ableton-humanize

name	Ableton Humanize
description	This skill should be used when the user asks to "humanize this MIDI", "add swing", "apply a groove", "make it less robotic/quantized", "loosen the timing", or "shape the velocities" of an existing MIDI clip in Ableton Live. Reads a clip's notes and rewrites them with micro-timing, swing, and velocity dynamics.
version	0.1.0

Ableton Humanize

Make stiff, grid-locked MIDI feel played-by-a-human by reading an existing clip and rewriting its notes with micro-timing offsets, swing, and velocity dynamics. The "lazy" lofi feel and a tight funk pocket are both just controlled deviations from the grid.

When to use

Triggers: "humanize", "add swing/groove", "less robotic", "shape velocities". To generate new parts use the composition/groove skills; this one transforms an existing clip.

Process

1. Use ableton-live-runner for build/run/kill + scaffold.
2. Read the target clip's notes (clip.notes). Operate in place (rewrite the same clip) or write a humanized copy — confirm which with the user.
3. Apply transformations (let the user pick intensity; keep it subtle by default):
   • Timing jitter — nudge each note startTime by a small random offset (±0.005–0.02 beats).
   • Swing — push notes on off-beat subdivisions later (8th swing: +0.04–0.08; 16th swing smaller). Decide the subdivision from the note grid.
   • Feel offset — a constant lean: drag the whole part slightly late (laid-back) or early (on top). Drums often want snare-late, kick-on.
   • Velocity dynamics — accent strong beats, soften off-beats/ghosts; add ±gentle variation; optionally a slow swell across a phrase.
   • Duration variation — vary note lengths slightly (legato vs staccato) for realism.
4. Clamp — keep startTime >= 0, velocities in 1–127, and don't let jitter create flams unless wanted. Write the array back with clip.notes = newNotes.

Code pattern

const rand = (a) => (Math.random() * 2 - 1) * a;
function humanize(notes, { jitter = 0.012, swing = 0.06, velVar = 6, drag = 0 } = {}) {
  return notes.map(n => {
    const isOff = Math.round((n.startTime % 1) * 2) % 2 === 1; // on an 8th off-beat?
    return {
      ...n,
      startTime: Math.max(0, n.startTime + rand(jitter) + drag + (isOff ? swing : 0)),
      velocity: Math.max(1, Math.min(127, Math.round((n.velocity ?? 90) + rand(velVar)))),
    };
  });
}

Limits

• This shifts note events, not Ableton's Groove Pool (no groove-template API). For consistent swing across many clips, consider baking the same offsets.
• Over-humanizing muddies tight genres — default to subtle, increase on request.

See ableton-drum-groove, ableton-topline.