jarca-ledger-mcp/docs/batches/bat-012_20260703_import-pipeline-split/design.md

BAT-012 Design

Architecture summary

• Introduce jarca_ledger_mcp/application/imports_service.py as the single application-layer home for import preview/import/rollback orchestration.
• Introduce jarca_ledger_mcp/infrastructure/parsers/ as the parser seam so application code no longer imports top-level parser implementations directly.
• Keep current top-level parser modules for compatibility if needed, but route application/shared usage through the infrastructure seam.
• Preserve application/import_transfer_services.py as the advanced workflow home; import-facing public functions become delegations into imports_service.py.

Changed areas

• application import orchestration
• infrastructure parser seam
• service export surface / compatibility proxy
• import regression verification docs

Key decisions

1. Parser relocation is seam-first, not algorithm rewrite.
2. Import account auto-linking/classification stays in the application layer, not in parser modules.
3. Public API/tool names remain unchanged.

Verification focus

• Import preview/import/rollback regression
• Evidence field preservation
• No breakage in MCP discovery and public exports