Mosh

A native, cross-platform DAW with AI in the signal path — not bolted on.

Architecture · built by Emilio Sánchez-Harris

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Import/record, arrange, host VST3/AU plugins, mix, and export — plus a generative tier: an offline "re-imagine" / timbre-transform render layer with semantic controls that works on any track (MIDI/drum clips auto-bounce to audio first). An in-app agent (Moshi) and 2-player multiplayer ride on the same command spine.

macOS / Apple Silicon (arm64) is canonical. A Windows + NVIDIA/CUDA build is an additive, platform-guarded port — the full PC gate (native + CUDA + packaging + e2e) ran green on hardware on 2026-07-16. Linux (x86_64) is a CI-tracked headless spike (.github/workflows/linux-ci.yml); the GUI app is not a supported Linux target. The unified-memory MLX generative service is why the Mac stays the load-bearing target.

What it's made of

Three pieces behind one seam (the execute_command + snapshot/events contract):

• Native engine (src/, C++ / JUCE 8 + Tracktion Engine) — the audio engine, the MoshOps command spine (the single validated, undoable, audit-logged mutation path), and VST3/AU plugin hosting.
• WebView UI (ui/, React + Vite) — the arrangement/mixer/drawers, a pure client of MoshOps. Agents and the human UI execute the exact same commands.
• Generative service (service/, Python + MLX) — the offline Tier-B "re-imagine" model (Stable Audio 3), reached as a job over HTTP; falls back to a deterministic FakeAdapter when the model isn't installed.

Start here

Build & run

./run-mosh.sh build     # build (debug) and launch the GUI
./run-mosh.sh deploy    # build (release) and install one canonical /Applications/Mosh.app
./run-mosh.sh           # launch the already-built app
./run-mosh.sh smoke     # non-interactive native brain round-trip

Brain LLM keys (optional — typed agent requests fall back to an offline mock without them) go in ui/.env.local (see ui/.env.example). The generative model is wired with service/setup-sa3.sh.

Verify

/Applications/Mosh.app/Contents/MacOS/Mosh --selftest   # 1,000+ deterministic command-surface checks in the packaged app
cd ui && npm test && npm run test:e2e                   # UI units (vitest) + e2e (Playwright)

The hardware-verification runbook (does it make sound, record audio input, and sync two peers) lives in docs/VERIFICATION.md.

Status

v0.1.1 is out: a signed, notarized macOS (Apple Silicon) build on the releases page.

For the live engineering state, open PR dispositions, and ownership-transfer queue, read docs/CURRENT_STATUS.md.

License

Mosh is released under the GNU AGPL-3.0 (see LICENSE) — matching the open-source tiers of its foundations, JUCE 8 (AGPLv3) and Tracktion Engine (GPLv3 for open-source projects).