Backend

Java/Spring in backend/src/main/java/com/odde/donut/. Tests under backend/src/test/. Schema changes: db-migration skill.

Matching backend-code (production Java) and backend-testing (tests) skills attach via paths when those files are in context — do not fetch them up front.

Commands

CURSOR_DEV=true nix develop -c pnpm backend:test_only

When a database migration is involved:

CURSOR_DEV=true nix develop -c pnpm backend:verify

Always run all backend unit tests, not a selected file or test case.

Production

• Controllers: return entities (or existing API body types). Narrow with @JsonIgnore / @JsonView. Introduce a response DTO only when the wire shape differs.
• Top-of-file imports. No inline fully qualified class names except when two types share a simple name.
• After Flyway schema changes, regenerate docs/database-erd.md with the database-erd skill (pnpm export:database-erd).
• Note collections name their trash semantics. NoteRepository.findAllByNotebookIdOrderByIdAsc is the complete stored content, trash included (export, Git snapshots, learning-session title recognition); findAvailableNotesByNotebookIdOrderByIdAsc and the Note.JPA_AVAILABLE / NATIVE_AVAILABLE predicates select participating notes (search, recall, health rules); findOccupiedFolderIdsByNotebookId counts stored content for folder occupancy. On a loaded Note, isTrashed() follows current folder ancestry and isTrashedInDatabase() is the persisted membership as loaded. Root _trash membership is owned by Folder.isTrashed and the trashed_folder view; do not recreate the rule in callers.

Tests

Small-test style (unit-testing skill): prefer controller (HTTP-stable-boundary) tests; cover services/repos via realistic makeMe preconditions and the real DB (@Transactional). Test a service/algorithm directly only when it is an intentional domain-stable contract.

Mock only external services — OpenAIClient via OpenAiStructuredResponseMock. Ownership: notebookOwnedBy(user) so trackers inherit the owner. Group with @Nested.