things fail)
• All ambiguities resolved (no TBD, TODO, undefined)
• All user stories have acceptance scenarios
• SHACL validation passes

Quick Validation

# Check for incomplete markers
grep -r "TBD\|TODO\|FIXME\|undefined" .specify/

# Validate SHACL conformance
cargo make speckit-validate

Reference

See CLAUDE.md sections:

• Three Paradigms (Big Bang 80/20)
• When to Use EPIC 9
• Agents: bb80-specification-validator