Stuckato

Short bursts. Real progress. Couch to 5K for practising an instrument, on your own with a teacher or as part of a choir or orchestra. Your teacher sets the week in thirty seconds; Stuckato gets you to practise every day.

Live: https://stuckato.app

The idea

Every practice app is one of two things: it listens to you play and scores the notes (Yousician, Simply Piano, Trala), or it's a diary where you log your minutes (Tonara, Modacity). Both leave you alone on the part that matters, which is turning up three times a week when nobody is making you. Couch to 5K never measured anyone's running; it had a calm voice, a structure, and a reason to go out on Thursday. Nobody had done that for practising an instrument.

Stuckato has two sides. The teacher writes a thirty-second note after each lesson (what we worked on, what to prepare, one line for the week) and sets how many minutes a day; Stuckato turns it into that pupil's week: one short guided session for every day, with step-by-step captions in the teacher's voice, a work list, and a checklist for the next lesson. The pupil runs each day's session (or practises on their own and just ticks), then ticks what they worked on from the work list, flags questions and breakthroughs while they're fresh, and keeps a streak that forgives a missed day. Before the next lesson the teacher sees what was worked on most, and the next week is planned around it. A conductor does the same for a whole choir or orchestra: one rehearsal note becomes a week for every member, each for their own part.

Why not Yousician? Yousician is for people without a teacher: it listens through the phone, lights each note green or red against its own library, and covers guitar, piano, bass, ukulele and voice. Stuckato is for the six days between lessons, run by the teacher. The week is her note, in her voice, for the actual piece; the teacher sees what happened; violin, cello, wind, brass and choirs are in; the point is turning up on Wednesday, not scoring notes. Where Stuckato does listen (the week's passage, below), it compares the pupil to the teacher's own playing, points at the bars that differ, and leaves the judgement to her. Nobody else has the teacher in the loop.

What's in v0.11 (4 October 2026): backing tracks

Off for every pupil until the teacher switches it on in the pupil's page (pilot pupils stay as they were); add ?backing=1 to the URL to try it on any device. Pupils' tracks need the v0.10 SQL (the private bucket); the exam accompaniment also needs supabase/v0.11-backing.sql run once.

• Add a backing. The pupil records up to a minute (or uses the week's passage take they just made). Stuckato finds the key from the notes it hears and puts chords under it that follow the player: where the chords change and which chords they are are chosen together, every change costs a little, a dominant going home is rewarded, and a chord never runs across a pause, so it waits when they stop. Piano, strings, guitar or a warm pad, with a volume slider. If the key is unclear it asks, with its best guess picked.
• Play along. Headphones in, pick a style (piano ballad, strings, acoustic, lo-fi beat), a tempo (slider or tap) and a key (suggested from this week's passage), one bar of clicks, then the backing plays while they record. The recording is taken in the same audio clock as the backing, corrected for the phone's own delay; a Line up slider (remembered per phone, or measured with four clicks) fixes what is left.
• Play with the accompaniment. The teacher records or uploads the real piano part of a piece and can set how many times this week. The pupil plays along with it in headphones at 75%, 90% or full speed; the pitch stays the same (WSOLA time-stretch on the device).
• Kept tracks (up to five a week; a teacher's star keeps one past that) go in the week as the raw recording plus a small recipe (style, key, chords, tempo, offset, volume), so the mix is rebuilt whenever it plays. They live in the private bucket, or IndexedDB on the device in demo and local mode. The teacher plays them, stars them and sends one line back; the share card says how many were made. Download renders a WAV on the device: direct for 13 and over, behind the account email for younger pupils. Making music never adds practice minutes.
• Instruments are bundled samples (Salamander Grand Piano; cello, violin and acoustic guitar from tonejs-instruments, both CC BY 3.0), 690 KB in all, fetched on first use and cached by the service worker; pad, drums and clicks are synthesised. Account deletion now also removes the person's files in the private bucket.

What's in v0.10 (23 September 2026)

Needs supabase/v0.10-partners-reviews-auditions.sql run once in the Supabase SQL editor; until then partners and reviews stay hidden (the teacher sees a note). Everything else works without it.

• Practice partners. The teacher pairs two pupils. Each sees the other's first name, minutes today, and, when both are 13 or over, "practising now". Match your partner's minutes on the same day (within a tenth, with the sound check agreeing) and you both get double points; three matched days in a row raise the pair's challenge by ten minutes, up to the grade limit. No messaging.
• Performance review and the end-of-term performance class. The teacher opens one for everyone or a group. Pupils pick what they liked most and what could be better from ten categories, one point per classmate reviewed; each performer sees their tally once the teacher releases it. The live class is not recorded.
• Audition prep. Switched on per pupil with who it is for, the excerpts, the panel and the date. Ten minutes of preparation in the teacher's voice (context, breathing, body, seeing the room, hearing the opening, "As soon as you're ready, please begin"), then one take (audio for everyone, video for 18 and over) into private storage, then the pupil's gut feeling 1 to 5. The teacher rates the same take and writes feedback; both see how often they agreed within a point.
• Habits. A weekly promise (how many days), a when-and-where plan, a fresh start after a few days away, personal bests against your own past weeks only, and milestones at 1, 5, 10, 25, 50, 100, 200 and 365 sessions.

What's in v0.9 (23 September 2026)

• Groups. A teacher puts pupils in any groups (a school, a year, a section), several per pupil, in each profile. Messages, group weeks and breaks can go to a whole group. Pupils in no group are flagged on the teacher's page ("Not in a group. Check whether they should be"), with Fine on their own to clear the flag.
• The sound check. During a session the phone counts the seconds an instrument is sounding, and the teacher sees "heard playing 18 of 20 min" for each day. Nothing is recorded or sent; the teacher's spoken captions are not counted. No microphone, and the day says "not checked".
• Grade limits. Grades 1 to 2 up to 30 minutes a day, 3 to 4 up to 45, 5 and above up to 60. Profiles on the old bands keep them until the teacher picks a new one.
• Your own target. A pupil can raise their daily target in Goal; every change, by pupil or teacher, is logged on the teacher's pupil page.
• The break. Over half term, a holiday, or any gap of two weeks or more between lessons, every practice day earns two tokens, and practising on most days wins a bigger reward the teacher names. The pupil's trail shows the break, the teacher's last "what you did well" line, and a Keep going over the break clock once the week's sessions are done.

What's in v0.8 (19 September 2026)

• The week's passage. On the pupil page the teacher records the few bars that matter this week, up to a minute, once, the way she wants them to sound. The pupil's trail gets a card with her clip (Play, Play slowly at 60% with the pitch kept) and Record mine: the same bars, thirty seconds at most. On the phone, Stuckato turns both clips into note lists (pitch tracking in the browser, passage.js, no server), lines them up, and says "Stuckato thinks 13 of 14 notes matched Melisande's. Have a listen at 0:05." Each spot is a chip: Hers, Loop hers (three times), Mine. Send it and the take goes to the teacher.
• Triage for the teacher's ears. The pupil page shows each day's take with its spots and Yours / Theirs buttons that play just those seconds, so she hears the twenty seconds that matter instead of a five-minute play-through. Heard it and Ask them work as for the sentence. The week's trend (Monday three notes off, Thursday one) is on both sides, on the parent card ("The passage: 13 of 14 notes matched Melisande's on Friday, up from 11 on Thursday"), in the lesson boxes ("The passage: still differs at 0:05 on Friday's take") and in the pilot CSV (passage_takes, passage_first_off, passage_last_off).
• What it does not do, on purpose. It never says "wrong": phone microphones, vibrato, open-string ring and double stops produce the odd false spot, so every spot is a place to listen, and the wording says so ("Stuckato hears roughly. Melisande decides."). It hears one note at a time: piano, guitar and harp get a note that chords will give rough spots. There is no real-time green-and-red, no score, no photo of the music, no rhythm verdict. No token for a take; tokens still come with the sentence.
• Repeated notes are split on the loudness dip (a bow change, a re-struck key), so Twinkle comes out note for note. Fourteen unit tests in test/ (npm test) cover the pitch tracker, note segmentation, alignment and comparison on synthesised tones; the real test is a cello through a phone.
• Demo view: ?demo=passage.

What's in v0.7 (16 September 2026)

• The sentence. After every session the pupil writes (or dictates) what they worked on and what changed. "Done for today" stays off until there is a real sentence, and the day's token, coin and streak arrive with the sentence, not the tick. Close the app without writing it and Today shows "Day N isn't finished" until you do.
• The teacher reads it. On the pupil page, each day shows the sentence with three taps: Sounds right (confirms), Ask them (a one-line question that lands on the pupil's Today screen), Doesn't add up (takes the token back and greys the day). The pupil list shows "finished today 18:42", "sentence missing" and "play-through to hear".
• The fermata. When the last step's clock reaches zero the screen holds on a fermata: Pause. Take a break. Tap or wait, then the Done screen.
• Tell me when they finish. A per-pupil switch on the pupil page; when on, the teacher gets an email the moment the sentence is saved (api/notify.js, Resend; silent if email is not configured).
• The play-through. The day before the lesson (or once every day is done) Today asks for one recording of the piece, all the way through, up to five minutes. It uploads to the audio bucket under <studio>/recordings/<pupil>/<week>; the teacher gets a player, Heard it, and a one-line reply that goes to the pupil now and is pre-filled as next week's "What you did well". The week's two bonus tokens wait for it. The bucket is public-read, so anyone with the exact URL can play a recording: fine for the pilot, move recordings to a private bucket before it grows.
• The light on the goal. A dot and a word next to the goal, on Today, the Goal tab and the teacher's list: green On track (80%+ of the goal-weeks so far had practice in them), amber Slipping (50 to 79%), red Talk about the date (under 50%), dropped one level when it is day five or later with fewer than two days done. The one place colour is used for something other than a flag.
• Name: Stuckato (stuck + staccato). Mark: the S with a staccato dot above it.
• Demo views: ?demo=done, ?demo=fermata, ?demo=pupilpage, ?demo=pupil2 (the pupil whose play-through is due).

What's in v0.3 (14 September 2026)

• Group mode for choirs and orchestras: a studio can be an ensemble. Members set their part (alto, second violin); the conductor opens the Group tab, picks everyone or particular parts, writes one rehearsal note, reviews one preview, and publishes a week to every member. The sessions are written for "your part": notes and rhythms slowly, entries counted, words from memory, listening with the score. The conductor's cloned voice is synthesised once and shared. Add a task to everyone, and book a rehearsal for everyone, from the same screen
• Tasks during the week: a teacher who thinks of something on Wednesday adds it to a pupil's week without rewriting it. It appears on the pupil's Today screen under "New from [teacher]" and in their Journey checklist; the pupil ticks it off
• New name, new mark (then Melodigo): a quaver whose flag is the finish flag as the i

What's in v0.5 (15 September 2026, evening)

• A session every day. Seven daily sessions by default (the teacher can set three to seven), one lighter day in the middle. The week is drawn as notes on a stave: filled notes are days done, the amber ring is today
• Tick what you worked on. Every week comes with a work list (scale, passage, technique, piece). After each session, or after practising without the timer ("I practised on my own"), the pupil ticks what they did and can add their own. The teacher's pupil page shows worked on most this week, and last week's tally goes into the planner so neglected items get their turn
• The interface, redone for a nine-year-old and a teacher of any age. One bold sans typeface throughout, black on beige (the logo's colours, one theme), every fact in its own box or chip (date, day 3 of 7, minutes set by the teacher), the teacher's line as a speech bubble, bigger buttons and labels, nothing crammed
• Today, in order. The week on the stave with any news from the teacher inside it, the teacher's line for the week, last time, today's session, the two buttons (start the guided session, or "I practised on my own"), then the streak and how many points to the reward. Everything in the same size except the two buttons
• The teacher's side is one page too. Left: the code to give pupils, then the pupils. Right: Send a message (everyone, parts, or chosen pupils; it lands as news on their trail) and Whole group (one week for everyone, opens the group form). No tabs. Flag counts and flags are in red
• The parent card is three boxes: the dates, the pupil's week (days done, minutes practised, points earned), and the teacher's feedback from the last lesson with "For next lesson" underneath. When the teacher has set an exam or concert date, a fourth box draws the goal as the end of a piece: one note a week from the first week to the date, filled when practised, a ring on this week, bar lines every four weeks and the double bar line on the day; then weeks practised and weeks complete
• One screen, the trail. The pupil's side has no tabs. Top to bottom: the lesson box (what you did well, what to work on, news), the seven days as a winding path with today's session as a card on it, the next lesson as a black box, show-the-teacher, ask-the-teacher (red-edged), tokens, the last four weeks, the road to the goal with its stages, and two buttons: set or change the goal, share the card. A black Start today bar is pinned at the bottom so the session is always one tap, wherever you have scrolled
• The map. The seven days wind from the last lesson to a black "Next lesson with Melisande" box: a note a day (filled when done, ring on today), a +1 token beside each day and +2 at the end. Below the map, in order: "At the lesson: show Melisande" (the checklist, where the path ends) and "At the lesson: ask Melisande" (the flags, in a red-edged box), then the tokens
• Stages to the goal are the teacher's, or absent. The trail shows the weeks to the date as a stave; named stages (Foundations, Pieces, Polish…) appear only if the teacher types them into the pupil's profile. The app does not invent a syllabus
• The month and the goal. Today shows one chip with the goal and weeks to go, when there is one. The trail and the teacher's pupil page stack the last five weeks as small staves, most recent first, with the goal date under them. The road on the trail draws the same stave above the stages
• How it felt: Easy, Fine, Hard. One axis, three taps. Hard asks one more thing, "which bit?", from the work list; that answer goes to the teacher as a flag for the next lesson. Easy and Fine ask nothing more
• The planner does not teach. The only technical content in a session is what the teacher wrote, restated in her words and attributed; where the note says nothing for a step, the caption is about how to practise (slowly, once through, stop), not how to play. The app never claims to judge the pupil: where it listens (the week's passage), it points at the bars that differ from the teacher's playing, and the pupil and the teacher judge
• This week, from the teacher on Today shows the work for the week (her "know by next lesson" list) first, then her one line

Later

• A conductor's side of its own (next to pupil, teacher and parent's view): today a choir or orchestra is a studio in group mode on the teacher's side

What's in v0.4 (15 September 2026)

• A named reward. The teacher writes what six tokens earns ("a hot chocolate after Thursday's lesson"); the pupil sees it on their Journey, and the teacher marks it given
• The teacher sets the practice time. Level is a dropdown (beginner, grades 1 to 3, 4 to 6, 7 to 8, returning adult, advanced) and each level suggests minutes a day (20, 25, 40, 60, 25, 75); the teacher can override it per pupil, up to 120. The sessions are written to that length and the pupil's Today screen says who set it
• The morning message. On any morning a session is due, the pupil gets one note from the teacher: what they did last time and how they said it felt, what is on today and how long. Never twice a day, nothing once the week is done. Delivered as a phone notification (web push, the app added to the Home Screen) or by email; the pupil chooses under Goal and can send themselves today's message to check it. A daily Vercel cron (/api/reminders, 06:30 UTC) does the sending and logs every send against the pupil, so completion within the day can be measured
• Installable: manifest, icons and a service worker, so Stuckato sits on the Home Screen like an app

What was in v0.2

• Email sign-in (no password); teachers create a studio and get a six-character code; pupils join with it
• Teacher: pupils list with this week's progress and flags; per-pupil profile (instrument, level, goal, sessions a week, minutes); lesson note → generated week → preview → publish
• Pupil: Today (next session, streak, week dots), a session runner with a progress ring, captions, optional read-aloud (browser speech), pause/skip/stop, and "how did it feel"; Journey (path from lesson to lesson, checklist, flags, tokens); Goal (date, weeks to go, road phases)
• Tokens: one per session, two more for a full week; six is a small reward the teacher marks as given
• See how it works: a demo with three pupils and a week already set, switchable between the pupil's side, the teacher's side and the parent's view, no sign-in
• The teacher's voice: on first use the teacher reads a thirty-second passage with a consent box ticked; Stuckato clones the voice (ElevenLabs) and every caption in every published week is spoken in it. Only text the teacher has previewed and published is ever spoken; the teacher can re-record or delete the clone at any time, and deleting it removes it from ElevenLabs too. Pupils are told it's generated
• Dictated notes: every note field has a Dictate button. Browser speech recognition where it exists (Chrome, Safari), server transcription as the fallback
• Share card: the pupil turns their week into an image (sessions, minutes, streak, checklist, the teacher's line) and shares it with a parent or anyone they choose, from their own phone. Nothing is shared unless the pupil sends it; nothing else about them is in it
• Works on this device with no account, so anyone can try the whole loop alone (you play both sides)

Nothing scores you. Where the app listens (v0.8's passage), it compares you to your teacher and hands her the spots. That's the argument, not an omission.

Accounts, children and consent

Two kinds of account: teacher and pupil. There is no parent login. A young pupil's account is set up and held by a parent with the parent's own email (the onboarding says so, for under-13s), so the adult controls it, and the pupil decides what to share by sending the card. No third role means no extra personal data, no account linking, and nothing a stranger could reach: pupils are visible only to the teacher whose code they joined with. A pupil's document holds a name, an instrument, a level, a goal, the weeks, the flags and the feelings, and nothing else.

Stack

• index.html: the whole app, no build step, one Google Font (Plus Jakarta Sans)
• api/plan.js: a Vercel function. Takes the teacher's note, the pupil's profile and last week's tally (or a conductor's rehearsal note and the parts it is for), calls Claude (claude-opus-5, structured JSON output, effort medium, server-side refusal fallbacks) and returns the week: one session per day with steps, minutes and captions, a work list, a checklist, one line of encouragement
• api/voice.js: creates the teacher's cloned voice from the recorded sample (ElevenLabs), or deletes it. Teacher only, verified server-side against Supabase
• api/speak.js: turns one caption into audio in the studio's voice and stores it in the melodigo-audio bucket under the studio's folder, using the teacher's own session so storage policies apply
• api/transcribe.js: spoken notes to text (ElevenLabs Scribe) for browsers without built-in dictation
• api/reminders.js: the morning message. GET from the cron (Authorization: Bearer CRON_SECRET) sends to every pupil due; POST from a signed-in pupil sends their own message now. Uses the Supabase service-role key server-side to read every pupil row
• passage.js: the week's passage, pure functions with no DOM: resample to 16 kHz, McLeod pitch tracking (normalised square difference), frames to notes with repeated-note splitting, Needleman-Wunsch alignment of the two note lists, and the comparison that yields the spots. Runs in the browser on the recording device; imported under Node by the tests
• backing.js: backing tracks, pure functions with no DOM: key finding (Krumhansl-Kessler), chords that follow the player (a semi-Markov Viterbi over note onsets), looped progressions, voicing, the arrangement for each style, lineUp (delay by envelope cross-correlation), WSOLA time-stretch and the WAV encoder. Imported under Node by the tests
• backing-audio.js: the sound: sample playback, synthesised pad and drums, preview, the offline render for downloads, recording in the same clock as the backing, and the phone-delay estimate. samples/ holds the instruments
• sw.js, manifest.webmanifest, icon-192.png, icon-512.png: the installable app and its notifications
• api/config.js: public Supabase config for the page, plus which features are configured
• supabase/schema.sql: studios, members, one JSON document per pupil that the pupil and their teacher can both read and write, row-level security, the RPCs. Every database object is prefixed practicigo_ (renamed from melodigo_ on 16 September 2026 by supabase/migrate-practicigo.sql; the audio bucket keeps its id melodigo-audio because stored caption and recording URLs embed it).
• logo.svg (lockup with slogan), wordmark.svg, mark.svg (the sforzando s), icon-tile.svg: outlines, no font needed

Deploying

Vercel serves index.html as static and api/* as Node functions. Environment variables:

Name	Required	What
ANTHROPIC_API_KEY	yes	Writes the weeks
SUPABASE_URL, SUPABASE_ANON_KEY	for accounts	Project Settings → API. The anon key is public by design
ELEVENLABS_API_KEY	for the voice	Voice cloning, spoken captions, and transcription fallback
SUPABASE_SERVICE_ROLE_KEY	for the morning message	Server-only; lets the cron read every pupil. Never sent to the page
VAPID_PUBLIC_KEY, VAPID_PRIVATE_KEY, VAPID_SUBJECT	for notifications	Generate once with npx web-push generate-vapid-keys
CRON_SECRET	for the cron	Vercel sends it as the bearer token on the scheduled call
RESEND_API_KEY, REMINDER_FROM	for email messages	Resend account with a verified domain; falls back to push only when unset

Supabase: run supabase/schema.sql in the SQL editor once; under Authentication → URL Configuration add the live URL to Redirect URLs. The built-in email sender is rate-limited, so add custom SMTP (Resend) before a real cohort.

Running locally

Open index.html in a browser and choose "Try it on this device". Accounts and the generated weeks need the deployed functions; the file version writes a plain placeholder week so the loop can still be walked through.

npm test runs the unit tests for passage.js and backing.js (Node 22 or later, no dependencies).

Roadmap

1. Pilot with twenty pupils and one ensemble; measure who is still practising in week four
2. The week's passage against a MusicXML file when the teacher has no time to record; a photo of the score later, with a confirm step, once the recorded version has proved itself
3. Custom SMTP for sign-in emails; a daily cap on generation per studio; the morning message as a voice note in the teacher's voice, and over WhatsApp
4. Piano and singing programmes; returning-adult track; sectionals (one note per part) for larger ensembles
5. Studio and ensemble licences for schools, youth orchestras, choirs and music hubs

The name

Stuckato (from 17 September 2026; Stuckato, Melodigo, Sostenuto and Rosin before that): stuck and staccato. Practice in short, detached bursts, short bursts, real progress, so nobody stays stuck between lessons. Database objects keep the practicigo_ prefix from the previous name; renaming them would need another migration and gains nothing.

Founders

Melisande Yavuz (Royal Academy of Music Fellow, violinist and teacher) and Emre Yavuz (PhD computational neuroscience, UCL). September 2026.