jarca-ledger-mcp/docs/batches/bat-011_20260703_transactional-write-service-split/planning.md

BAT-011 Planning

Scope

• Implement REQ-015: transactional write path(account / transaction / budget / category rule-category mutation)를 더 좁은 write-oriented application module로 분리한다.
• Preserve top-level service facade, MCP adapter, Streamlit gateway, dashboard call signatures and response envelope contracts.
• Leave import/advanced workflow split for follow-up REQ/BAT under dcy-011.

Dependencies

• dcy-011 confirmed Discovery and Approved REQ-015.
• BAT-010 application/adapters baseline.
• Existing pytest regression and contract-sensitive tests.

Work plan

1. Create write-oriented application modules for accounts / transactions / budgets / category rules.
2. Move concrete mutation implementations into those modules and keep existing broad modules as compatibility delegation layers where needed.
3. Update application/__init__.py and service.py import surface to re-export the new modules without changing public API.
4. Run focused syntax + regression validation, then full pytest if focused checks remain green.
5. Update batch implementation/verification evidence and promote REQ/BAT state if ACs are satisfied.

Design Gate

• Result: standard batch 유지.
• Reason: package boundary 변경, compatibility delegation, category/account/transaction write contract preservation, regression evidence 정리가 함께 필요하므로 planning/design/verification depth가 필요하다.

Risks and mitigations

• Hidden import coupling after write extraction: mitigate by preserving re-export layers and running full pytest.
• Envelope drift on mutation responses: mitigate by preserving existing function signatures and contract-sensitive tests.
• Category rule/category mutation helpers may still share read-side helpers: mitigate by extracting only write-focused logic first and leaving broad read/report paths untouched in this batch.