# Design plan template ```markdown # Written against: ## Evidence chain - Surface: `` - Problem: - Design evidence: `` - Owner: `` - Scope and affected surfaces: `` - Uncertainty: ## Design decision ## Reuse - `` - Exemplar: `` If a new primitive is required, state why the existing system cannot express the decision, where the primitive belongs, and which consumers should share it. ## Changes 1. `` - Change: - Preserve: - Verify: ## Scope - Inherit: - Verify: - Exclude: ## Validation - Product: - Interface: - System: - Repository: `` → ## Stop conditions - Stop if . ## Design documentation - After acceptance and validation: ```