Contract

The behavior contract remains the source of truth after specification is written. This skill is the discipline of carrying that contract through implementation, verification, and closure without losing traceability.

Lifecycle Role

This skill is cross-cutting, not planning-only. Dropping the behavior contract at any phase breaks traceability.

• Implementation: behavior gaps drive execution order. Each implementation increment maps to one or more behavior statements. Work that cannot be traced to a behavior is unanchored.
• Verification: completion means passing evidence for each claimed behavior, not just "tests pass." Report behavior coverage, not command output.
• Closure: shipped work should still name what behaviors were covered and what gaps remain.

Discipline

Implementation maps to behavior. Every implementation increment connects to one or more behavior statements. If you cannot name which behavior a code change advances, the change is unanchored. This traceability runs the full