perhapsspy/purpose-first-design

Purpose-First Design

Job and Exit

Choose the smallest defensible direction for a materially open product or implementation-planning decision before solution structure is fixed. Purpose defines what success means; locked user decisions, authority, and required security, rollback, ownership, and operational boundaries bind the answer and are never alternatives.

End with a provisional direction, the smallest check that could change an actually open choice, or one blocking question. If no material direction remains open, say so briefly and hand off without inventing alternatives.

Decision Contract

• State only the purpose and observable success needed to distinguish the choice.
• Separate decision-relevant inputs into LOCKED, EVIDENCE, ASSUMPTION, and OPEN. Never promote a locked decision, explicit constraint, rejected scope, or evidence-settled item into OPEN. A failed check may change only an unresolved mechanism, not locked product meaning.
• Treat existing implementation, precedent, defaults, and urgency as evidence unless explicitly authoritative. Compare only alternatives that materially change meaning, responsibility, persistent state, policy, lifecycle, public contract, accepted risk, or hard-to-reverse coupling.
• Choose the smallest sufficient direction. Do not add owners, processes, rollback machinery, platforms, future programs, or open decisions unless the source or chosen direction requires them.

Handoff

Use source-owner-audit first when present authority is unknown. Hand settled realization—code flow, state, sequencing, interfaces, failure handling, and implementation order—to structure-first. Hand settled expression and packaging to tighten-docs.

Return a concise decision handoff: direction, decision-changing basis, locked boundaries, real assumptions or open decisions, and the next decisive check or owning workflow. Include a boundary only when it constrains the chosen direction.

Final Reduction

Review only scope, commitments, assumptions, and open decisions introduced by your answer. Remove any that the purpose, locked boundaries, authority, evidence, or chosen direction does not require. Merge alternatives only when their product meaning and required boundaries are the same.

This pass may reduce but must not create scope, commitments, assumptions, open decisions, or handoffs, and must never reopen LOCKED meaning. If it exposes a missing mandatory boundary, state that boundary as required rather than optional. Preserve complexity that is necessary for security, rollback, ownership, operations, or a demonstrated failure mode.