A lullaby written for one child.

Slow tempo (around 60 to 70 beats a minute, roughly a resting heartbeat), a narrow melody that does not jump, a few instruments — piano, soft guitar, a music box, a hum — and words that repeat. The name should come back in every chorus, because a child hears their own name before they understand anything else in the song.

Tell the engine all of that in plain words: “very slow, soft, gentle, repetitive, quiet piano, no drums”. Say no drums explicitly; it is the single instruction that most changes the result.

Slow, soft, repeat the name. Say “no drums”.

• very slow gentle lullaby for baby Noah, soft female voice, quiet piano and a music box, no drums, repeats his name and “close your eyes” in every chorus
• soft acoustic guitar lullaby for Amara, warm male voice, the moon over the garden, her stuffed rabbit, slow and sleepy, no drums
• instrumental lullaby, music box and strings, 65 BPM, dreamy, fades out slowly, no vocals
• bedtime song for twins Leo and Mia, hummed female vocal, stars counting down, very quiet, repetitive, no percussion
• lullaby in Spanish for Sofia, soft female voice, la luna, sueños, slow and tender, no drums

If a version comes out too lively, run it again with “even slower, quieter, half the instruments” added to the prompt.

The lullaby most parents want is one they sing themselves — without having to be a singer. In the Android app, MY VOICE records you for about a minute and builds a model that can sing the lullaby in your voice, in tune and on time. It is the same voice the child hears at bedtime, just on the nights you are travelling or asleep first.

Download the MP3 to your phone and put it in a playlist that loops, or play it from a speaker at low volume rather than from the phone next to the crib. Keep the volume low; a lullaby is background, not foreground. Two or three versions in rotation stop the novelty from wearing off for you, and the child will not mind the repetition — repetition is the point.

Lullaby lyrics are the easiest ones to write: four short lines, the name in the last line, repeated. Paste them under a [Chorus] tag, add one [Verse] about their day if you like, and let Octa sing them exactly. Avoid words with hard consonant clusters at the end of lines; open vowels (“moon”, “day”, “slow”) are easier to sing softly. More in the lyrics guide.