diff --git a/src/lib/api/library.ts b/src/lib/api/library.ts
index 305e1aff..ec3223e6 100644
--- a/src/lib/api/library.ts
+++ b/src/lib/api/library.ts
@@ -1,945 +1,15 @@
 /**
  * Typed wrappers around the `library_*` Tauri commands (spec §7.1) plus
- * subscribers for `library:sync-progress` / `library:sync-idle` events
- * (§7.2). One thin file per cucadmuh's PR-5 kickoff Q1 — Settings UI
- * (LibraryTab) imports from here; nothing else in the app talks to the
- * backend library surface directly.
+ * subscribers for `library:sync-progress` / `library:sync-idle` events (§7.2).
+ *
+ * Formerly one thin file (cucadmuh's PR-5 kickoff Q1); split by concern under
+ * `library/` for the ~500 LOC ceiling. This barrel keeps `@/lib/api/library` as
+ * the single import point, so the Settings UI (LibraryTab) and every other
+ * consumer are unchanged. The private server-id↔index-key helpers live in
+ * `library/internal` and are intentionally not re-exported.
  */
-
-import { invoke } from '@tauri-apps/api/core';
-import { listen, type UnlistenFn } from '@tauri-apps/api/event';
-import { useAuthStore } from '@/store/authStore';
-import { serverIndexKeyFromUrl } from '@/lib/server/serverIndexKey';
-import { resolveServerIdForIndexKey } from '@/lib/server/serverLookup';
-
-// ── DTO mirrors (camelCase, matching the Rust `#[serde(rename_all = "camelCase")]`) ─
-
-export interface TrackRefDto {
-  serverId: string;
-  trackId: string;
-  contentHash?: string | null;
-}
-
-/** E3 readiness summary — present only on single-track `libraryGetTrack` reads. */
-export interface TrackEnrichmentDto {
-  waveformReady: boolean;
-  loudnessReady: boolean;
-  lyricsCached: boolean;
-}
-
-export interface LibraryTrackDto {
-  serverId: string;
-  id: string;
-  contentHash?: string | null;
-  title: string;
-  titleSort?: string | null;
-  artist?: string | null;
-  artistId?: string | null;
-  album: string;
-  albumId?: string | null;
-  albumArtist?: string | null;
-  durationSec: number;
-  trackNumber?: number | null;
-  discNumber?: number | null;
-  year?: number | null;
-  genre?: string | null;
-  suffix?: string | null;
-  bitRate?: number | null;
-  sizeBytes?: number | null;
-  coverArtId?: string | null;
-  starredAt?: number | null;
-  userRating?: number | null;
-  playCount?: number | null;
-  playedAt?: number | null;
-  serverPath?: string | null;
-  libraryId?: string | null;
-  isrc?: string | null;
-  mbidRecording?: string | null;
-  bpm?: number | null;
-  /** `'analysis'` | `'tag'` — Advanced Search BPM dual-storage projection only. */
-  bpmSource?: string | null;
-  replayGainTrackDb?: number | null;
-  replayGainAlbumDb?: number | null;
-  serverUpdatedAt?: number | null;
-  serverCreatedAt?: number | null;
-  syncedAt: number;
-  /** E3: populated only by `libraryGetTrack` (omitted on list/batch reads). */
-  enrichment?: TrackEnrichmentDto | null;
-  rawJson: unknown;
-}
-
-export interface SyncStateDto {
-  serverId: string;
-  libraryScope: string;
-  syncPhase: string;
-  capabilityFlags: number;
-  libraryTier: string;
-  lastFullSyncAt?: number | null;
-  lastDeltaSyncAt?: number | null;
-  nextPollAt?: number | null;
-  serverLastScanIso?: string | null;
-  indexesLastModifiedMs?: number | null;
-  artistsLastModifiedMs?: number | null;
-  ignoredArticles?: string | null;
-  localTrackCount?: number | null;
-  serverTrackCount?: number | null;
-  lastError?: string | null;
-  localTracksMaxUpdatedMs?: number | null;
-  /** True when at least one non-deleted track exists locally (cheap EXISTS). */
-  hasLocalTracks?: boolean;
-  ingestStrategy?: string | null;
-  ingestPhase?: string | null;
-  /** Tracks ingested per persisted initial-sync cursor (IS-3 progress). */
-  cursorIngestedCount?: number | null;
-  n1BulkUnreliable?: boolean | null;
-}
-
-export interface LibraryTracksEnvelope {
-  tracks: LibraryTrackDto[];
-  total: number;
-}
-
-export interface TrackArtifactDto {
-  serverId: string;
-  trackId: string;
-  artifactKind: string;
-  format: string;
-  sourceKind: string;
-  sourceId: string;
-  language?: string | null;
-  contentText?: string | null;
-  contentBytes: number;
-  notFound: boolean;
-  contentHash?: string | null;
-  fetchedAt: number;
-  expiresAt?: number | null;
-}
-
-export interface ArtifactInputDto {
-  artifactKind: string;
-  format: string;
-  sourceKind: string;
-  sourceId: string;
-  language?: string | null;
-  contentText?: string | null;
-  contentBlob?: number[] | null;
-  contentBytes?: number;
-  notFound?: boolean;
-  contentHash?: string | null;
-  expiresAt?: number | null;
-}
-
-export interface TrackFactDto {
-  serverId: string;
-  trackId: string;
-  factKind: string;
-  valueReal?: number | null;
-  valueInt?: number | null;
-  valueText?: string | null;
-  unit?: string | null;
-  sourceKind: string;
-  sourceId: string;
-  confidence: number;
-  contentHash?: string | null;
-  fetchedAt: number;
-  expiresAt?: number | null;
-}
-
-export interface FactInputDto {
-  factKind: string;
-  valueReal?: number | null;
-  valueInt?: number | null;
-  valueText?: string | null;
-  unit?: string | null;
-  sourceKind: string;
-  sourceId: string;
-  confidence?: number;
-  contentHash?: string | null;
-  expiresAt?: number | null;
-}
-
-export interface OfflinePathDto {
-  serverId: string;
-  trackId: string;
-  localPath?: string | null;
-  missing: boolean;
-}
-
-export interface PurgeReportDto {
-  tracksDeleted: number;
-  albumsDeleted: number;
-  artistsDeleted: number;
-  offlineRowsDeleted: number;
-  bytesFreed: number;
-}
-
-export interface SyncJobDto {
-  jobId: string;
-  serverId: string;
-  kind: string; // 'initial_sync' | 'delta_sync'
-}
-
-// ── Advanced Search (PR-5d, §5.13 / §5.5B) ────────────────────────────
-
-export type LibraryEntityType = 'artist' | 'album' | 'track';
-
-/** v1 operator set the Rust `FilterFieldRegistry` accepts (§5.13.2). */
-export type FilterOperator = 'eq' | 'gte' | 'lte' | 'between' | 'fts' | 'is_true' | 'in';
-
-export type SortDir = 'asc' | 'desc';
-
-export interface LibraryFilterClause {
-  field: string; // registry id, e.g. 'genre' | 'year' | 'bpm'
-  op: FilterOperator;
-  value?: string | number | boolean | null;
-  valueTo?: number | null; // between: inclusive upper bound
-}
-
-export interface LibrarySortClause {
-  field: string;
-  dir: SortDir;
-}
-
-export interface LibraryAdvancedSearchRequest {
-  serverId: string;
-  libraryScope?: string | null;
-  query?: string | null; // shorthand → fts clause on text fields
-  entityTypes: LibraryEntityType[];
-  filters?: LibraryFilterClause[];
-  starredOnly?: boolean | null;
-  /** Server favorites ids ∩ local filters (lossless, genre, year). */
-  restrictAlbumIds?: string[] | null;
-  sort?: LibrarySortClause[];
-  limit: number;
-  offset?: number;
-  /** Skip expensive COUNT queries (Live Search). */
-  skipTotals?: boolean;
-  /** Album text query matches title/name only (All Albums scoped browse). */
-  queryAlbumTitleOnly?: boolean | null;
-}
-
-export interface LibraryAlbumDto {
-  serverId: string;
-  id: string;
-  name: string;
-  artist?: string | null;
-  artistId?: string | null;
-  songCount?: number | null;
-  durationSec?: number | null;
-  year?: number | null;
-  genre?: string | null;
-  coverArtId?: string | null;
-  starredAt?: number | null;
-  syncedAt: number;
-  rawJson: unknown;
-}
-
-export interface LibraryArtistDto {
-  serverId: string;
-  id: string;
-  name: string;
-  nameSort?: string | null;
-  albumCount?: number | null;
-  syncedAt: number;
-  rawJson: unknown;
-}
-
-export interface LibrarySearchTotals {
-  artists: number;
-  albums: number;
-  tracks: number;
-}
-
-export interface LibraryAdvancedSearchResponse {
-  artists: LibraryArtistDto[];
-  albums: LibraryAlbumDto[];
-  tracks: LibraryTrackDto[];
-  totals: LibrarySearchTotals;
-  /** Registry field ids actually applied — UI chips / debug. */
-  appliedFilters: string[];
-  source: 'local' | 'network' | 'mixed';
-}
-
-export interface LibraryCrossServerSearchResponse {
-  hits: LibraryTrackDto[];
-  /** Fuzzy `title LIKE` matches the exact FTS pass missed (§5.9 / H3). */
-  fuzzy: LibraryTrackDto[];
-  serversSearched: string[];
-}
-
-function serverIndexKeyForId(serverId: string): string {
-  const server = useAuthStore.getState().servers.find(s => s.id === serverId);
-  if (!server) return serverId;
-  return serverIndexKeyFromUrl(server.url) || serverId;
-}
-
-function mapServerIdFromIndexKey(serverId: string, fallback?: string): string {
-  if (fallback) return fallback;
-  return resolveServerIdForIndexKey(serverId);
-}
-
-function mapTracksServerId(
-  tracks: LibraryTrackDto[],
-  fallbackServerId?: string,
-): LibraryTrackDto[] {
-  if (tracks.length === 0) return tracks;
-  return tracks.map(track => ({
-    ...track,
-    serverId: mapServerIdFromIndexKey(track.serverId, fallbackServerId),
-  }));
-}
-
-// ── Read commands (PR-5a) ─────────────────────────────────────────────
-
-export function libraryGetStatus(
-  serverId: string,
-  libraryScope?: string,
-): Promise<SyncStateDto> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<SyncStateDto>('library_get_status', { serverId: indexKey, libraryScope })
-    .then(status => ({ ...status, serverId }));
-}
-
-export function librarySearch(
-  serverId: string,
-  query: string,
-  options?: { limit?: number; offset?: number; libraryScope?: string },
-): Promise<LibraryTracksEnvelope> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<LibraryTracksEnvelope>('library_search', {
-    serverId: indexKey,
-    query,
-    limit: options?.limit,
-    offset: options?.offset,
-    libraryScope: options?.libraryScope,
-  }).then(envelope => ({
-    ...envelope,
-    tracks: mapTracksServerId(envelope.tracks, serverId),
-  }));
-}
-
-/**
- * Advanced Search against the local index (§5.13). The frontend fallback
- * (PR-7 F2) decides local vs network and maps the same `LibraryFilterClause`
- * shape onto the network path; this wrapper only talks to the local builder.
- */
-export function libraryAdvancedSearch(
-  request: LibraryAdvancedSearchRequest,
-): Promise<LibraryAdvancedSearchResponse> {
-  const indexKey = serverIndexKeyForId(request.serverId);
-  return invoke<LibraryAdvancedSearchResponse>('library_advanced_search', {
-    request: { ...request, serverId: indexKey },
-  }).then(response => ({
-    ...response,
-    artists: response.artists.map(artist => ({
-      ...artist,
-      serverId: mapServerIdFromIndexKey(artist.serverId, request.serverId),
-    })),
-    albums: response.albums.map(album => ({
-      ...album,
-      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
-    })),
-    tracks: mapTracksServerId(response.tracks, request.serverId),
-  }));
-}
-
-export interface LibraryLiveSearchResponse {
-  artists: LibraryArtistDto[];
-  albums: LibraryAlbumDto[];
-  tracks: LibraryTrackDto[];
-  source: 'local' | 'network' | 'mixed';
-}
-
-/** Live Search dropdown — one lean FTS query (§5.9), not Advanced Search. */
-export interface LibraryLiveSearchRequest {
-  serverId: string;
-  query: string;
-  /** Subsonic `musicFolderId` / Navidrome library id — omit for all libraries. */
-  libraryScope?: string | null;
-  artistLimit?: number;
-  albumLimit?: number;
-  songLimit?: number;
-  /** UI generation — stale Rust FTS passes are dropped server-side. */
-  requestEpoch?: number;
-}
-
-export function libraryLiveSearch(request: LibraryLiveSearchRequest): Promise<LibraryLiveSearchResponse> {
-  const indexKey = serverIndexKeyForId(request.serverId);
-  return invoke<LibraryLiveSearchResponse>('library_live_search', {
-    request: { ...request, serverId: indexKey },
-  }).then(response => ({
-    ...response,
-    artists: response.artists.map(artist => ({
-      ...artist,
-      serverId: mapServerIdFromIndexKey(artist.serverId, request.serverId),
-    })),
-    albums: response.albums.map(album => ({
-      ...album,
-      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
-    })),
-    tracks: mapTracksServerId(response.tracks, request.serverId),
-  }));
-}
-
-export interface LibraryLosslessAlbumsRequest {
-  serverId: string;
-  libraryScope?: string | null;
-  limit?: number;
-  offset?: number;
-}
-
-export interface LibraryLosslessAlbumsResponse {
-  albums: LibraryAlbumDto[];
-  hasMore: boolean;
-  source: 'local';
-}
-
-/** Paginated lossless albums from the local track index. */
-export function libraryListLosslessAlbums(
-  request: LibraryLosslessAlbumsRequest,
-): Promise<LibraryLosslessAlbumsResponse> {
-  const indexKey = serverIndexKeyForId(request.serverId);
-  return invoke<LibraryLosslessAlbumsResponse>('library_list_lossless_albums', {
-    request: {
-      serverId: indexKey,
-      libraryScope: request.libraryScope ?? undefined,
-      limit: request.limit,
-      offset: request.offset,
-    },
-  }).then(response => ({
-    ...response,
-    albums: response.albums.map(album => ({
-      ...album,
-      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
-    })),
-  }));
-}
-
-export interface LibraryArtistLosslessBrowseRequest {
-  serverId: string;
-  artistId: string;
-  libraryScope?: string | null;
-}
-
-export interface LibraryArtistLosslessBrowseResponse {
-  albums: LibraryAlbumDto[];
-  tracks: LibraryTrackDto[];
-  source: 'local';
-}
-
-/** Lossless albums + tracks for one artist from the local index. */
-export function libraryGetArtistLosslessBrowse(
-  request: LibraryArtistLosslessBrowseRequest,
-): Promise<LibraryArtistLosslessBrowseResponse> {
-  const indexKey = serverIndexKeyForId(request.serverId);
-  return invoke<LibraryArtistLosslessBrowseResponse>('library_get_artist_lossless_browse', {
-    request: {
-      serverId: indexKey,
-      artistId: request.artistId,
-      libraryScope: request.libraryScope ?? undefined,
-    },
-  }).then(response => ({
-    ...response,
-    albums: response.albums.map(album => ({
-      ...album,
-      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
-    })),
-    tracks: mapTracksServerId(response.tracks, request.serverId),
-  }));
-}
-
-/** Cross-server FTS union over the given servers, or all `ready` ones (§5.5B). */
-export function librarySearchCrossServer(args: {
-  query: string;
-  limit?: number;
-  servers?: string[];
-}): Promise<LibraryCrossServerSearchResponse> {
-  const indexServers = args.servers?.map(serverIndexKeyForId);
-  return invoke<LibraryCrossServerSearchResponse>('library_search_cross_server', {
-    ...args,
-    servers: indexServers,
-  }).then(response => ({
-    ...response,
-    hits: mapTracksServerId(response.hits),
-    fuzzy: mapTracksServerId(response.fuzzy),
-    serversSearched: response.serversSearched.map(id => mapServerIdFromIndexKey(id)),
-  }));
-}
-
-export function libraryGetTrack(
-  serverId: string,
-  trackId: string,
-): Promise<LibraryTrackDto | null> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<LibraryTrackDto | null>('library_get_track', { serverId: indexKey, trackId })
-    .then(track => (track ? { ...track, serverId } : track));
-}
-
-/** Seed library index rows from live Subsonic song payloads (pin/download cold miss). */
-export function libraryUpsertSongsFromApi(
-  serverId: string,
-  songs: unknown[],
-): Promise<number> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<number>('library_upsert_songs_from_api', { serverId: indexKey, songs });
-}
-
-/** `library_get_tracks_batch` cap (spec §7.1). */
-export const LIBRARY_TRACKS_BATCH_LIMIT = 100;
-
-export function libraryGetTracksBatch(refs: TrackRefDto[]): Promise<LibraryTrackDto[]> {
-  const indexKeyMap = new Map<string, string>();
-  const remapped = refs.map(ref => {
-    const indexKey = serverIndexKeyForId(ref.serverId);
-    if (!indexKeyMap.has(indexKey)) indexKeyMap.set(indexKey, ref.serverId);
-    return { ...ref, serverId: indexKey };
-  });
-  return invoke<LibraryTrackDto[]>('library_get_tracks_batch', { refs: remapped })
-    .then(tracks => tracks.map(track => ({
-      ...track,
-      serverId: mapServerIdFromIndexKey(track.serverId, indexKeyMap.get(track.serverId)),
-    })));
-}
-
-/** Chunked batch fetch — safe when `refs.length` exceeds {@link LIBRARY_TRACKS_BATCH_LIMIT}. */
-export async function libraryGetTracksBatchChunked(refs: TrackRefDto[]): Promise<LibraryTrackDto[]> {
-  if (refs.length === 0) return [];
-  const out: LibraryTrackDto[] = [];
-  for (let i = 0; i < refs.length; i += LIBRARY_TRACKS_BATCH_LIMIT) {
-    const chunk = refs.slice(i, i + LIBRARY_TRACKS_BATCH_LIMIT);
-    const batch = await libraryGetTracksBatch(chunk).catch(() => []);
-    out.push(...batch);
-  }
-  return out;
-}
-
-export function libraryGetTracksByAlbum(
-  serverId: string,
-  albumId: string,
-): Promise<LibraryTrackDto[]> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<LibraryTrackDto[]>('library_get_tracks_by_album', { serverId: indexKey, albumId })
-    .then(tracks => mapTracksServerId(tracks, serverId));
-}
-
-export function libraryGetArtifact(
-  serverId: string,
-  trackId: string,
-  artifactKind: string,
-  options?: { sourceKind?: string; sourceId?: string; format?: string },
-): Promise<TrackArtifactDto | null> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<TrackArtifactDto | null>('library_get_artifact', {
-    serverId: indexKey,
-    trackId,
-    artifactKind,
-    sourceKind: options?.sourceKind,
-    sourceId: options?.sourceId,
-    format: options?.format,
-  }).then(artifact => (artifact ? { ...artifact, serverId } : artifact));
-}
-
-export function libraryGetFacts(
-  serverId: string,
-  trackId: string,
-  factKinds?: string[],
-): Promise<TrackFactDto[]> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<TrackFactDto[]>('library_get_facts', { serverId: indexKey, trackId, factKinds })
-    .then(facts => facts.map(fact => ({ ...fact, serverId })));
-}
-
-export function libraryGetOfflinePath(
-  serverId: string,
-  trackId: string,
-): Promise<OfflinePathDto> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<OfflinePathDto>('library_get_offline_path', { serverId: indexKey, trackId })
-    .then(path => ({ ...path, serverId }));
-}
-
-// ── Session + lifecycle (PR-5b) ───────────────────────────────────────
-
-export function librarySyncBindSession(args: {
-  serverId: string;
-  baseUrl: string;
-  username: string;
-  password: string;
-  libraryScope?: string;
-}): Promise<void> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<void>('library_sync_bind_session', { ...args, serverId: indexKey });
-}
-
-export function librarySyncClearSession(serverId: string): Promise<void> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<void>('library_sync_clear_session', { serverId: indexKey });
-}
-
-export type PlaybackHint = 'idle' | 'playing' | 'prefetch_active';
-
-export function libraryGetPlaybackHint(): Promise<PlaybackHint> {
-  return invoke<PlaybackHint>('library_get_playback_hint');
-}
-
-export function librarySetPlaybackHint(hint: PlaybackHint): Promise<void> {
-  return invoke<void>('library_set_playback_hint', { hint });
-}
-
-export type SyncMode = 'full' | 'delta';
-
-export function librarySyncStart(args: {
-  serverId: string;
-  mode: SyncMode;
-  libraryScope?: string;
-}): Promise<SyncJobDto> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<SyncJobDto>('library_sync_start', { ...args, serverId: indexKey })
-    .then(job => ({ ...job, serverId: args.serverId }));
-}
-
-/** Forced full-budget tombstone delta — Settings → «Verify integrity». */
-export function librarySyncVerifyIntegrity(args: {
-  serverId: string;
-  libraryScope?: string;
-}): Promise<SyncJobDto> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<SyncJobDto>('library_sync_verify_integrity', { ...args, serverId: indexKey })
-    .then(job => ({ ...job, serverId: args.serverId }));
-}
-
-export function librarySyncCancel(jobId?: string): Promise<void> {
-  return invoke<void>('library_sync_cancel', { jobId });
-}
-
-export function libraryPatchTrack(args: {
-  serverId: string;
-  trackId: string;
-  patch: {
-    starredAt?: number | null;
-    userRating?: number | null;
-    playCount?: number | null;
-    playedAt?: number | null;
-    /** E2: playback-derived `md5_16kb` content fingerprint. Normally written
-     *  by the Rust analysis bridge; exposed here for contract completeness. */
-    contentHash?: string | null;
-  };
-}): Promise<void> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<void>('library_patch_track', { ...args, serverId: indexKey });
-}
-
-/** Server favorites → `album.starred_at` (UPDATE only, no stub rows). */
-export function libraryReconcileAlbumStars(args: {
-  serverId: string;
-  starredAlbums: Array<{ id: string; starredAt: number }>;
-}): Promise<void> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<void>('library_reconcile_album_stars', {
-    serverId: indexKey,
-    starredAlbums: args.starredAlbums.map(a => ({ id: a.id, starredAt: a.starredAt })),
-  });
-}
-
-export function libraryPutArtifact(args: {
-  serverId: string;
-  trackId: string;
-  artifact: ArtifactInputDto;
-}): Promise<void> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<void>('library_put_artifact', { ...args, serverId: indexKey });
-}
-
-export function libraryPutFact(args: {
-  serverId: string;
-  trackId: string;
-  fact: FactInputDto;
-}): Promise<void> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<void>('library_put_fact', { ...args, serverId: indexKey });
-}
-
-export function libraryPurgeServer(args: {
-  serverId: string;
-  includeAnalysis?: boolean;
-  includeOffline?: boolean;
-}): Promise<PurgeReportDto> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<PurgeReportDto>('library_purge_server', { ...args, serverId: indexKey });
-}
-
-export function libraryDeleteServerData(serverId: string): Promise<void> {
-  const indexKey = serverIndexKeyForId(serverId);
-  return invoke<void>('library_delete_server_data', { serverId: indexKey });
-}
-
-// ── Player stats (local listening history) ────────────────────────────
-
-export type PlaySessionEndReason = 'ended' | 'skip' | 'stop' | 'switch' | 'close';
-
-export type PlaySessionInput = {
-  serverId: string;
-  trackId: string;
-  startedAtMs: number;
-  listenedSec: number;
-  positionMaxSec: number;
-  endReason: PlaySessionEndReason;
-  /** Player-known track duration when the library index has none. */
-  durationSecHint?: number;
-};
-
-export type PlaySessionYearSummary = {
-  totalListenedSec: number;
-  sessionCount: number;
-  trackPlayCount: number;
-  uniqueTrackCount: number;
-  listeningDayCount: number;
-  fullCount: number;
-  partialCount: number;
-};
-
-export type PlaySessionHeatmapDay = {
-  date: string;
-  trackPlayCount: number;
-};
-
-export type PlaySessionDayTrack = {
-  serverId: string;
-  trackId: string;
-  title: string;
-  artist: string | null;
-  listenedSec: number;
-  completion: 'partial' | 'full';
-  startedAtMs: number;
-};
-
-export type PlaySessionDayDetail = {
-  totals: {
-    totalListenedSec: number;
-    sessionCount: number;
-    trackPlayCount: number;
-    fullCount: number;
-    partialCount: number;
-  };
-  tracks: PlaySessionDayTrack[];
-};
-
-export type PlaySessionYearBounds = {
-  minYear: number | null;
-  maxYear: number | null;
-};
-
-export type CatalogYearBounds = {
-  minYear: number | null;
-  maxYear: number | null;
-};
-
-export type GenreAlbumCountRow = {
-  value: string;
-  albumCount: number;
-  songCount: number;
-};
-
-export function libraryGetCatalogYearBounds(args: { serverId: string }): Promise<CatalogYearBounds> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<CatalogYearBounds>('library_get_catalog_year_bounds', {
-    serverId: indexKey,
-  });
-}
-
-export function libraryGetGenreAlbumCounts(args: {
-  serverId: string;
-  libraryScope?: string;
-}): Promise<GenreAlbumCountRow[]> {
-  const indexKey = serverIndexKeyForId(args.serverId);
-  return invoke<GenreAlbumCountRow[]>('library_get_genre_album_counts', {
-    serverId: indexKey,
-    libraryScope: args.libraryScope,
-  });
-}
-
-export type LibraryGenreAlbumsRequest = {
-  serverId: string;
-  genre: string;
-  libraryScope?: string | null;
-  sort?: LibrarySortClause[];
-  limit?: number;
-  offset?: number;
-  includeTotal?: boolean;
-};
-
-export type LibraryGenreAlbumsResponse = {
-  albums: LibraryAlbumDto[];
-  hasMore: boolean;
-  total?: number | null;
-  source: 'local';
-};
-
-/** Paginated albums for one genre from the local track index. */
-export function libraryListAlbumsByGenre(
-  request: LibraryGenreAlbumsRequest,
-): Promise<LibraryGenreAlbumsResponse> {
-  const indexKey = serverIndexKeyForId(request.serverId);
-  return invoke<LibraryGenreAlbumsResponse>('library_list_albums_by_genre', {
-    request: {
-      serverId: indexKey,
-      genre: request.genre,
-      libraryScope: request.libraryScope ?? undefined,
-      sort: request.sort ?? [],
-      limit: request.limit ?? 50,
-      offset: request.offset ?? 0,
-      includeTotal: request.includeTotal ?? false,
-    },
-  }).then(response => ({
-    ...response,
-    albums: response.albums.map(album => ({
-      ...album,
-      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
-    })),
-  }));
-}
-
-export type PlaySessionRecentDay = {
-  date: string;
-  totalListenedSec: number;
-  sessionCount: number;
-  trackPlayCount: number;
-  fullCount: number;
-  partialCount: number;
-};
-
-export function libraryRecordPlaySession(input: PlaySessionInput): Promise<void> {
-  const indexKey = serverIndexKeyForId(input.serverId);
-  return invoke<void>('library_record_play_session', { input: { ...input, serverId: indexKey } });
-}
-
-export function libraryGetPlayerStatsYearSummary(year: number): Promise<PlaySessionYearSummary> {
-  return invoke<PlaySessionYearSummary>('library_get_player_stats_year_summary', { year });
-}
-
-export function libraryGetPlayerStatsHeatmap(year: number): Promise<PlaySessionHeatmapDay[]> {
-  return invoke<PlaySessionHeatmapDay[]>('library_get_player_stats_heatmap', { year });
-}
-
-export function libraryGetPlayerStatsDayDetail(dateIso: string): Promise<PlaySessionDayDetail> {
-  return invoke<PlaySessionDayDetail>('library_get_player_stats_day_detail', { dateIso })
-    .then(detail => ({
-      ...detail,
-      tracks: detail.tracks.map(track => ({
-        ...track,
-        serverId: mapServerIdFromIndexKey(track.serverId),
-      })),
-    }));
-}
-
-export function libraryGetPlayerStatsYearBounds(): Promise<PlaySessionYearBounds> {
-  return invoke<PlaySessionYearBounds>('library_get_player_stats_year_bounds');
-}
-
-export function libraryGetPlayerStatsRecentDays(limit = 30): Promise<PlaySessionRecentDay[]> {
-  return invoke<PlaySessionRecentDay[]>('library_get_player_stats_recent_days', { limit });
-}
-
-export type PlaySessionRecentTrack = {
-  serverId: string;
-  trackId: string;
-  title: string;
-  artist: string | null;
-  album: string | null;
-  albumId: string | null;
-  coverArtId: string | null;
-  startedAtMs: number;
-  listenedSec: number;
-  completion: 'partial' | 'full';
-};
-
-export function libraryGetRecentPlaySessions(args?: {
-  limit?: number;
-  sinceMs?: number;
-}): Promise<PlaySessionRecentTrack[]> {
-  return invoke<PlaySessionRecentTrack[]>('library_get_recent_play_sessions', {
-    limit: args?.limit,
-    sinceMs: args?.sinceMs,
-  }).then(rows =>
-    rows.map(row => ({
-      ...row,
-      serverId: mapServerIdFromIndexKey(row.serverId),
-    })),
-  );
-}
-
-// ── Event subscriptions ───────────────────────────────────────────────
-
-export interface LibrarySyncProgressPayload {
-  serverId: string;
-  libraryScope: string;
-  /** 'phase_changed' | 'ingest_page' | 'remapped' | 'tombstoned' | 'completed' | 'error' */
-  kind: string;
-  phase?: string | null;
-  ingestedTotal?: number | null;
-  batchCount?: number | null;
-  remappedCount?: number | null;
-  tombstonesChecked?: number | null;
-  tombstonesDeleted?: number | null;
-  completedKind?: string | null;
-  message?: string | null;
-  /** S1 per-batch timings from the Rust ingest runner (when available). */
-  ingestMetrics?: IngestBatchMetrics | null;
-}
-
-export interface IngestBatchMetrics {
-  offset: number;
-  strategy: string;
-  fetchMs: number;
-  writeMs: number;
-  lockWaitMs: number;
-  sqlExecMs: number;
-  persistMs: number;
-  rowCount: number;
-  bulkIngestActive: boolean;
-}
-
-export interface LibrarySyncIdlePayload {
-  serverId: string;
-  libraryScope: string;
-  kind: string; // 'initial_sync' | 'delta_sync'
-  ok: boolean;
-  error?: string | null;
-}
-
-export function subscribeLibrarySyncProgress(
-  handler: (payload: LibrarySyncProgressPayload) => void,
-): Promise<UnlistenFn> {
-  return listen<LibrarySyncProgressPayload>('library:sync-progress', ({ payload }) =>
-    handler(payload),
-  );
-}
-
-export function subscribeLibrarySyncIdle(
-  handler: (payload: LibrarySyncIdlePayload) => void,
-): Promise<UnlistenFn> {
-  return listen<LibrarySyncIdlePayload>('library:sync-idle', ({ payload }) =>
-    handler(payload),
-  );
-}
-
-// ── Genre tags startup backfill (multi-genre local index) ───────────────
-
-export interface GenreTagsInspectDto {
-  needed: boolean;
-  totalTracks: number;
-  doneTracks: number;
-}
-
-export interface GenreTagsProgressEvent {
-  done: number;
-  total: number;
-}
-
-export function libraryGenreTagsInspect(): Promise<GenreTagsInspectDto> {
-  return invoke<GenreTagsInspectDto>('library_genre_tags_inspect');
-}
-
-export function libraryGenreTagsRun(): Promise<void> {
-  return invoke<void>('library_genre_tags_run');
-}
+export * from './library/dto';
+export * from './library/reads';
+export * from './library/sync';
+export * from './library/stats';
+export * from './library/events';
diff --git a/src/lib/api/library/dto.ts b/src/lib/api/library/dto.ts
new file mode 100644
index 00000000..44c88788
--- /dev/null
+++ b/src/lib/api/library/dto.ts
@@ -0,0 +1,466 @@
+/**
+ * DTO mirrors for the `library_*` Tauri command surface (camelCase, matching the
+ * Rust `#[serde(rename_all = "camelCase")]`). Split out of the former single
+ * `lib/api/library.ts` god-module; the wrappers (reads/sync/stats/events) and the
+ * `@/lib/api/library` barrel re-export these, so consumers are unchanged.
+ */
+
+export interface TrackRefDto {
+  serverId: string;
+  trackId: string;
+  contentHash?: string | null;
+}
+
+/** E3 readiness summary — present only on single-track `libraryGetTrack` reads. */
+export interface TrackEnrichmentDto {
+  waveformReady: boolean;
+  loudnessReady: boolean;
+  lyricsCached: boolean;
+}
+
+export interface LibraryTrackDto {
+  serverId: string;
+  id: string;
+  contentHash?: string | null;
+  title: string;
+  titleSort?: string | null;
+  artist?: string | null;
+  artistId?: string | null;
+  album: string;
+  albumId?: string | null;
+  albumArtist?: string | null;
+  durationSec: number;
+  trackNumber?: number | null;
+  discNumber?: number | null;
+  year?: number | null;
+  genre?: string | null;
+  suffix?: string | null;
+  bitRate?: number | null;
+  sizeBytes?: number | null;
+  coverArtId?: string | null;
+  starredAt?: number | null;
+  userRating?: number | null;
+  playCount?: number | null;
+  playedAt?: number | null;
+  serverPath?: string | null;
+  libraryId?: string | null;
+  isrc?: string | null;
+  mbidRecording?: string | null;
+  bpm?: number | null;
+  /** `'analysis'` | `'tag'` — Advanced Search BPM dual-storage projection only. */
+  bpmSource?: string | null;
+  replayGainTrackDb?: number | null;
+  replayGainAlbumDb?: number | null;
+  serverUpdatedAt?: number | null;
+  serverCreatedAt?: number | null;
+  syncedAt: number;
+  /** E3: populated only by `libraryGetTrack` (omitted on list/batch reads). */
+  enrichment?: TrackEnrichmentDto | null;
+  rawJson: unknown;
+}
+
+export interface SyncStateDto {
+  serverId: string;
+  libraryScope: string;
+  syncPhase: string;
+  capabilityFlags: number;
+  libraryTier: string;
+  lastFullSyncAt?: number | null;
+  lastDeltaSyncAt?: number | null;
+  nextPollAt?: number | null;
+  serverLastScanIso?: string | null;
+  indexesLastModifiedMs?: number | null;
+  artistsLastModifiedMs?: number | null;
+  ignoredArticles?: string | null;
+  localTrackCount?: number | null;
+  serverTrackCount?: number | null;
+  lastError?: string | null;
+  localTracksMaxUpdatedMs?: number | null;
+  /** True when at least one non-deleted track exists locally (cheap EXISTS). */
+  hasLocalTracks?: boolean;
+  ingestStrategy?: string | null;
+  ingestPhase?: string | null;
+  /** Tracks ingested per persisted initial-sync cursor (IS-3 progress). */
+  cursorIngestedCount?: number | null;
+  n1BulkUnreliable?: boolean | null;
+}
+
+export interface LibraryTracksEnvelope {
+  tracks: LibraryTrackDto[];
+  total: number;
+}
+
+export interface TrackArtifactDto {
+  serverId: string;
+  trackId: string;
+  artifactKind: string;
+  format: string;
+  sourceKind: string;
+  sourceId: string;
+  language?: string | null;
+  contentText?: string | null;
+  contentBytes: number;
+  notFound: boolean;
+  contentHash?: string | null;
+  fetchedAt: number;
+  expiresAt?: number | null;
+}
+
+export interface ArtifactInputDto {
+  artifactKind: string;
+  format: string;
+  sourceKind: string;
+  sourceId: string;
+  language?: string | null;
+  contentText?: string | null;
+  contentBlob?: number[] | null;
+  contentBytes?: number;
+  notFound?: boolean;
+  contentHash?: string | null;
+  expiresAt?: number | null;
+}
+
+export interface TrackFactDto {
+  serverId: string;
+  trackId: string;
+  factKind: string;
+  valueReal?: number | null;
+  valueInt?: number | null;
+  valueText?: string | null;
+  unit?: string | null;
+  sourceKind: string;
+  sourceId: string;
+  confidence: number;
+  contentHash?: string | null;
+  fetchedAt: number;
+  expiresAt?: number | null;
+}
+
+export interface FactInputDto {
+  factKind: string;
+  valueReal?: number | null;
+  valueInt?: number | null;
+  valueText?: string | null;
+  unit?: string | null;
+  sourceKind: string;
+  sourceId: string;
+  confidence?: number;
+  contentHash?: string | null;
+  expiresAt?: number | null;
+}
+
+export interface OfflinePathDto {
+  serverId: string;
+  trackId: string;
+  localPath?: string | null;
+  missing: boolean;
+}
+
+export interface PurgeReportDto {
+  tracksDeleted: number;
+  albumsDeleted: number;
+  artistsDeleted: number;
+  offlineRowsDeleted: number;
+  bytesFreed: number;
+}
+
+export interface SyncJobDto {
+  jobId: string;
+  serverId: string;
+  kind: string; // 'initial_sync' | 'delta_sync'
+}
+
+// ── Advanced Search (PR-5d, §5.13 / §5.5B) ────────────────────────────
+
+export type LibraryEntityType = 'artist' | 'album' | 'track';
+
+/** v1 operator set the Rust `FilterFieldRegistry` accepts (§5.13.2). */
+export type FilterOperator = 'eq' | 'gte' | 'lte' | 'between' | 'fts' | 'is_true' | 'in';
+
+export type SortDir = 'asc' | 'desc';
+
+export interface LibraryFilterClause {
+  field: string; // registry id, e.g. 'genre' | 'year' | 'bpm'
+  op: FilterOperator;
+  value?: string | number | boolean | null;
+  valueTo?: number | null; // between: inclusive upper bound
+}
+
+export interface LibrarySortClause {
+  field: string;
+  dir: SortDir;
+}
+
+export interface LibraryAdvancedSearchRequest {
+  serverId: string;
+  libraryScope?: string | null;
+  query?: string | null; // shorthand → fts clause on text fields
+  entityTypes: LibraryEntityType[];
+  filters?: LibraryFilterClause[];
+  starredOnly?: boolean | null;
+  /** Server favorites ids ∩ local filters (lossless, genre, year). */
+  restrictAlbumIds?: string[] | null;
+  sort?: LibrarySortClause[];
+  limit: number;
+  offset?: number;
+  /** Skip expensive COUNT queries (Live Search). */
+  skipTotals?: boolean;
+  /** Album text query matches title/name only (All Albums scoped browse). */
+  queryAlbumTitleOnly?: boolean | null;
+}
+
+export interface LibraryAlbumDto {
+  serverId: string;
+  id: string;
+  name: string;
+  artist?: string | null;
+  artistId?: string | null;
+  songCount?: number | null;
+  durationSec?: number | null;
+  year?: number | null;
+  genre?: string | null;
+  coverArtId?: string | null;
+  starredAt?: number | null;
+  syncedAt: number;
+  rawJson: unknown;
+}
+
+export interface LibraryArtistDto {
+  serverId: string;
+  id: string;
+  name: string;
+  nameSort?: string | null;
+  albumCount?: number | null;
+  syncedAt: number;
+  rawJson: unknown;
+}
+
+export interface LibrarySearchTotals {
+  artists: number;
+  albums: number;
+  tracks: number;
+}
+
+export interface LibraryAdvancedSearchResponse {
+  artists: LibraryArtistDto[];
+  albums: LibraryAlbumDto[];
+  tracks: LibraryTrackDto[];
+  totals: LibrarySearchTotals;
+  /** Registry field ids actually applied — UI chips / debug. */
+  appliedFilters: string[];
+  source: 'local' | 'network' | 'mixed';
+}
+
+export interface LibraryCrossServerSearchResponse {
+  hits: LibraryTrackDto[];
+  /** Fuzzy `title LIKE` matches the exact FTS pass missed (§5.9 / H3). */
+  fuzzy: LibraryTrackDto[];
+  serversSearched: string[];
+}
+
+export interface LibraryLiveSearchResponse {
+  artists: LibraryArtistDto[];
+  albums: LibraryAlbumDto[];
+  tracks: LibraryTrackDto[];
+  source: 'local' | 'network' | 'mixed';
+}
+
+/** Live Search dropdown — one lean FTS query (§5.9), not Advanced Search. */
+export interface LibraryLiveSearchRequest {
+  serverId: string;
+  query: string;
+  /** Subsonic `musicFolderId` / Navidrome library id — omit for all libraries. */
+  libraryScope?: string | null;
+  artistLimit?: number;
+  albumLimit?: number;
+  songLimit?: number;
+  /** UI generation — stale Rust FTS passes are dropped server-side. */
+  requestEpoch?: number;
+}
+
+export interface LibraryLosslessAlbumsRequest {
+  serverId: string;
+  libraryScope?: string | null;
+  limit?: number;
+  offset?: number;
+}
+
+export interface LibraryLosslessAlbumsResponse {
+  albums: LibraryAlbumDto[];
+  hasMore: boolean;
+  source: 'local';
+}
+
+export interface LibraryArtistLosslessBrowseRequest {
+  serverId: string;
+  artistId: string;
+  libraryScope?: string | null;
+}
+
+export interface LibraryArtistLosslessBrowseResponse {
+  albums: LibraryAlbumDto[];
+  tracks: LibraryTrackDto[];
+  source: 'local';
+}
+
+export type PlaybackHint = 'idle' | 'playing' | 'prefetch_active';
+
+export type SyncMode = 'full' | 'delta';
+
+// ── Player stats (local listening history) ────────────────────────────
+
+export type PlaySessionEndReason = 'ended' | 'skip' | 'stop' | 'switch' | 'close';
+
+export type PlaySessionInput = {
+  serverId: string;
+  trackId: string;
+  startedAtMs: number;
+  listenedSec: number;
+  positionMaxSec: number;
+  endReason: PlaySessionEndReason;
+  /** Player-known track duration when the library index has none. */
+  durationSecHint?: number;
+};
+
+export type PlaySessionYearSummary = {
+  totalListenedSec: number;
+  sessionCount: number;
+  trackPlayCount: number;
+  uniqueTrackCount: number;
+  listeningDayCount: number;
+  fullCount: number;
+  partialCount: number;
+};
+
+export type PlaySessionHeatmapDay = {
+  date: string;
+  trackPlayCount: number;
+};
+
+export type PlaySessionDayTrack = {
+  serverId: string;
+  trackId: string;
+  title: string;
+  artist: string | null;
+  listenedSec: number;
+  completion: 'partial' | 'full';
+  startedAtMs: number;
+};
+
+export type PlaySessionDayDetail = {
+  totals: {
+    totalListenedSec: number;
+    sessionCount: number;
+    trackPlayCount: number;
+    fullCount: number;
+    partialCount: number;
+  };
+  tracks: PlaySessionDayTrack[];
+};
+
+export type PlaySessionYearBounds = {
+  minYear: number | null;
+  maxYear: number | null;
+};
+
+export type CatalogYearBounds = {
+  minYear: number | null;
+  maxYear: number | null;
+};
+
+export type GenreAlbumCountRow = {
+  value: string;
+  albumCount: number;
+  songCount: number;
+};
+
+export type LibraryGenreAlbumsRequest = {
+  serverId: string;
+  genre: string;
+  libraryScope?: string | null;
+  sort?: LibrarySortClause[];
+  limit?: number;
+  offset?: number;
+  includeTotal?: boolean;
+};
+
+export type LibraryGenreAlbumsResponse = {
+  albums: LibraryAlbumDto[];
+  hasMore: boolean;
+  total?: number | null;
+  source: 'local';
+};
+
+export type PlaySessionRecentDay = {
+  date: string;
+  totalListenedSec: number;
+  sessionCount: number;
+  trackPlayCount: number;
+  fullCount: number;
+  partialCount: number;
+};
+
+export type PlaySessionRecentTrack = {
+  serverId: string;
+  trackId: string;
+  title: string;
+  artist: string | null;
+  album: string | null;
+  albumId: string | null;
+  coverArtId: string | null;
+  startedAtMs: number;
+  listenedSec: number;
+  completion: 'partial' | 'full';
+};
+
+// ── Event subscriptions ───────────────────────────────────────────────
+
+export interface LibrarySyncProgressPayload {
+  serverId: string;
+  libraryScope: string;
+  /** 'phase_changed' | 'ingest_page' | 'remapped' | 'tombstoned' | 'completed' | 'error' */
+  kind: string;
+  phase?: string | null;
+  ingestedTotal?: number | null;
+  batchCount?: number | null;
+  remappedCount?: number | null;
+  tombstonesChecked?: number | null;
+  tombstonesDeleted?: number | null;
+  completedKind?: string | null;
+  message?: string | null;
+  /** S1 per-batch timings from the Rust ingest runner (when available). */
+  ingestMetrics?: IngestBatchMetrics | null;
+}
+
+export interface IngestBatchMetrics {
+  offset: number;
+  strategy: string;
+  fetchMs: number;
+  writeMs: number;
+  lockWaitMs: number;
+  sqlExecMs: number;
+  persistMs: number;
+  rowCount: number;
+  bulkIngestActive: boolean;
+}
+
+export interface LibrarySyncIdlePayload {
+  serverId: string;
+  libraryScope: string;
+  kind: string; // 'initial_sync' | 'delta_sync'
+  ok: boolean;
+  error?: string | null;
+}
+
+// ── Genre tags startup backfill (multi-genre local index) ───────────────
+
+export interface GenreTagsInspectDto {
+  needed: boolean;
+  totalTracks: number;
+  doneTracks: number;
+}
+
+export interface GenreTagsProgressEvent {
+  done: number;
+  total: number;
+}
diff --git a/src/lib/api/library/events.ts b/src/lib/api/library/events.ts
new file mode 100644
index 00000000..4adc43e8
--- /dev/null
+++ b/src/lib/api/library/events.ts
@@ -0,0 +1,36 @@
+/**
+ * Event subscriptions (`library:sync-progress` / `library:sync-idle`, §7.2) plus
+ * the genre-tags startup backfill commands. Split out of the former single
+ * `lib/api/library.ts`; re-exported via the `@/lib/api/library` barrel.
+ */
+import { invoke } from '@tauri-apps/api/core';
+import { listen, type UnlistenFn } from '@tauri-apps/api/event';
+import type {
+  LibrarySyncProgressPayload,
+  LibrarySyncIdlePayload,
+  GenreTagsInspectDto,
+} from './dto';
+
+export function subscribeLibrarySyncProgress(
+  handler: (payload: LibrarySyncProgressPayload) => void,
+): Promise<UnlistenFn> {
+  return listen<LibrarySyncProgressPayload>('library:sync-progress', ({ payload }) =>
+    handler(payload),
+  );
+}
+
+export function subscribeLibrarySyncIdle(
+  handler: (payload: LibrarySyncIdlePayload) => void,
+): Promise<UnlistenFn> {
+  return listen<LibrarySyncIdlePayload>('library:sync-idle', ({ payload }) =>
+    handler(payload),
+  );
+}
+
+export function libraryGenreTagsInspect(): Promise<GenreTagsInspectDto> {
+  return invoke<GenreTagsInspectDto>('library_genre_tags_inspect');
+}
+
+export function libraryGenreTagsRun(): Promise<void> {
+  return invoke<void>('library_genre_tags_run');
+}
diff --git a/src/lib/api/library/internal.ts b/src/lib/api/library/internal.ts
new file mode 100644
index 00000000..1f7ca19f
--- /dev/null
+++ b/src/lib/api/library/internal.ts
@@ -0,0 +1,30 @@
+/**
+ * Internal server-id ↔ index-key mapping helpers shared by the library command
+ * wrappers (reads/sync/stats). Not part of the public `@/lib/api/library` barrel.
+ */
+import { useAuthStore } from '@/store/authStore';
+import { serverIndexKeyFromUrl } from '@/lib/server/serverIndexKey';
+import { resolveServerIdForIndexKey } from '@/lib/server/serverLookup';
+import type { LibraryTrackDto } from './dto';
+
+export function serverIndexKeyForId(serverId: string): string {
+  const server = useAuthStore.getState().servers.find(s => s.id === serverId);
+  if (!server) return serverId;
+  return serverIndexKeyFromUrl(server.url) || serverId;
+}
+
+export function mapServerIdFromIndexKey(serverId: string, fallback?: string): string {
+  if (fallback) return fallback;
+  return resolveServerIdForIndexKey(serverId);
+}
+
+export function mapTracksServerId(
+  tracks: LibraryTrackDto[],
+  fallbackServerId?: string,
+): LibraryTrackDto[] {
+  if (tracks.length === 0) return tracks;
+  return tracks.map(track => ({
+    ...track,
+    serverId: mapServerIdFromIndexKey(track.serverId, fallbackServerId),
+  }));
+}
diff --git a/src/lib/api/library/reads.ts b/src/lib/api/library/reads.ts
new file mode 100644
index 00000000..f5e8eeb0
--- /dev/null
+++ b/src/lib/api/library/reads.ts
@@ -0,0 +1,247 @@
+/**
+ * Read commands (PR-5a) — typed wrappers around the `library_*` read/query Tauri
+ * commands. Split out of the former single `lib/api/library.ts`; re-exported via
+ * the `@/lib/api/library` barrel.
+ */
+import { invoke } from '@tauri-apps/api/core';
+import { serverIndexKeyForId, mapServerIdFromIndexKey, mapTracksServerId } from './internal';
+import type {
+  SyncStateDto,
+  LibraryTracksEnvelope,
+  LibraryAdvancedSearchRequest,
+  LibraryAdvancedSearchResponse,
+  LibraryLiveSearchRequest,
+  LibraryLiveSearchResponse,
+  LibraryLosslessAlbumsRequest,
+  LibraryLosslessAlbumsResponse,
+  LibraryArtistLosslessBrowseRequest,
+  LibraryArtistLosslessBrowseResponse,
+  LibraryCrossServerSearchResponse,
+  LibraryTrackDto,
+  TrackRefDto,
+  TrackArtifactDto,
+  TrackFactDto,
+  OfflinePathDto,
+} from './dto';
+
+export function libraryGetStatus(
+  serverId: string,
+  libraryScope?: string,
+): Promise<SyncStateDto> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<SyncStateDto>('library_get_status', { serverId: indexKey, libraryScope })
+    .then(status => ({ ...status, serverId }));
+}
+
+export function librarySearch(
+  serverId: string,
+  query: string,
+  options?: { limit?: number; offset?: number; libraryScope?: string },
+): Promise<LibraryTracksEnvelope> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<LibraryTracksEnvelope>('library_search', {
+    serverId: indexKey,
+    query,
+    limit: options?.limit,
+    offset: options?.offset,
+    libraryScope: options?.libraryScope,
+  }).then(envelope => ({
+    ...envelope,
+    tracks: mapTracksServerId(envelope.tracks, serverId),
+  }));
+}
+
+/**
+ * Advanced Search against the local index (§5.13). The frontend fallback
+ * (PR-7 F2) decides local vs network and maps the same `LibraryFilterClause`
+ * shape onto the network path; this wrapper only talks to the local builder.
+ */
+export function libraryAdvancedSearch(
+  request: LibraryAdvancedSearchRequest,
+): Promise<LibraryAdvancedSearchResponse> {
+  const indexKey = serverIndexKeyForId(request.serverId);
+  return invoke<LibraryAdvancedSearchResponse>('library_advanced_search', {
+    request: { ...request, serverId: indexKey },
+  }).then(response => ({
+    ...response,
+    artists: response.artists.map(artist => ({
+      ...artist,
+      serverId: mapServerIdFromIndexKey(artist.serverId, request.serverId),
+    })),
+    albums: response.albums.map(album => ({
+      ...album,
+      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
+    })),
+    tracks: mapTracksServerId(response.tracks, request.serverId),
+  }));
+}
+
+export function libraryLiveSearch(request: LibraryLiveSearchRequest): Promise<LibraryLiveSearchResponse> {
+  const indexKey = serverIndexKeyForId(request.serverId);
+  return invoke<LibraryLiveSearchResponse>('library_live_search', {
+    request: { ...request, serverId: indexKey },
+  }).then(response => ({
+    ...response,
+    artists: response.artists.map(artist => ({
+      ...artist,
+      serverId: mapServerIdFromIndexKey(artist.serverId, request.serverId),
+    })),
+    albums: response.albums.map(album => ({
+      ...album,
+      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
+    })),
+    tracks: mapTracksServerId(response.tracks, request.serverId),
+  }));
+}
+
+/** Paginated lossless albums from the local track index. */
+export function libraryListLosslessAlbums(
+  request: LibraryLosslessAlbumsRequest,
+): Promise<LibraryLosslessAlbumsResponse> {
+  const indexKey = serverIndexKeyForId(request.serverId);
+  return invoke<LibraryLosslessAlbumsResponse>('library_list_lossless_albums', {
+    request: {
+      serverId: indexKey,
+      libraryScope: request.libraryScope ?? undefined,
+      limit: request.limit,
+      offset: request.offset,
+    },
+  }).then(response => ({
+    ...response,
+    albums: response.albums.map(album => ({
+      ...album,
+      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
+    })),
+  }));
+}
+
+/** Lossless albums + tracks for one artist from the local index. */
+export function libraryGetArtistLosslessBrowse(
+  request: LibraryArtistLosslessBrowseRequest,
+): Promise<LibraryArtistLosslessBrowseResponse> {
+  const indexKey = serverIndexKeyForId(request.serverId);
+  return invoke<LibraryArtistLosslessBrowseResponse>('library_get_artist_lossless_browse', {
+    request: {
+      serverId: indexKey,
+      artistId: request.artistId,
+      libraryScope: request.libraryScope ?? undefined,
+    },
+  }).then(response => ({
+    ...response,
+    albums: response.albums.map(album => ({
+      ...album,
+      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
+    })),
+    tracks: mapTracksServerId(response.tracks, request.serverId),
+  }));
+}
+
+/** Cross-server FTS union over the given servers, or all `ready` ones (§5.5B). */
+export function librarySearchCrossServer(args: {
+  query: string;
+  limit?: number;
+  servers?: string[];
+}): Promise<LibraryCrossServerSearchResponse> {
+  const indexServers = args.servers?.map(serverIndexKeyForId);
+  return invoke<LibraryCrossServerSearchResponse>('library_search_cross_server', {
+    ...args,
+    servers: indexServers,
+  }).then(response => ({
+    ...response,
+    hits: mapTracksServerId(response.hits),
+    fuzzy: mapTracksServerId(response.fuzzy),
+    serversSearched: response.serversSearched.map(id => mapServerIdFromIndexKey(id)),
+  }));
+}
+
+export function libraryGetTrack(
+  serverId: string,
+  trackId: string,
+): Promise<LibraryTrackDto | null> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<LibraryTrackDto | null>('library_get_track', { serverId: indexKey, trackId })
+    .then(track => (track ? { ...track, serverId } : track));
+}
+
+/** Seed library index rows from live Subsonic song payloads (pin/download cold miss). */
+export function libraryUpsertSongsFromApi(
+  serverId: string,
+  songs: unknown[],
+): Promise<number> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<number>('library_upsert_songs_from_api', { serverId: indexKey, songs });
+}
+
+/** `library_get_tracks_batch` cap (spec §7.1). */
+export const LIBRARY_TRACKS_BATCH_LIMIT = 100;
+
+export function libraryGetTracksBatch(refs: TrackRefDto[]): Promise<LibraryTrackDto[]> {
+  const indexKeyMap = new Map<string, string>();
+  const remapped = refs.map(ref => {
+    const indexKey = serverIndexKeyForId(ref.serverId);
+    if (!indexKeyMap.has(indexKey)) indexKeyMap.set(indexKey, ref.serverId);
+    return { ...ref, serverId: indexKey };
+  });
+  return invoke<LibraryTrackDto[]>('library_get_tracks_batch', { refs: remapped })
+    .then(tracks => tracks.map(track => ({
+      ...track,
+      serverId: mapServerIdFromIndexKey(track.serverId, indexKeyMap.get(track.serverId)),
+    })));
+}
+
+/** Chunked batch fetch — safe when `refs.length` exceeds {@link LIBRARY_TRACKS_BATCH_LIMIT}. */
+export async function libraryGetTracksBatchChunked(refs: TrackRefDto[]): Promise<LibraryTrackDto[]> {
+  if (refs.length === 0) return [];
+  const out: LibraryTrackDto[] = [];
+  for (let i = 0; i < refs.length; i += LIBRARY_TRACKS_BATCH_LIMIT) {
+    const chunk = refs.slice(i, i + LIBRARY_TRACKS_BATCH_LIMIT);
+    const batch = await libraryGetTracksBatch(chunk).catch(() => []);
+    out.push(...batch);
+  }
+  return out;
+}
+
+export function libraryGetTracksByAlbum(
+  serverId: string,
+  albumId: string,
+): Promise<LibraryTrackDto[]> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<LibraryTrackDto[]>('library_get_tracks_by_album', { serverId: indexKey, albumId })
+    .then(tracks => mapTracksServerId(tracks, serverId));
+}
+
+export function libraryGetArtifact(
+  serverId: string,
+  trackId: string,
+  artifactKind: string,
+  options?: { sourceKind?: string; sourceId?: string; format?: string },
+): Promise<TrackArtifactDto | null> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<TrackArtifactDto | null>('library_get_artifact', {
+    serverId: indexKey,
+    trackId,
+    artifactKind,
+    sourceKind: options?.sourceKind,
+    sourceId: options?.sourceId,
+    format: options?.format,
+  }).then(artifact => (artifact ? { ...artifact, serverId } : artifact));
+}
+
+export function libraryGetFacts(
+  serverId: string,
+  trackId: string,
+  factKinds?: string[],
+): Promise<TrackFactDto[]> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<TrackFactDto[]>('library_get_facts', { serverId: indexKey, trackId, factKinds })
+    .then(facts => facts.map(fact => ({ ...fact, serverId })));
+}
+
+export function libraryGetOfflinePath(
+  serverId: string,
+  trackId: string,
+): Promise<OfflinePathDto> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<OfflinePathDto>('library_get_offline_path', { serverId: indexKey, trackId })
+    .then(path => ({ ...path, serverId }));
+}
diff --git a/src/lib/api/library/stats.ts b/src/lib/api/library/stats.ts
new file mode 100644
index 00000000..c6d43355
--- /dev/null
+++ b/src/lib/api/library/stats.ts
@@ -0,0 +1,109 @@
+/**
+ * Player stats (local listening history) + genre/catalog aggregate reads. Split
+ * out of the former single `lib/api/library.ts`; re-exported via the
+ * `@/lib/api/library` barrel.
+ */
+import { invoke } from '@tauri-apps/api/core';
+import { serverIndexKeyForId, mapServerIdFromIndexKey } from './internal';
+import type {
+  CatalogYearBounds,
+  GenreAlbumCountRow,
+  LibraryGenreAlbumsRequest,
+  LibraryGenreAlbumsResponse,
+  PlaySessionInput,
+  PlaySessionYearSummary,
+  PlaySessionHeatmapDay,
+  PlaySessionDayDetail,
+  PlaySessionYearBounds,
+  PlaySessionRecentDay,
+  PlaySessionRecentTrack,
+} from './dto';
+
+export function libraryGetCatalogYearBounds(args: { serverId: string }): Promise<CatalogYearBounds> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<CatalogYearBounds>('library_get_catalog_year_bounds', {
+    serverId: indexKey,
+  });
+}
+
+export function libraryGetGenreAlbumCounts(args: {
+  serverId: string;
+  libraryScope?: string;
+}): Promise<GenreAlbumCountRow[]> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<GenreAlbumCountRow[]>('library_get_genre_album_counts', {
+    serverId: indexKey,
+    libraryScope: args.libraryScope,
+  });
+}
+
+/** Paginated albums for one genre from the local track index. */
+export function libraryListAlbumsByGenre(
+  request: LibraryGenreAlbumsRequest,
+): Promise<LibraryGenreAlbumsResponse> {
+  const indexKey = serverIndexKeyForId(request.serverId);
+  return invoke<LibraryGenreAlbumsResponse>('library_list_albums_by_genre', {
+    request: {
+      serverId: indexKey,
+      genre: request.genre,
+      libraryScope: request.libraryScope ?? undefined,
+      sort: request.sort ?? [],
+      limit: request.limit ?? 50,
+      offset: request.offset ?? 0,
+      includeTotal: request.includeTotal ?? false,
+    },
+  }).then(response => ({
+    ...response,
+    albums: response.albums.map(album => ({
+      ...album,
+      serverId: mapServerIdFromIndexKey(album.serverId, request.serverId),
+    })),
+  }));
+}
+
+export function libraryRecordPlaySession(input: PlaySessionInput): Promise<void> {
+  const indexKey = serverIndexKeyForId(input.serverId);
+  return invoke<void>('library_record_play_session', { input: { ...input, serverId: indexKey } });
+}
+
+export function libraryGetPlayerStatsYearSummary(year: number): Promise<PlaySessionYearSummary> {
+  return invoke<PlaySessionYearSummary>('library_get_player_stats_year_summary', { year });
+}
+
+export function libraryGetPlayerStatsHeatmap(year: number): Promise<PlaySessionHeatmapDay[]> {
+  return invoke<PlaySessionHeatmapDay[]>('library_get_player_stats_heatmap', { year });
+}
+
+export function libraryGetPlayerStatsDayDetail(dateIso: string): Promise<PlaySessionDayDetail> {
+  return invoke<PlaySessionDayDetail>('library_get_player_stats_day_detail', { dateIso })
+    .then(detail => ({
+      ...detail,
+      tracks: detail.tracks.map(track => ({
+        ...track,
+        serverId: mapServerIdFromIndexKey(track.serverId),
+      })),
+    }));
+}
+
+export function libraryGetPlayerStatsYearBounds(): Promise<PlaySessionYearBounds> {
+  return invoke<PlaySessionYearBounds>('library_get_player_stats_year_bounds');
+}
+
+export function libraryGetPlayerStatsRecentDays(limit = 30): Promise<PlaySessionRecentDay[]> {
+  return invoke<PlaySessionRecentDay[]>('library_get_player_stats_recent_days', { limit });
+}
+
+export function libraryGetRecentPlaySessions(args?: {
+  limit?: number;
+  sinceMs?: number;
+}): Promise<PlaySessionRecentTrack[]> {
+  return invoke<PlaySessionRecentTrack[]>('library_get_recent_play_sessions', {
+    limit: args?.limit,
+    sinceMs: args?.sinceMs,
+  }).then(rows =>
+    rows.map(row => ({
+      ...row,
+      serverId: mapServerIdFromIndexKey(row.serverId),
+    })),
+  );
+}
diff --git a/src/lib/api/library/sync.ts b/src/lib/api/library/sync.ts
new file mode 100644
index 00000000..a55387bc
--- /dev/null
+++ b/src/lib/api/library/sync.ts
@@ -0,0 +1,124 @@
+/**
+ * Session + lifecycle commands (PR-5b) — bind/clear sync sessions, start/cancel
+ * syncs, mutate tracks, write artifacts/facts, purge. Split out of the former
+ * single `lib/api/library.ts`; re-exported via the `@/lib/api/library` barrel.
+ */
+import { invoke } from '@tauri-apps/api/core';
+import { serverIndexKeyForId } from './internal';
+import type {
+  PlaybackHint,
+  SyncMode,
+  SyncJobDto,
+  PurgeReportDto,
+  ArtifactInputDto,
+  FactInputDto,
+} from './dto';
+
+export function librarySyncBindSession(args: {
+  serverId: string;
+  baseUrl: string;
+  username: string;
+  password: string;
+  libraryScope?: string;
+}): Promise<void> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<void>('library_sync_bind_session', { ...args, serverId: indexKey });
+}
+
+export function librarySyncClearSession(serverId: string): Promise<void> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<void>('library_sync_clear_session', { serverId: indexKey });
+}
+
+export function libraryGetPlaybackHint(): Promise<PlaybackHint> {
+  return invoke<PlaybackHint>('library_get_playback_hint');
+}
+
+export function librarySetPlaybackHint(hint: PlaybackHint): Promise<void> {
+  return invoke<void>('library_set_playback_hint', { hint });
+}
+
+export function librarySyncStart(args: {
+  serverId: string;
+  mode: SyncMode;
+  libraryScope?: string;
+}): Promise<SyncJobDto> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<SyncJobDto>('library_sync_start', { ...args, serverId: indexKey })
+    .then(job => ({ ...job, serverId: args.serverId }));
+}
+
+/** Forced full-budget tombstone delta — Settings → «Verify integrity». */
+export function librarySyncVerifyIntegrity(args: {
+  serverId: string;
+  libraryScope?: string;
+}): Promise<SyncJobDto> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<SyncJobDto>('library_sync_verify_integrity', { ...args, serverId: indexKey })
+    .then(job => ({ ...job, serverId: args.serverId }));
+}
+
+export function librarySyncCancel(jobId?: string): Promise<void> {
+  return invoke<void>('library_sync_cancel', { jobId });
+}
+
+export function libraryPatchTrack(args: {
+  serverId: string;
+  trackId: string;
+  patch: {
+    starredAt?: number | null;
+    userRating?: number | null;
+    playCount?: number | null;
+    playedAt?: number | null;
+    /** E2: playback-derived `md5_16kb` content fingerprint. Normally written
+     *  by the Rust analysis bridge; exposed here for contract completeness. */
+    contentHash?: string | null;
+  };
+}): Promise<void> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<void>('library_patch_track', { ...args, serverId: indexKey });
+}
+
+/** Server favorites → `album.starred_at` (UPDATE only, no stub rows). */
+export function libraryReconcileAlbumStars(args: {
+  serverId: string;
+  starredAlbums: Array<{ id: string; starredAt: number }>;
+}): Promise<void> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<void>('library_reconcile_album_stars', {
+    serverId: indexKey,
+    starredAlbums: args.starredAlbums.map(a => ({ id: a.id, starredAt: a.starredAt })),
+  });
+}
+
+export function libraryPutArtifact(args: {
+  serverId: string;
+  trackId: string;
+  artifact: ArtifactInputDto;
+}): Promise<void> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<void>('library_put_artifact', { ...args, serverId: indexKey });
+}
+
+export function libraryPutFact(args: {
+  serverId: string;
+  trackId: string;
+  fact: FactInputDto;
+}): Promise<void> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<void>('library_put_fact', { ...args, serverId: indexKey });
+}
+
+export function libraryPurgeServer(args: {
+  serverId: string;
+  includeAnalysis?: boolean;
+  includeOffline?: boolean;
+}): Promise<PurgeReportDto> {
+  const indexKey = serverIndexKeyForId(args.serverId);
+  return invoke<PurgeReportDto>('library_purge_server', { ...args, serverId: indexKey });
+}
+
+export function libraryDeleteServerData(serverId: string): Promise<void> {
+  const indexKey = serverIndexKeyForId(serverId);
+  return invoke<void>('library_delete_server_data', { serverId: indexKey });
+}