yellowjacket/.planning/REQUIREMENTS.md

Requirements: YellowJacket

Defined: 2026-03-06 Core Value: The music player works reliably and feels solid — every interaction is correct, responsive, and trustworthy.

v1.1 Requirements

Requirements for v1.1 Features & Extensibility milestone. Each maps to roadmap phases.

Scan Cancellation

• SCAN-01: User can cancel an in-progress library scan via a cancel button
• SCAN-02: Cancelled scan stops gracefully without corrupting the database
• SCAN-03: User can pause a library scan and resume it without re-scanning processed files

Keyboard Shortcuts

• KEY-01: Default keybindings work out of box (play/pause, next/prev, volume, search focus, queue toggle, shuffle, repeat)
• KEY-02: User can customize all keyboard shortcuts via a visual settings UI
• KEY-03: Shortcut conflicts are detected and warned about when rebinding
• KEY-04: Shortcuts are scoped — different bindings apply based on focused component (track list vs player vs global)
• KEY-05: Shortcuts are disabled when text input has focus (except Escape to blur)

Tag Editing

• TAG-01: User can edit a single track's metadata (title, artist, album, genre, year, track number)
• TAG-02: User can batch edit multiple selected tracks' shared fields
• TAG-03: Tag changes are written to actual audio files (MP3 via ID3v2, FLAC via Vorbis Comments)
• TAG-04: Database and FTS5 search index update after tag writes without requiring a full rescan
• TAG-05: User can set or replace embedded cover art from an image file
• TAG-06: Tag writes use write-to-temp-then-rename to prevent file corruption
• TAG-07: Tag editing is blocked for currently-playing files (queued for after playback stops)

Smart Playlists

• SMRT-01: User can create a smart playlist with filter rules (genre, year, artist, album, title)
• SMRT-02: Multiple rules combine with AND logic
• SMRT-03: User can set random ordering and result limit ("Random 50 Jazz tracks")
• SMRT-04: Smart playlists appear in the sidebar alongside regular playlists
• SMRT-05: Smart playlist rules are persisted and survive app restart

Gapless Playback

• GAP-01: Tracks transition seamlessly with no audible silence gap (gapless playback)
• GAP-02: Next track is pre-decoded before current track ends
• GAP-03: User can enable/disable crossfade with configurable duration (1-10 seconds)
• GAP-04: Crossfade only applies on auto-advance, not manual skip

MusicBrainz Browser

• MB-01: User can search for artists by name and view results
• MB-02: User can browse an artist's discography (release groups — albums, EPs, singles)
• MB-03: User can view tracks on a specific release
• MB-04: User can view different editions of a release group (pressings, reissues)
• MB-05: API responses are cached in SQLite (24hr for searches, 7 days for entities)
• MB-06: Album cover art is displayed from the Cover Art Archive
• MB-07: Rate limiting (1 req/sec) is enforced with proper User-Agent header

Layout Customization

• LAYOUT-01: User can resize sidebar and queue panels via drag handles
• LAYOUT-02: Panel sizes persist across app restarts
• LAYOUT-03: User can show/hide sidebar sections and queue panel
• LAYOUT-04: User can choose which component is displayed in each layout section (MusicBee-style)
• LAYOUT-05: Components declare size constraints (min/max dimensions, aspect ratio compatibility)
• LAYOUT-06: Layout presets available (Compact, Full, Mini player) with quick switch

Plugin System

• PLUG-01: Plugin API is defined — plugins can access events, player state, queue, library data
• PLUG-02: JS/TS plugin bundles are loaded from user plugin directory at runtime
• PLUG-03: Plugins can register UI components into the layout system
• PLUG-04: Plugin manifest file defines name, version, permissions, hooks, and UI components
• PLUG-05: Plugins can have their own persistent configuration
• PLUG-06: One example plugin ships demonstrating the API

Future Requirements

Deferred to future milestones. Tracked but not in current roadmap.

Tag Editing (v2+)

• TAG-F01: Undo/redo for tag edits
• TAG-F02: Auto-capitalize and clean tag values
• TAG-F03: Filename-to-tag inference (parse "Artist - Title.mp3" patterns)
• TAG-F04: Tag-to-filename rename based on template

Smart Playlists (v2+)

• SMRT-F01: Play count tracking for smart playlist rules
• SMRT-F02: Rating system for smart playlist rules
• SMRT-F03: OR logic and nested boolean groups
• SMRT-F04: Sort order control in rule definition
• SMRT-F05: Auto-update smart playlists on library changes

Gapless Playback (v2+)

• GAP-F01: Per-album gapless (disable crossfade within albums)
• GAP-F02: ReplayGain normalization
• GAP-F03: Fade-in on play, fade-out on pause

MusicBrainz Browser (v2+)

• MB-F01: Link local tracks to MusicBrainz recordings (MBID association)
• MB-F02: Search recordings (find specific songs across releases)

Layout Customization (v2+)

• LAYOUT-F01: Detachable panels (pop out to separate window)

Plugin System (v2+)

• PLUG-F01: Plugin marketplace/registry for discovery and installation
• PLUG-F02: Dynamic Go plugin loading for backend extensions
• PLUG-F03: Plugin permissions and sandboxing model

Out of Scope

Explicitly excluded. Documented to prevent scope creep.

Feature	Reason
OGG Vorbis tag writing	No mature pure-Go write library exists
WAV metadata editing	Rarely needed, low priority
Auto-tag from MusicBrainz	Complex matching logic — Picard's domain, not a browser feature
Write data to MusicBrainz	Requires OAuth and community guidelines compliance
DSP effects chain (equalizer, reverb)	Scope explosion — separate feature area
Go plugin package for backend plugins	Linux-only, version-fragile, widely considered broken
Free-form drag-and-drop layout	Overwhelming complexity; section-based approach is better
Global OS-level hotkeys	Platform-specific, conflicts with OS shortcuts; MPRIS2 handles media keys
Mobile-responsive layout	Desktop app with fixed minimum size
Plugin binary distribution	Source-based (JS bundles) is safer and more portable

Traceability

Which phases cover which requirements. Updated during roadmap creation.

Requirement	Phase	Status
SCAN-01	Phase 9	Complete
SCAN-02	Phase 9	Complete
SCAN-03	Phase 9	Complete
KEY-01	Phase 9	Complete
KEY-02	Phase 9	Pending
KEY-03	Phase 9	Pending
KEY-04	Phase 9	Complete
KEY-05	Phase 9	Complete
TAG-01	Phase 10	Pending
TAG-02	Phase 10	Pending
TAG-03	Phase 10	Pending
TAG-04	Phase 10	Pending
TAG-05	Phase 10	Pending
TAG-06	Phase 10	Pending
TAG-07	Phase 10	Pending
SMRT-01	Phase 11	Pending
SMRT-02	Phase 11	Pending
SMRT-03	Phase 11	Pending
SMRT-04	Phase 11	Pending
SMRT-05	Phase 11	Pending
GAP-01	Phase 12	Pending
GAP-02	Phase 12	Pending
GAP-03	Phase 12	Pending
GAP-04	Phase 12	Pending
MB-01	Phase 13	Pending
MB-02	Phase 13	Pending
MB-03	Phase 13	Pending
MB-04	Phase 13	Pending
MB-05	Phase 13	Pending
MB-06	Phase 13	Pending
MB-07	Phase 13	Pending
LAYOUT-01	Phase 14	Pending
LAYOUT-02	Phase 14	Pending
LAYOUT-03	Phase 14	Pending
LAYOUT-04	Phase 14	Pending
LAYOUT-05	Phase 14	Pending
LAYOUT-06	Phase 14	Pending
PLUG-01	Phase 14	Pending
PLUG-02	Phase 14	Pending
PLUG-03	Phase 14	Pending
PLUG-04	Phase 14	Pending
PLUG-05	Phase 14	Pending
PLUG-06	Phase 14	Pending

Coverage:

• v1.1 requirements: 43 total
• Mapped to phases: 43
• Unmapped: 0 ✓

---

Requirements defined: 2026-03-06 Last updated: 2026-03-06 — traceability updated with phase mappings