Ableton Extensions Skill

An Agent Skill that teaches an AI coding agent how to scaffold, write, build, and package Ableton Live extensions with the Ableton Extensions SDK (@ableton-extensions/sdk, TypeScript).

When this skill is installed, you can ask your agent things like "create an Ableton extension that transposes the selected MIDI clip up an octave" and it will produce a correct, buildable project using the real SDK APIs, conventions, and tooling — instead of guessing.

It follows the open Agent Skills convention — a SKILL.md file plus supporting reference docs — so any agent that understands that format can use it. Installation instructions below are for Claude Code; adapt the path for other agents that load skills.

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What it does

The skill gives the agent accurate, version-pinned knowledge of the SDK so it can:

• Scaffold a new extension project (manifest, build config, entry point).
• Write extension code using the real object model — tracks, clips, MIDI notes, devices, tempo, scenes, selections.
• Add UI — right-click context-menu actions, modal dialogs (WebView HTML), and progress dialogs.
• Build & package — bundle with esbuild and produce a distributable .ablx archive.
• Stay within the SDK's boundaries — it knows extensions are an offline editing/automation layer, not a real-time MIDI/audio effect (that's a job for Live's built-in MIDI effects or Max for Live).

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How it works

Agent Skills use progressive disclosure: a small always-loaded entry file points to larger references that the agent reads only when relevant. This keeps context lean.

ableton-extensions-skill/
├── SKILL.md                  # entry point — always loaded; frontmatter triggers the skill
├── README.md                 # this file (human-facing; not loaded by the agent)
└── reference/                # loaded on demand, when the agent needs the detail
    ├── scaffolding.md        # create a project, manifest/package/build configs, CLI, .env, debugging, packaging
    ├── api.md                # the full object model: ExtensionContext, Song/Track/Clip/MidiClip, enums, scopes
    └── recipes.md            # copy-paste code for context menus, dialogs, note/clip edits, transactions

• SKILL.md has YAML frontmatter (name, description). The agent reads the description to decide when to activate the skill (e.g. a request mentions an Ableton extension, MIDI clip editing, a context-menu action). Its body covers the entry-point shape, core concepts, and the workflow.
• reference/*.md are pulled in only when needed — e.g. the agent opens reference/recipes.md when writing a modal dialog, or reference/scaffolding.md when setting up the build.

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What you need to download / install

Requirement	Why	Where
Ableton Extensions SDK (extensions-sdk-<version>.zip)	the SDK library, CLI, scaffolder, docs, examples	ableton.com/en/live/extensions (beta program)
Ableton Live beta with Extensions support	to actually load/run extensions	from the Ableton beta / Centercode
Node.js ≥ 24.14.1	build tooling (esbuild, tsx, TypeScript)	nodejs.org
A code editor (VS Code recommended)	optional F5 debug integration	—

Note: Ableton Extensions are a beta feature. Access to the SDK and an Extensions-capable Live build is currently via Ableton's beta program — start at the link above.

This skill is built against SDK 1.0.0-beta.0 (API version 1.0.0). The reference docs point at a local unpacked SDK at C:\DEV\extensions-sdk-1.0.0-beta.0 (containing docs/, api/, examples/, and the .tgz tool packages). If you unpack the SDK elsewhere, update those absolute paths in SKILL.md / reference/scaffolding.md to match.

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Installing the skill

Skills are discovered from a skills/ directory. Copy this folder into one (rename it to match the skill name, ableton-extensions). The directory that contains SKILL.md becomes the skill.

Claude Code — personal (available in every project):

# Windows (PowerShell)
Copy-Item -Recurse C:\DEV\ableton-extensions-skill "$env:USERPROFILE\.claude\skills\ableton-extensions"

Claude Code — project-scoped (shared with a repo via git):

# from the project root
mkdir -p .claude/skills
cp -r /path/to/ableton-extensions-skill .claude/skills/ableton-extensions

After copying, the skill activates automatically when your request matches its description; in Claude Code you can also invoke it explicitly with /ableton-extensions.

Other agents: if your agent supports the Agent Skills (SKILL.md) format, place this folder in that agent's skills directory instead. The skill content itself is agent-agnostic — only the install location differs.

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Using it

Once installed, just describe what you want. Examples:

• "Scaffold a new Ableton extension called clip-doubler."
• "Add a right-click action on MIDI clips that humanizes note velocities."
• "Make a modal dialog to pick a chord type, then turn each note in the selected clip into that chord."
• "Build and package my extension into an .ablx."

The agent will follow the SDK's canonical patterns: an activate() entry point, initialize(activation, "1.0.0"), registerCommand + registerContextMenuAction, handle resolution with getObjectFromHandle, and withinTransaction for batched, single-undo edits.

Worked example (validated)

This skill was used to build a working One Note Chords extension (right-click a MIDI clip → choose a chord in a dialog → every note becomes that chord). The full toolchain was verified end-to-end: npm install → npm run build (typecheck + esbuild bundle) → npm run package (.ablx).

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Capabilities & limitations

Good for (what extensions do): transforming clips and MIDI notes at edit time, batch-editing tracks/devices/scenes, importing files, rendering audio from the arrangement, and adding context-menu tools, dialogs, and progress UI.

Not for (hard boundary): real-time processing. Extensions have no MIDI/audio stream callbacks — they are not devices in the signal chain and only act when the user triggers a command. For real-time transformations like "play one key, hear a chord," use a MIDI effect device (Live's built-in Chord device, or a Max for Live device), not an extension.

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Contributing

Contributions are very welcome! This skill is only as good as its accuracy and coverage, so feel free to:

• Fix or sharpen anything in SKILL.md or the reference/ docs (especially mismatches with the real SDK).
• Add recipes for common tasks, or share example extensions built with the skill.
• Keep it current as the Extensions SDK evolves (new API versions, renamed APIs, new capabilities).

Open an issue or a pull request — small corrections are just as appreciated as big additions. If you change anything API-related, please verify it against the SDK's type definitions or a real build before submitting.

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Sources & references

• Ableton Extensions (official): https://www.ableton.com/en/live/extensions
• Bundled SDK docs (in the SDK zip): docs/ — getting-started, essentials, development, design
• Bundled API reference: api/ — TypeDoc HTML for every class, interface, enum, and type
• Bundled examples: examples/ — context-menu, modal-dialog, progress-dialog, audio-clips, arrangementselection, warpMode, strip-silence
• Tooling packages (in the SDK zip): @ableton-extensions/sdk, @ableton-extensions/cli, @ableton-extensions/create-extension

The reference files in this skill are distilled from those sources and verified against the actual SDK type definitions.