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+# Phase 12: Library CRUD & Data Integrity - Context
+
+**Gathered:** 2026-03-12
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Users can add, rename, and remove libraries through the UI with correct data lifecycle management. Tracks are created/deleted, shared entities (artists, albums, genres) are cleaned up only when orphaned, FTS5 search index stays consistent, queue tracks cascade-delete, and playlist tracks convert to phantoms. The library manager UI lives in settings alongside scan controls.
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Library management UI
+- Integrated library + scan section in the settings page — combine library management and scanning into one unified section
+- Remove the libraries tab from the sidebar list entirely
+- Each library row displays: name, directory path, track count in the main row; actions (rename, remove, rescan) hidden behind a `...` overflow menu
+- Replace the old single-directory config UI (directory path field + rescan button) completely — the migrated library appears in the new list
+
+### Add-library flow
+- Click "Add Library" button in the library management section
+- OS folder picker dialog opens
+- Library auto-named from the folder name (editable later via rename)
+- Scan starts automatically after adding
+- Uses the existing per-library scan pipeline from Phase 11
+
+### Removal confirmation & feedback
+- Warning dialog with impact summary before removal: "Remove 'Jazz Collection'? This will delete 1,234 tracks, affect 2 playlists, and remove 15 queue items."
+- If a track from the library being removed is currently playing, stop playback first, then proceed with removal; queue advances to next valid track if one exists
+- Blocking operation with spinner on the dialog while cleanup runs (expected < 1 second for most libraries)
+- Toast notification on completion: "Removed 'Jazz Collection' (1,234 tracks deleted)"
+
+### Orphan cleanup behavior
+- Immediate cleanup in the same database transaction — delete tracks, identify orphaned entities, delete orphans, convert playlist phantoms, all atomic
+- Reference-counting bottom-up: only delete artists/albums/genres that have zero remaining track references after the library's tracks are removed
+- Rebuild the entire FTS5 index from remaining tracks after library removal (handles contentless table limitation cleanly)
+- Playlist phantom track conversion in the same transaction: copy track metadata to phantom columns on playlist_tracks, then SET NULL the audio_file_id
+- Queue tracks cascade-delete (queue is ephemeral, not user-curated)
+- Removal API endpoint returns cleanup summary: {tracks_deleted, artists_removed, albums_removed, genres_removed, playlists_affected, queue_items_removed} — feeds the toast notification
+
+### Rename & display behavior
+- Library names must be unique — validation error if user tries to use an existing name
+- Inline edit on the list row: click name (or rename action from menu) turns it into an editable text field, Enter to save, Escape to cancel
+- Name validation: 1-50 characters, non-empty
+- Rename changes display name only — changing a library's directory path requires remove + add (no path editing)
+
+### Claude's Discretion
+- Exact layout/styling of the library management section within settings
+- Loading skeleton design while library list loads
+- Error state handling for failed operations
+- Exact spinner implementation during removal
+- Toast notification library/component choice
+- API endpoint URL structure and HTTP methods
+- SQL query optimization for orphan detection
+
+</decisions>
+
+<specifics>
+## Specific Ideas
+
+- Library management section should feel like a natural extension of the existing settings page — not a separate app within settings
+- The impact summary in the removal dialog should use real counts from the database, not estimates
+- The `...` overflow menu pattern keeps the list clean — same pattern used elsewhere in the app for action menus
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+None — discussion stayed within phase scope
+
+</deferred>
+
+---
+
+*Phase: 12-library-crud-data-integrity*
+*Context gathered: 2026-03-12*