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 unverified work being recorded as complete. ## Core Features & Use Cases - Delta Spec Sync: Merges ADDED, MODIFIED, REMOVED, and RENAMED requirements from delta specs into main specs while preserving untouched requirements. - Gate Enforcement: Blocks archiving when the native review receipt is missing, tasks remain unchecked, or CRITICAL verification issues exist. - Multi-Mode Persistence: Supports engram, openspec, hybrid, and none artifact store modes, persisting an archive report with observation IDs for traceability. - Use Case: After an SDD change passes implementation and verification, the orchestrator delegates to this sub-agent to sync specs, move the change folder to openspec/changes/archive/YYYY-MM-DD-{change-name}/, and produce a final-state archive report. ## Quick Start Ask the orchestrator to archive the completed SDD change by delegating to the sdd-archive sub-agent with the change name and artifact store mode.