What problem does it solve? Closing out a spec-driven development change requires merging delta specifications into the source-of-truth specs and moving the change folder into an audit archive, which is error-prone when done manually and risks stale task states or lost traceability. ## Core Features & Use Cases - Delta Spec Sync: Merges ADDED, MODIFIED, REMOVED, and RENAMED requirements from delta specs into main specs while preserving untouched requirements. - Gated Archiving: Enforces a Native Review Receipt Gate and Task Completion Gate so changes with unchecked tasks or CRITICAL verification issues cannot be archived. - Multi-Mode Persistence: Supports engram, openspec, hybrid, and none artifact store modes, producing a mandatory archive report with observation IDs for traceability. - Use Case: After a feature change has been implemented and verified, the orchestrator delegates to this sub-agent to sync specs, move the change folder to openspec/changes/archive/YYYY-MM-DD-{change-name}/, and persist the final archive report. ## Quick Start Delegate to the sdd-archive sub-agent with the change name and artifact store mode to sync delta specs and archive the completed change.