Features and current status

Note. This page's header line records when the inventory was first written. The tables name the release each row shipped in, and several rows are newer than that header (0.3.0-alpha.275 … .278).

Written against 0.3.0-alpha.272 (2026-11-01). This page is the consolidated inventory: what the app can do today, what is only partly there, and what is agreed but not built. PROGRESS.md records what each release changed; this page answers "what is in it, right now".

How to read the state column

word	meaning
shipped	in the packaged build, covered by the test suites
partial	it works, with a limit named in the row
planned	agreed and written down, not built
not built	deliberately dropped (with the reason recorded)
unverified	written, but never run on the target (say so, never claim it works)

Evidence names the module, file or document that proves the claim — every row can be checked.

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1. Platforms and packaging

Feature	What it does	State	Evidence
Windows build	MSVC, Qt 6.8, packaged app + setup.exe	shipped	tools/package.ps1, tools/installer.iss
Windows installer	per-user install (no admin prompt), Start Menu entry, uninstaller; verified by silent install → run → uninstall	shipped	tools/make_installer.ps1, docs/implementation/building.md
Portable Windows zip	dist/Nebula-<version>/ + .zip, latest version only	shipped	tools/package.ps1 (keep-1 prune)
Linux build	GCC, Qt 6.8 (aqtinstall), tests + app	shipped	.gitea/workflows/ci.yml, references/wsl-linux-verification.md
Linux .deb	installs to /opt/nebula, menu entry, nebula command, bundles its own Qt; verified by install → run → remove	shipped	tools/make_installer_linux.sh
Linux portable .tar.gz	the same tree, unpack anywhere	shipped	same script
macOS .dmg	macdeployqt bundle + disk image script	unverified — no Mac in the toolchain, no CI job	tools/make_installer_macos.sh (its own header says so)
macOS MIDI input	—	not built (Windows uses WinMM, Linux ALSA; no CoreMIDI)	docs/plan/keyboard-shortcuts.md, HANDOFF
Headless project render	render a saved .nebproj to WAV with no window	shipped (example tool)	examples/render_project_file.cpp

2. The app's surfaces

Feature	What it does	State	Evidence
Timeline (arrangement)	tracks, clips, drag/move, split, quantise, zoom, loop range, playhead	shipped	app/TimelineView.qml, PianoRoll.qml
Clip Launcher (Session)	scene grid, clip triggers, launch quantise, per-clip loop	shipped	app/SessionView.qml
Mixer	channel strips, faders, pan, meters, groups, returns, master	shipped	app/MixerView.qml
Node view	build your own instrument by wiring modules (NOSI graph)	shipped	app/NodeView.qml, docs/plan/node-view-and-nosi.md
Browser panel	instruments, effects, samples, content library, search	shipped	app/BrowserPanel.qml
Detail panel + cards	per-track cards: Instrument, Devices/FX, Note Effects, Analyser, Mastering, Automation, Log	shipped	app/DetailPanel.qml + *Card.qml
Command palette	Ctrl+K action list with shortcuts	shipped	app/CommandPalette.qml
Settings sheet	11 pages: appearance, audio, MIDI, instrument, local API, export, logging, project, bug report, keys & shortcuts, about	shipped	app/SettingsPanel.qml + sections
Themes	built-in themes + user theme folder + import/export; contrast-checked	shipped	app/theme/*, tools/check_docs.py theme rules
Help strip	hover help for every control ("point at anything")	shipped	app/Main.qml
Translations	i18n skeleton + string externalisation	partial (skeleton; strings extractable, no shipped translations yet)	tools/translations.ps1
Accessibility	accessible names/roles on controls, checked by a guard	shipped	check_qml_accessible guard
Crash report dialog	in-app report to the project's endpoint, with a key	shipped	bug-report settings page, docs/plan/distribution-and-support.md

3. Instruments

Feature	What it does	State	Evidence
Modular synth voices	93 lead/key patches (Modular Lead, Square Lead, Acid Saw, Tine E-Piano, …)	shipped	plugins/src/patch.cpp (voice_patch)
Bass patches	64 bass patches (Sub Bass, 808 Sub, Minimoog Bass, Motown Bass, Bass Guitar, …)	shipped	same (categorised_voice("bass", …))
Pad patches	61 pads (Warm Strings, Glass Pad, Aurora Pad, Choir Pad, …)	shipped	same (pad_patch)
FM instruments	45 FM patches (FM E-Piano, FM Bell, FM Bass, FM Brass, …)	shipped	same (fm)
263 factory patches total, four families	—	shipped	factory_patches()
Sampler	one sample per track, root note, tune, attack/release, loop, start/end	shipped	app/SamplerCard.qml, nebula.services.kSamplerInstrument
Drum Rack	16 pads, per-pad sample + gain/tune/release/start/end, choke groups, kit load/save (.nebkit), slice-a-sample to pads	shipped	app/DrumRackCard.qml, services/src/track_instrument.cpp
Instrument Rack	layered instruments with per-layer gain, level control, add/remove/reorder layers	shipped	app/RackCard.qml
24 drum-machine kits	606, 707, 808, Acid, Breaks, Cinematic, Deep House, Drum and Bass, Electro, Funk, Garage, Hip-Hop, Jazz, Jungle, Kitchen Keys, Latin, Minimal, Orchestral, Percussion, Reggae, Rock, Techno, Trance, Trap	shipped	dist/…/patches/*Kit.nebpatch
292 patch files ship with the build	factory patches + ready-made presets	shipped	dist/…/patches/
Per-instrument presets	save/load a patch's knob settings (.nebpatch)	shipped	app/PatchFilesSection.qml
Rhytmix	voice-to-MIDI (sing → notes), chord naming with plain-English explanation, next-chord suggestions, Play chords / inversions / voicings (block, strum, arpeggio, humanized), Scale lock, Hold, Strum	shipped	app/RhytmixCard.qml
Groover	take the groove of one clip (Copy / Humanize / Shuffle / Auto / Templates) and write a new clip with that feel	shipped	app/GrooverCard.qml, app/src/groover_controller.cpp
Step sequencer + grids	melodic step grid, drum grid, synth grid, piano roll	shipped	app/StepSequencer.qml, PianoRoll.qml

4. Effects

33 built-in effects (plugins/src/device_preset.cpp → track_effect_ids()), all with factory presets and per-effect preset save/load:

Group	Effects
Time	nebula.delay, nebula.pingpong, nebula.comb, nebula.stutter, nebula.haas
Space	nebula.reverb, nebula.convolutionreverb
Tone	nebula.eq, nebula.autofilter, nebula.tremolo, nebula.autopan, nebula.vibrato
Dynamics	nebula.compressor, nebula.multibandcompressor, nebula.gate, nebula.expander, nebula.transientshaper, nebula.deesser, nebula.limiter, nebula.lookaheadlimiter, nebula.utility
Drive / colour	nebula.distortion, nebula.saturator, nebula.wavefolder, nebula.bitcrusher
Modulation / pitch	nebula.chorus, nebula.flanger, nebula.phaser, nebula.ringmod, nebula.octave, nebula.pitchshifter, nebula.vocoder, nebula.granular

Feature	What it does	State	Evidence
Per-track effect chains	add / remove / reorder / bypass, per-device preset	shipped	app/DevicesPanel.qml, devices.* API
Master chain	the same chain on the master, with a mastering card and a Key row	shipped	app/MasteringCard.qml
Sidechain / key	any keyable device can be keyed from another track (compressor ducking, gates); works offline and live, on tracks, buses and the master	shipped (0.3.0-alpha.270–272)	services/src/sidechain_plan.cpp, tests/services/test_sidechain*.cpp
Latency compensation	devices that report latency (look-ahead limiter) are aligned; PDC across tracks	shipped	nebula.lookaheadlimiter (latency_samples()), engine PDC tests
Note effects	per-track MIDI note-effect chains (arp/scale/etc.) with a picker and settings	shipped	app/NoteEffectsCard.qml
Analysers	spectrum + loudness readings from the real render	shipped	app/AnalyserCard.qml

5. The audio engine

Feature	What it does	State	Evidence
Audio backends	WASAPI (Windows), ALSA (Linux), device pick, sample rate, buffer size, exclusive mode	shipped	docs/implementation/asio.md, settings audio.*
Audio input	record and monitor an input, audio tracks and audio clips	shipped	addAudioClip, app/AudioSection.qml
Transport	play/stop, metronome, loop range, position, tempo	shipped	TransportBar.qml, transport.* API
Tempo map	tempo events, beat ↔ sample conversion	shipped	TempoMap, project_file tempo_events
Offline render	render the project (whole or a range) to audio, run-to-run bit-identical	shipped	services/src/project_renderer.cpp, docs/adr/0022-project-to-audio-bridge.md
Live backing render	the app renders what you hear in the background and swaps it in	shipped	app/src/render_worker.cpp
Live device state across rebuilds	editing a knob no longer restarts a device: delay tails, envelope levels, oscillator phase and held notes survive a palette rebuild	shipped on Windows (0.3.0-alpha.272); open Linux defect — see below	engine/include/nebula/engine/node_cache.h, tests/engine/test_node_cache.cpp
Real-time safety	no locks on the audio callback (audited, mutex by mutex), NEBULA_NONBLOCKING annotations, allocation-tripwire tests on Windows, RealtimeSanitizer + ThreadSanitizer jobs on Linux	shipped	docs/architecture/rt-lock-audit.md, tests/core/test_rt_safety.cpp
Multi-core render scheduler	the offline renderer renders independent tracks at once, in waves that respect sidechain keys, and sums in one fixed order; the thread count cannot change the samples (measured 3.58x on four cores, 691 ms -> 193 ms)	shipped (0.3.0-alpha.275)	engine/include/nebula/engine/render_pool.h, services/src/project_renderer.cpp, ADR-0028
Export	WAV (16/24/32-bit) and MP3 (LAME loaded at run time, never linked)	shipped	engine/src/audio_file.cpp, libmp3lame.dll in the package

6. The project model and files

Feature	What it does	State	Evidence
Command bus + undo/redo	every edit is a command, undoable, with history info	shipped	model/src/command_bus.cpp, history.* API
Project file .nebproj	versioned JSON, unknown-field preservation, migrations	shipped	model/src/project_file.cpp
Autosave + crash recovery	auto-saved copy restored after a kill, with a recovery dialog	shipped	projects/recovery.nebproj, app/Main.qml recover dialog
Atomic writes + rolling backups	a kill during a save cannot corrupt the file; .bak1, .bak2, …	shipped	core::write_file_atomically, rotate_project_backups
Command-replay journal	—	not built (deliberately: atomic writes + recovery already meet the criterion)	docs/plan/phases.md P3 note (AC-0281/AC-0283)
Kit file .nebkit	save/load a Drum Rack's pads, relocatable	shipped	saveKitToFile / loadKitFromFile
Settings file	only non-default values are stored; portable with --data-dir	shipped	core/src/settings.cpp
Sample import	drag a WAV into the Sampler / a Drum Rack pad; slices	shipped	tracks.setSamplerSample, sliceToDrumRack

7. Automation and performance helpers

Feature	What it does	State	Evidence
Automation curves	draw a knob's curve on a lane, per track	shipped	app/AutomationLane.qml
Automation recording	arm knobs, record a pass while the transport runs, written back into curves	shipped	app/AutomationPanel.qml, sampleArmedKnobs
Clip swing	per-clip swing amount	shipped	clips.setSwing
Humanize / feel	via Groover templates	shipped	groover_controller.cpp
Scale lock / chord modes	keep notes in key, one key = a chord, inversions and voicings	shipped	RhytmixCard.qml

8. MIDI

Feature	What it does	State	Evidence
MIDI input	several keyboards at once, hot-plug, per-device enable	shipped	app/MidiSection.qml
Hardware mapping	a unified CC map shared by all devices, learn-by-moving	shipped	settings midi.cc_map
Computer keyboard	play notes from the typing keyboard (A–K, Z/X octave)	shipped	PianoKeys.qml, help strip
MIDI out	the notes the song plays and the 24-ticks-a-beat clock go out of a chosen MIDI port, so external gear plays along and follows the transport; Start/Continue/Stop with the transport	shipped (0.3.0-alpha.274)	engine/include/nebula/engine/midi_out_queue.h, engine/src/midi_winmm.cpp / midi_alsa.cpp, app/src/midi_controller.cpp, ADR-0027
MIDI out — not built	per-track routing to different ports, CC automation on the way out, clock input, timing finer than the 4 ms drain	planned (Phase 11)	ADR-0027

| MIDI clock input | Nebula follows external gear: pick an input as the clock source and the transport follows start/continue/stop, song position and the smoothed tempo; free-running when the clock stops | shipped (0.3.0-alpha.278) | ADR-0030 | | MTC | MIDI Timecode in and out, including exact 29.97 drop-frame, with a frame-rate setting | shipped (0.3.0-alpha.278) | ADR-0030 | | Program change + per-track MIDI channel | program change in selects a track's preset and out is emitted when it changes; each track has its own MIDI channel | shipped (0.3.0-alpha.278) | ADR-0030 | | MPE | per-note member channels: each note keeps its own bend/pressure/CC74 with its own voice, +/-48 semitones, in and out | shipped (0.3.0-alpha.278) | ADR-0031 | | Lua controller scripts | a sandboxed Lua 5.4.8 host that turns MIDI input into actions through MIDI learn's own path; scripts folder + enable switch + Reload | shipped (0.3.0-alpha.278) | ADR-0031 | | Multi-core LIVE mixer | playback renders independent tracks in parallel waves on a real-time-safe fork/join; the mix is bit-identical at any thread count (3.13x measured) | shipped (0.3.0-alpha.278) | ADR-0028 |

9. The Control API, OSC and the AI/MCP path

Feature	What it does	State	Evidence
Local Control API	JSON-RPC 2.0 over a localhost socket, token-guarded, 64 methods (app.ping, project.*, tracks.*, clips.*, devices.*, transport.*, history.*, instruments.*), events pushed to the client (nebula/render.finished, nebula/project.changed)	shipped	docs/adr/0024-control-api-v1.md, app/src/api_controller.cpp
Off by default	the API is opt-in (settings → Local API), token generated per machine, localhost only	shipped	core/src/settings.cpp api.*
OSC door	the same actions over UDP for hardware controllers	shipped	api_server/src/osc.cpp
Every API action is a command	scripts get exactly the undoable edits the UI makes — an AI cannot do more than a script could	shipped	ADR-0023 rule 4
Headless render from a script	project.renderToWav renders in the background and reports the written path	shipped	api_controller.cpp
AI assistant plugin (chat panel that drives the app: compose from a prompt, arrange, mix, export, build instruments)	—	planned, closed-source add-on — deliberately outside the open repo	docs/plan/ai-plugin.md
MCP server	an MCP server as a client of the same API door	planned	ADR-0024 ("the MCP server as a client of this same door")

Fixed in 0.3.0-alpha.273 (was a measured limitation on 2026-11-01): instruments.list and devices.catalogue never answered — their replies are bigger than the 8 KiB wire line and, unlike other oversized replies, the error came back with "id": null, so a client matching replies by id waited for an answer that had already arrived. Two changes: the server now carries the request's id on every reply (including "the reply is too long" and an internal error), and both methods answer a page — {"instruments": [...], "total": 291, "offset": 0} — so offset += items.size() walks the whole catalogue. Measured on the fixed build: a 156-entry page in 0.02 s, 291/291 instruments walked, 33 devices in two pages; instruments.list also takes limit and withPresets (46 entries per page with presets). (api_server/src/api_server.cpp, app/src/api_controller.cpp, tests/api_server/test_api_server.cpp, tests/app/test_api_controller.cpp.)

10. Content library

Feature	What it does	State	Evidence
Content Library browser	presets, kits, one-shots, loops, demo projects from a library folder with an index.json	shipped	services/src/content_catalog.cpp, app/BundleCard.qml
One-shot bundle	the CC0 one-shot kit (33 sounds) generated into the data folder, exportable for publishing	shipped	--export-one-shots, examples/gen_one_shots.cpp
Kit loading	load a library kit onto a Drum Rack (copies its samples into the project)	shipped	loadContentKit
Starter library	2 kits, 4 one-shots, 2 presets, 1 demo project	shipped (sample library; the full library is a separate repo)	Nebula-Sound-System-Content-Library/index.json

11. Quality gates, CI and release discipline

Feature	What it does	State	Evidence
Test suites	Windows 1225 cases, Linux 907 (six Qt-free suites + the app suite)	shipped	tests/, PROGRESS.md
Performance gates	startup to first frame < 3000 ms, idle CPU < 1 %, RAM < 300 MB — measured every packaging run	shipped	tools/package.ps1 (measured 2174 ms / 0.55 % / 261 MB at alpha.272)
QML sweep	36 documented screens opened headlessly; any QML runtime error fails the package	shipped	tools/package.ps1 sweep list
Documentation guards	67 probes over the docs/layers/themes/shortcuts/API/…	shipped	tools/check_guards_selftest.py
Licence compliance	REUSE lint over every file (539/539 at alpha.272)	shipped	reuse lint
Fault plants	break a guard on purpose, prove the test catches it, restore	practice	recorded in PROGRESS.md per release
CI	Gitea Actions (Windows + Linux), local runs when the runner is busy	shipped	.gitea/workflows/ci.yml
Release discipline	one feature per release, an AC id per unit, CHANGELOG/PROGRESS/CHANGELOG-ARCH/HANDOFF updated, both remotes pushed with tag parity	practice	PROGRESS.md, docs/standards/versioning.md

12. Not built / known gaps (say these out loud)

Not a defect — an inconsistent incremental build (2026-11-02, explained the same day). One Linux build failed the two audible node-cache tail cases in tests/services/test_live_state.cpp (tail rms = 0 after a palette rebuild). A CLEAN build of the same sources passes (the whole services suite: 268 cases), as does a rebuild, and as does the code under ASan/UBSan at -O1 and -O3; Windows is green (1226/1226). The "adding a print fixes it" observation is explained: the print was in a HEADER (node.h), which forces every dependent translation unit to recompile and thereby repaired the inconsistent build. The mechanism: rsync -a preserves the Windows source mtimes, which can be OLDER than the WSL object files, so ninja silently skips rebuilding them and the mirror runs a binary that does not match its sources. Rule: rebuild cleanly before reporting a cross-platform failure; only a failure that survives a clean build is a code defect. The probe recipe stays in the repo skill (references/control-api-rig-and-capture.md) in case it ever returns.

Gap	Note
macOS	build script only; no Mac in the toolchain, no CI job, no CoreMIDI input, no signing/notarisation. Unverified, not claimed.
AI assistant plugin	planned, closed source, outside the open repo (docs/plan/ai-plugin.md).
MCP server	mcp/ — a stdio MCP server (Python, the official SDK) exposing 11 tools over the existing Control API; a render tool waits for nebula/render.finished and answers with the file. Verified against the running app (AC-0334)	shipped (0.3.0-alpha.276)	mcp/, ADR-0029
MIDI output — per-track ports, CC out, timing	SHIPPED (0.3.0-alpha.278): per-track output ports, CC 7/CC 10 automation out, clock input (see the rows below), and a configurable drain with measured jitter	shipped	ADR-0027, ADR-0034
Command-replay journal	deliberately not built (atomic writes + crash recovery cover the need).
Plug-in hosting	CLAP hosting SHIPPED (0.3.0-alpha.278): discovery, a host node with knobs/PDC latency/state, SEH containment. VST3 is NOT supported and cannot be (GPLv3-or-proprietary SDK vs FSL); LV2/AU and a plug-in GUI are not built. Out-of-process hosting (32-bit / foreign licences) ships as the bridge.	ADR-0032, ADR-0033
Translations	skeleton only; no translated UI ships yet.