# Ableton Live Runner > This skill should be used when the user asks to "drive Ableton from code", "run an Ableton extension", "set up the Ableton SDK", "compose into Ableton Live", "write MIDI into Live", or whenever any other ableton-* skill needs to actually build, run, and connect an Extension SDK project to Ableton Live. Provides the SDK setup, API cheatsheet, beta gotchas, the reusable extension scaffold, and the… - **Type:** Skill - **Install:** `agentstack add skill-korben00-ableton-producer-skills-ableton-live-runner` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [Korben00](https://agentstack.voostack.com/s/korben00) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [Korben00](https://github.com/Korben00) - **Source:** https://github.com/Korben00/ableton-producer-skills/tree/master/skills/ableton-live-runner ## Install ```sh agentstack add skill-korben00-ableton-producer-skills-ableton-live-runner ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Ableton Live Runner The foundation skill for driving Ableton Live via the **Extension SDK** (JS/TS automation that runs in a Node process beside Live). Every other `ableton-*` skill produces a *composition function*; this skill is responsible for getting that code to actually run inside Live, reliably, despite the beta's rough edges. ## When to use Use this skill whenever Ableton work needs to reach the running app: scaffolding the runner project, inserting devices, writing clips, rendering audio, or recovering from a failed connection. The content/musical-logic skills (genre-cover, reharmonize, bassline, drum-groove, etc.) all assume this skill's workflow and helpers. ## Prerequisites (verify first) 1. Ableton Live 12 is **open** (Suite gives the full device set; everything falls back to `Drift`). 2. **Developer Mode is ON**: Live → Preferences → Extensions → Developer Mode. **It resets to OFF on every Live restart — re-check it each time.** 3. A runner project exists (an Extension SDK project with `src/extension.ts`, `npm start` = build + `extensions-cli run`, and `.env` pointing `EXTENSION_HOST_PATH` at `ExtensionHostNodeModule.node`). To start a new one, copy `examples/extension-template.ts` into the project's `src/extension.ts`. ## Core workflow The single most important rule: **get the code right before running**, because each run effectively costs a Live restart (see gotchas — one reliable activation per session). 1. **Write/patch** `src/extension.ts` (use the scaffold in `examples/extension-template.ts`; drop the musical logic from the relevant skill into `compose()`). 2. **Build to typecheck**: `npm --prefix run build:dev` — fix any TS error before running. 3. **Kill stale host** (always, between runs): ```bash pkill -f "ExtensionHostNodeModule"; pkill -f "extensions-cli run"; pkill -f " start" ``` 4. **Run** in the background and watch the log: ```bash npm --prefix start > /tmp/ableton-run.log 2>&1 & ``` 5. **Diagnose the log** (this is where the two failure signatures matter): - Lines `sends greeting` → `cannot send now` → `send success` → then `[ext]: ...` and `Done.` = ✅. - Host logs `Started: Extension Host` then **nothing** = **Developer Mode is OFF** → ask the user to enable it, then re-run. - `send success` appears but **no** `activate()` output = the once-per-session activation bug → the only reliable fix is **restart Ableton Live**, then re-run on the fresh session. 6. **Kill the host** when done (`pkill` as above) to leave a clean state for the next run. ## Reusable helpers (in the scaffold) - `makeTrack(song, name, instruments, fxSlots, notes, lengthBeats)` — creates a MIDI track, inserts the first instrument that loads (end the list with `"Drift"`), inserts one FX per slot (each slot a fallback list), then writes the clip notes. - `clearPriorTracks(song)` — idempotent re-runs: deletes tracks whose names are in `TRACK_NAMES`, re-reading `song.tracks` each pass (deleting invalidates handles). Call it before creating tracks. - `setParam(track, deviceName, paramName, value)` — dial a device knob via `DeviceParameter.setValue`. - `vary(base, spread)` — velocity humanization; `inRanges(bar, ranges)` — section gating. ## Key constraints to design around - `insertDevice` loads **default presets only** (no browser presets/kits). `Drum Rack` is empty/silent → tell the user to drag a kit. Get timbre via the right native device + `setParam`. - **No `File → New`** and `song.tempo` is global → keep different songs in **different Sets**; make re-runs idempotent with `clearPriorTracks`. - Note times are **beats, clip-local**. Setting the whole `clip.notes` array at once is atomic/fast. - **No automation curves** and **no real-time/transport** — this is composition/arrangement, not live performance. ## Additional resources - **`references/gotchas.md`** — the full list of beta failure modes (connection, activation, devices, handles, timing). Read this whenever something silently fails. - **`references/sdk-api.md`** — API cheatsheet: Song/Track/Clip/Device/Resources/UI surface, the `NoteDescription` shape, working device names, MIDI/GM-drum constants. - **`examples/extension-template.ts`** — the proven scaffold with all helpers; the starting point for every composition skill. ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [Korben00](https://github.com/Korben00) - **Source:** [Korben00/ableton-producer-skills](https://github.com/Korben00/ableton-producer-skills) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** yes - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-korben00-ableton-producer-skills-ableton-live-runner - Seller: https://agentstack.voostack.com/s/korben00 - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.