ableton-lom

---
name: ableton-lom
description: Ableton Live Object Model (LOM) API reference for Python Remote Scripts and control surface development.
---

# Ableton Live Object Model (LOM) API Reference

This skill provides comprehensive documentation for the Ableton Live Python API used in Remote Scripts. The API is accessed through the `_Framework.ControlSurface` base class and provides programmatic control over every aspect of a Live Set.

## Quick Start

```python
from _Framework.ControlSurface import ControlSurface

class MyScript(ControlSurface):
    def __init__(self, c_instance):
        ControlSurface.__init__(self, c_instance)
        self._song = self.song()  # Access the Live Set (Song object)
        app = self.application()  # Access the Application object
```

## Core Objects Hierarchy

```
Application
├── browser (instruments, sounds, drums, audio_effects, midi_effects)
├── control_surfaces[] → ControlSurface
└── Song (live_set)
    ├── tempo, is_playing, loop, metronome
    ├── tracks[] → Track
    │   ├── clip_slots[] → ClipSlot → Clip
    │   ├── devices[] → Device → DeviceParameter
    │   ├── mixer_device → MixerDevice
    │   └── view → Track.View
    ├── return_tracks[] → Track
    ├── master_track → Track
    ├── scenes[] → Scene
    ├── cue_points[] → CuePoint
    ├── groove_pool → GroovePool → Groove
    ├── tuning_system → TuningSystem
    └── view → Song.View
```

## Reference Files by Domain

Load the appropriate reference file based on what you're working with:

| Domain | File | Use When |
|--------|------|----------|
| Song & Transport | [references/song.md](references/song.md) | Working with tempo, playback, time signatures, loops, cue points |
| Tracks | [references/track.md](references/track.md) | Creating/modifying tracks, routing, arm/solo/mute, meters |
| Clips & MIDI | [references/clip.md](references/clip.md) | Creating clips, adding/editing MIDI notes, clip properties, warping |
| Devices | [references/device.md](references/device.md) | Loading devices, accessing parameters, device chains |
| Specialized Devices | [references/specialized-devices.md](references/specialized-devices.md) | Simpler, Wavetable, Looper, Compressor, EQ8, Drift, etc. |
| Rack Devices | [references/rack.md](references/rack.md) | Instrument/Audio/MIDI/Drum Racks, chains, macros, drum pads |
| Session View | [references/session.md](references/session.md) | Scenes, clip slots, launching, Session View navigation |
| Views & UI | [references/views.md](references/views.md) | Application.View, Song.View, Track.View, Clip.View, Device.View |
| Browser | [references/browser.md](references/browser.md) | Browsing/loading instruments, effects, samples, presets |
| Control Surfaces | [references/control-surface.md](references/control-surface.md) | Accessing configured surfaces, grabbing controls/MIDI, SysEx |
| Grooves & Tuning | [references/grooves-tuning.md](references/grooves-tuning.md) | Groove pool, tuning systems |
| Coverage Checklist | [references/lom-coverage.md](references/lom-coverage.md) | Official Cycling '74 LOM object-to-file audit map |

## Key Concepts

### Property Access Modes
- **read-only**: Can only get the value
- **read-write**: Can get and set the value
- **observable**: Can add listeners with `add_<property>_listener(callback)`

### Threading
All state modifications MUST happen on Ableton's main thread:
```python
def modify_state():
    self._song.tempo = 120.0

self.schedule_message(0, modify_state)  # Schedule for main thread
```

### Canonical Paths
Objects are accessed via paths like `live_set tracks 0 devices 1 parameters 2`. Use these to understand the object hierarchy.

Special root paths include `live_set` (current Song), `live_app` (Application), `control_surfaces N` (configured ControlSurface), and `this_device` (the Device containing the Max for Live `live.path` object that receives `goto this_device`).

### Common Patterns

**Iterate tracks and clips:**
```python
for track in self._song.tracks:
    for slot in track.clip_slots:
        if slot.has_clip:
            clip = slot.clip
            # Work with clip
```

**Add a listener:**
```python
def on_tempo_changed():
    self.log_message("Tempo: " + str(self._song.tempo))

self._song.add_tempo_listener(on_tempo_changed)
```

**Access device parameters:**
```python
device = track.devices[0]
for param in device.parameters:
    self.log_message(param.name + ": " + str(param.value))
```

## Version Compatibility

This documentation covers **Live 12.3**. Key version notes:
- Live 11+: Python 3 required
- Live 11.0+: GroovePool, Groove classes added
- Live 12.3+: `insert_device()`, `insert_chain()`, AB Compare features added

## Important Notes

1. The API is officially undocumented by Ableton - this reference is based on community documentation from Cycling '74's Max for Live LOM reference
2. Always test Remote Scripts with a backup of your Live Set
3. Some operations may cause crashes if called from wrong thread
4. Observable properties can be used to build reactive UIs