Piano synth · ling-3.1-flash

Let me start by examining the current directory and the provided tone.min.js file.

The tone.min.js is present. Let me check the Tone version to know what API to use.

Tone.js 14.8.49. Good, that's the classic API (Tone.Synth, Tone.PolySynth, etc.).

Requirements:
1. One chromatic octave C4 through C5 (13 notes: C4, C#4, D4, D#4, E4, F4, F#4, G4, G#4, A4, A#4, B4, C5)
2. Correctly placed black/white keys with visible note labels
3. Computer keys A W S E D F T G Y H U J K map in order to those 13 notes
   - A→C4, W→C#4, S→D4, E→D#4, D→E4, F→F4, T→F#4, G→G4, Y→G#4, H→A4, U→A#4, J→B4, K→C5
4. Pressing screen key or computer key starts note; releasing starts envelope release phase
5. Synthesized voice with ADSR envelope, at least 3 simultaneous notes (PolySynth with 4+ voices, or Monophonic synth per note... PolySynth supports polyphony)
6. Highlight keys while held
7. Prevent keyboard auto-repeat duplicates (check e.repeat)
8. Release held voices when pointer released outside key or window loses focus
9. Activate audio through user gesture (Tone.start() on first interaction)
10. Display computer-key mapping

Implementation plan:
- Use Tone.PolySynth with Tone.Synth voice, ADSR envelope configured. PolySynth handles polyphony (voices count = number of notes by default, maxVoices option). Set maxVoices to at least 4 (default is 32 or unlimited). Actually Tone.PolySynth has maxVoices option; default is 32 in Tone.js? Let me check: `new Tone.PolySynth(Tone.Synth, { maxVoices: 8 })`. Actually PolySynth constructor: `new Tone.PolySynth(voice, options)` where options can include maxVoices. In Tone 14, PolySynth extends PolySynth... The options object passed as second argument is passed to voice constructors plus maxVoices. Yes.

- Key tracking: Map both keyboard events and pointer events to a set of active notes. For pointer, use pointerdown on key element, then listen pointerup and pointercancel on window (or setPointerCapture). To handle "pointer released outside a key", the simplest robust approach: on pointerdown on a key, capture the pointer (element.setPointerCapture) so the key gets pointerup even if pointer leaves; also add window pointerup handler that releases all notes for that pointer. Also track activePointers: Map pointerId -> note.

- On blur: release all.

- Prevent auto-repeat: in keydown, if (e.repeat) return.

- Also prevent default for mapped keys to avoid scrolling (e.g., space not used, but fine).

- Highlight: add class "active" to key element. For computer-key display: show mapping label on each key (e.g., "A", "W", etc. on each key).

- Note labels: visible note labels (C4, C#4...) on keys. Maybe show note name on white keys at bottom and computer key at top.

- Audio activation: On first pointerdown/keydown anywhere, call Tone.start(). Show status "Audio: on" after activation.

- ADSR: attack 0.01... Let's configure: attack: 0.05, decay: 0.2, sustain: 0.4, release: 0.5. Maybe slightly musical: attack 0.02, decay 0.3, sustain 0.5, release 1.0.

- Visual: nice piano look — white keys with black keys overlaying. Layout: white keys in a flex row, black keys absolutely positioned between them.

Structure for piano: container relative; white keys as flex children; black keys positioned absolutely with left percentages. Standard: black keys sit at boundaries. For octave C4-C5: white keys: C D E F G A B (7). Black keys: C#, D#, F#, G#, A# (5).

Black key positions: each white key width = 100%/7. Black keys centered on the right edge of white keys C, D, (skip E), F, G, A. So left = (i + 1) * whiteWidth - blackWidth/2 where i = white index (0 for C, 1 for D, 3 for F, 4 for G, 5 for A).

I'll build the keys in JS from a data array:
```js
const NOTES = [
  { note: "C4", type: "white", key: "A" },
  { note: "C#4", type: "black", key: "W" },
  { note: "D4", type: "white", key: "S" },
  { note: "D#4", type: "black", key: "E" },
  { note: "E4", type: "white", key: "D" },
  { note: "F4", type: "white", key: "F" },
  { note: "F#4", type: "black", key: "T" },
  { note: "G4", type: "white", key: "G" },
  { note: "G#4", type: "black", key: "Y" },
  { note: "A4", type: "white", key: "H" },
  { note: "A#4", type: "black", key: "U" },
  { note: "B4", type: "white", key: "J" },
  { note: "C5", type: "white", key: "K" },
];
```

Note ordering matches A W S E D F T G Y H U J K. 

Rendering: white keys container flex; black keys absolutely positioned. Compute black key positions after layout — or compute with percentages: white width = 100/7 ≈ 14.2857%. Black key width = ~60% of white width. Position black key centered on boundary between white i and i+1: left = (i+1)*(100/7)% - blackWidth%/2.

Black keys indices (white index before boundary): C# at boundary after C (i=0), D# after D (i=1), F# after F (i=3), G# after G (i=4), A# after A (i=5).

Labels: each white key shows computer key (top, small) and note name (bottom). Black key shows computer key (top) and maybe note name (middle/bottom in lighter color).

Also display a mapping legend: a row showing all 13 mappings, maybe a bar under the piano listing "A → C4, W → C#4, ...". The requirement says "Display the computer-key mapping" — labels on keys themselves plus a legend would be good.

Pointer handling:
- pointerdown on key: if e.button !== 0 for mouse? Pointer events: check e.isPrimary or allow multi-touch. Use pointerId tracking.
- keyEl.setPointerCapture(e.pointerId) so we get pointerup even off-element. Add pointerup and pointercancel listeners on the key element; with capture they'll fire on the key. Also window blur → release all.
- On pointerup: release note, remove highlight, delete from active map.

For simultaneous notes: PolySynth with maxVoices: 16. Also handle same note triggered by both keyboard and pointer simultaneously: track count per note? Keep a set of sources. Simplest: track active notes in a Map note -> Set of source ids ("kb", "ptr-1", ...). When trigger, add source; when released, remove source; only call release when set becomes empty. That handles overlapping pointer/keyboard on the same note.

But PolySynth: if note already sounding and we trigger again, it re-triggers that voice (triggerAttack re-triggers). Fine.

Also keydown for mapped key: e.code or e.key? Use e.key.toUpperCase() to match "A" etc. But e.key depends on layout; use e.code ("KeyA", "KeyW"...) which is layout-independent (physical key). The mapping says "computer keys A W S E D F...", physical key codes KeyA etc. I'll use e.code for robustness and also show the letter. Use code like "KeyA" → letter. Map code → note.

Also prevent default on keydown for mapped keys to avoid page scroll etc.

Audio start: async Tone.start(). Wrap: on first user gesture (pointerdown or keydown on document), call ensureAudio: if (!started) { await Tone.start(); started = true; update status }. Tone.start() returns promise.

Envelope: Tone.PolySynth(Tone.Synth, { envelope: { attack, decay, sustain, release }, oscillator: { type: "triangle" } }). Maybe "fatsawtooth" for richness. Keep simple: oscillator type "triangle" or "square"? Let's do "fatsawtooth" with count 2? Keep to "triangle" for clean synth. Actually a pleasant default: "sine"? Piano-ish: triangle. I'll use "fatsawtooth" with spread small? Simpler: triangle.

Also add a master volume? Not necessary. Maybe add a lowpass filter? Keep simple.

Also show a status line: "Click a key or press a computer key to enable audio" → after activation "Audio ready".

Also add a "release all" on visibilitychange hidden? blur covers window focus loss. Add window blur handler.

Also note: releasing the envelope — PolySynth.triggerRelease(note). Requirement: "releasing it starts the envelope's release phase" — yes triggerRelease.

Keyboard: on keydown (not repeat), start; keyup, release.

Also when pointer is released outside a key: pointer capture ensures key receives pointerup. Also add a safety: window pointerup releases all notes associated with that pointerId.

Console after audio activation: log "AudioContext started". Also maybe log note on/off — requirement says "Check ... the console after audio activation". So console.log on activation. Maybe log each note trigger/release too — helpful for verification.

Visual polish: dark theme page, piano with realistic shading, highlight gradient. Black keys highlighted with different glow.

Let me also add velocity? Not needed.

Edge: keydown when audio not yet started — ensureAudio is async; Tone.start() must be called within gesture; triggering notes before start may warn "AudioContext not started". To be safe, on first gesture call Tone.start(), and queue? Simple approach: in note-on handler, call ensureAudio() (fires Tone.start() in gesture), then trigger note. Tone.js handles triggering after start fine (the context resumes asynchronously; the note attack still plays once running, since Tone started scheduling... triggerAttack schedules at Tone.now() + small offset which will be after resume. Should be fine in practice.)

Let me write the HTML now.

Layout:
- Header: title "Piano — C4 to C5", subtitle with instructions.
- Piano container (~700px wide, 260px tall), responsive.
- Legend row: 13 chips "A → C4" etc.
- Status bar: audio status + polyphony note.

CSS:
- White keys: flex:1, background linear-gradient white, border-radius bottom, box-shadow, cursor pointer, user-select none.
- Black keys: absolute, height ~62%, width computed via CSS var? Width: use calc. Black key width = 6% of container (approx 0.6 * 14.28 = 8.57%... hmm white width is 14.28%, black typically ~60% of that = 8.57%). Let's set black width to 8% and left calc via JS inline style percentages computed precisely. I'll compute positions in JS with percentages: whiteW = 100/7; blackW = whiteW*0.62; left = (i+1)*whiteW - blackW/2. Set style.left and style.width directly. 

Highlight classes:
- .white.active: background gradient yellow/amber, box-shadow inset.
- .black.active: background gradient lighter.

Labels: white key: computer key badge at top (small dark pill), note name at bottom. Black key: key badge top (white text), note name below in light gray, smaller.

Font: system fonts.

JS details:

```js
const NOTE_ORDER = [...];
const codeToNote = {}; // 'KeyA' -> 'C4'
const noteToCode = {};
```

State: activeSources = Map(note -> Set(source)).

```js
function noteOn(note, source) {
  let set = activeSources.get(note);
  if (!set) { set = new Set(); activeSources.set(note, set); }
  set.add(source);
  if (set.size === 1) {
    synth.triggerAttack(note);
    setActiveVisual(note, true);
    console.log('note on', note);
  }
}
function noteOff(note, source) {
  const set = activeSources.get(note);
  if (!set || !set.has(source)) return;
  set.delete(source);
  if (set.size === 0) {
    activeSources.delete(note);
    synth.triggerRelease(note);
    setActiveVisual(note, false);
    console.log('note off', note);
  }
}
function releaseAll() {
  for (const note of [...activeSources.keys()]) noteOff(note, ...) // need to clear all
}
```

releaseAll: iterate and triggerRelease for each remaining.

Pointer handlers per key element:

```js
key.addEventListener('pointerdown', (e) => {
  e.preventDefault();
  ensureAudio();
  key.setPointerCapture(e.pointerId);
  noteOn(note, 'p' + e.pointerId);
});
key.addEventListener('pointerup', (e) => noteOff(note, 'p' + e.pointerId));
key.addEventListener('pointercancel', (e) => noteOff(note, 'p' + e.pointerId));
key.addEventListener('lostpointercapture', ...) // maybe not needed
```

With pointer capture, pointerup fires on key even if released outside. Also window blur releases all. Also add window pointerup as extra safety releasing any pointer ids still active.

Keyboard:

```js
window.addEventListener('keydown', (e) => {
  if (e.repeat) return;
  const note = codeToNote[e.code];
  if (!note) return;
  e.preventDefault();
  ensureAudio();
  noteOn(note, 'kb');
});
window.addEventListener('keyup', (e) => {
  const note = codeToNote[e.code];
  if (!note) return;
  e.preventDefault();
  noteOff(note, 'kb');
});
window.addEventListener('blur', releaseAll);
document.addEventListener('visibilitychange', () => { if (document.hidden) releaseAll(); });
```

Also pointerup on window for safety:

```js
window.addEventListener('pointerup', (e) => {
  // release any source 'p'+e.pointerId still active (safety)
  for (const [note, set] of [...activeSources]) {
    const src = 'p'+e.pointerId;
    if (set.has(src)) noteOff(note, src);
  }
});
```

Careful: window pointerup fires after key's pointerup (capture retargets to key, and bubbles to window). noteOff second call is no-op. Fine.

ensureAudio:

```js
let audioStarted = false;
async function ensureAudio() {
  if (audioStarted) return;
  audioStarted = true; // set immediately to avoid double calls
  try {
    await Tone.start();
    statusEl.textContent = 'Audio ready — click or press keys';
    console.log('Tone.js audio activated', Tone.now());
  } catch (err) {
    audioStarted = false;
    console.error('Audio activation failed', err);
  }
}
```

Hmm, setting audioStarted=true before resolution: if Tone.start() fails, retry on next gesture. But Tone.start resolves quickly. Fine. Actually better: keep a promise:

```js
let audioPromise = null;
function ensureAudio() {
  if (!audioPromise) {
    audioPromise = Tone.start().then(() => {...}).catch(err => { audioPromise = null; ... });
  }
  return audioPromise;
}
```

Also maybe add "Audio will activate on your first click/keypress" initially.

Also first-visit: maybe add a one-time overlay "Click to enable sound"? Not required — "Activate audio through a user gesture" is satisfied by activating on first pointer/key event. But a nicer UX: a small "Enable sound" button that also calls ensureAudio. The status bar with instructions is fine.

Polyphony: `new Tone.PolySynth(Tone.Synth, { maxVoices: 16, envelope: {...}, oscillator: { type: 'triangle' } }).toDestination();` Wait — PolySynth options: the second arg options are passed to the voices plus `maxVoices` recognized by PolySynth. In Tone.js 14, `new Tone.PolySynth(Tone.Synth, { envelope: {...} })` works — PolySynth's constructor options extend Voice options with maxVoices. Yes.

Volume: maybe synth.volume.value = -6? Not necessary.

Also set `synth.release`? No.

Let me also verify ADSR values are applied — log synth envelope in console after creation for verification.

Console verification: after clicking a key, expect "Tone.js audio activated", "note on C4", "note off C4".

Now write the file. I'll make the piano responsive: container width min(92vw, 760px), height ~ clamp(220px, 40vh, 300px).

Also the requirement: "Display one chromatic octave from C4 through C5" — 13 keys. Done.

Legend: chips showing `A→C4`, etc. Also a line explaining: "Computer keys: A W S E D F T G Y H U J K".

Let me also make the keys focusable? Not needed.

One more subtlety: keydown preventDefault for 'KeyA' etc. only when mapped — done.

Also avoid context menu on long press? Not needed for desktop. Add `touch-action: none` on keys to prevent scrolling/zoom on touch. Good.

Write the code.

Also, for the check "press-and-release highlighting" — visible .active class; also maybe a "currently playing" indicator listing active notes in status bar — nice touch, helps verification: "Playing: C4 E4". Update on noteOn/noteOff. 

Now write index.html.

Height of black keys: 62%. z-index: black keys above white. Position: absolute top 0.

White key label layout: 
- .key-badge: top area, small rounded pill showing computer key letter (e.g., "A"), background rgba(0,0,0,.08) on white; on black keys, rgba(255,255,255,.15) with white text.
- .note-label: bottom, font-weight 600, color #333 / for black keys #ddd, font-size smaller.

Also middle C label maybe emphasized.

Container: position relative; display flex for white keys; black keys absolutely positioned within.

HTML skeleton:

```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Piano — C4–C5 · Tone.js</title>
<style>...</style>
</head>
<body>
<main class="app">
  <header>
    <h1>🎹 Mini Piano</h1>
    <p class="sub">Chromatic octave C4–C5 · synthesized with Tone.js (ADSR)</p>
  </header>

  <section class="statusbar">
    <span id="audioStatus" class="status audio">🔇 Audio: press any key or click to activate</span>
    <span id="playingStatus" class="status playing">Playing: —</span>
  </section>

  <section class="piano" id="piano" aria-label="Piano keyboard C4 to C5"></section>

  <section class="legend" id="legend"></section>
  <p class="hint">Mouse / touch: press &amp; hold keys · Keyboard: <kbd>A</kbd><kbd>W</kbd>... in order · Polyphonic — hold multiple keys at once</p>
</main>
<script src="tone.min.js"></script>
<script> ... </script>
</body>
</html>
```

Build piano and legend in JS.

CSS details:

```css
:root {
  --white-key-w: calc(100% / 7);
}
body { margin:0; min-height:100vh; background: radial-gradient(...); font-family: system-ui,...; color:#e8eaf0; display:flex; ... }
.app { width:min(94vw, 820px); margin:auto; text-align:center; }
.piano { position:relative; display:flex; height:clamp(220px, 42vh, 320px); border-radius: 0 0 12px 12px; padding: 0 6px 6px; background: #1c1f26; box-shadow: ...; }
```

Hmm, if piano has padding-bottom, white keys' heights need to account. Simpler: white keys full height; container has outer frame styling. Let's do: .piano { background:#111; border-radius:12px; padding:10px 8px 8px; } and inner .keyboard { position:relative; display:flex; height: ...; } Actually let me nest: .piano (frame) > .keys (relative flex row). White keys are children of .keys (flex), black keys absolute within .keys.

White key:
```css
.white {
  flex: 1 1 0;
  background: linear-gradient(to bottom, #fdfdfd 0%, #f4f4f6 85%, #d9dbe1 100%);
  border: 1px solid #b9bcc6;
  border-top: none;
  border-radius: 0 0 7px 7px;
  box-shadow: inset -2px -4px 6px rgba(0,0,0,.08);
  position: relative;
  cursor: pointer;
  touch-action: none;
  user-select: none;
  display:flex; flex-direction:column; justify-content: space-between; align-items:center;
  padding: 10px 2px 8px;
}
.white.active {
  background: linear-gradient(to bottom, #ffe9a8, #ffd35c 70%, #f5b81d);
  box-shadow: inset 0 0 12px rgba(255,160,0,.55);
  transform: translateY(1px);
}
```

Black key:
```css
.black {
  position:absolute; top:0; height:62%;
  background: linear-gradient(to bottom, #3a3d45, #0c0d10 90%);
  border-radius: 0 0 6px 6px;
  z-index: 2;
  box-shadow: 0 4px 6px rgba(0,0,0,.5), inset 0 -4px 6px rgba(255,255,255,.06);
  ...
}
.black.active {
  background: linear-gradient(to bottom, #ffd35c, #e89b0c);
  color: #231a00;
}
```

Labels inside black keys: badge and note label with colors adjusted when active. Use CSS var for label color: .black { --label:#cfd2da; --badge-bg: rgba(255,255,255,.14); } .black.active { --label:#3a2703; --badge-bg: rgba(0,0,0,.15); } and .white { --label:#3c3f47; --badge-bg: rgba(0,0,0,.08);} etc.

Badge style: 
```css
.key-badge { font-size: 12px; font-weight:700; padding: 2px 7px; border-radius: 999px; background: var(--badge-bg); color: var(--label); letter-spacing:.5px; }
.note-label { font-size: 13px; font-weight: 700; color: var(--label); }
.white .note-label { font-size: 14px; }
```

Legend chips:
```css
.legend { display:flex; flex-wrap:wrap; gap:6px; justify-content:center; margin-top:18px; }
.chip { background:#242833; border:1px solid #333947; padding:5px 9px; border-radius:8px; font-size:12.5px; }
.chip b { color:#ffd35c; margin-right:4px; }
```

Hint with kbd styling.

JS: also highlight mapping chip when note active? Extra: chip gets .active class. Nice touch — update chips alongside keys.

Now the JS:

```js
const NOTES = [
  { note:"C4",  type:"white", key:"A", code:"KeyA", blackAfter:false },
  ...
];
```

For black keys I need the white-index boundary. I'll include `afterWhiteIndex` for black keys: C# after white 0 (C), D# after white 1 (D), F# after white 3 (F), G# after white 4 (G), A# after white 5 (A).

Render:

```js
const keysEl = document.getElementById('keys');
const whiteCount = NOTES.filter(n=>n.type==='white').length; // 7
const whiteW = 100 / whiteCount;
const blackW = whiteW * 0.62;
NOTES.forEach(n => {
  const el = document.createElement('div');
  el.className = 'key ' + n.type;
  el.dataset.note = n.note;
  el.setAttribute('role','button');
  ...
  if (n.type === 'black') {
    el.style.left = `calc(${(n.afterWhiteIndex+1)*whiteW}% - ${blackW/2}%)`;
    el.style.width = blackW + '%';
  }
  el.innerHTML = `<span class="key-badge">${n.key}</span><span class="note-label">${n.note}</span>`;
  keysEl.appendChild(el);
  keyEls[n.note] = el;
});
```

White keys order in DOM must be C D E F G A B — since NOTES includes blacks interleaved, append whites in order; blacks are absolute so DOM order among flex children doesn't matter as long as whites are the only flex items (blacks are absolute, removed from flow). Flex with absolute children works fine.

Legend build similar.

Everything else as planned. Let me also add `contextmenu` prevention on keys (right-click won't trigger anyway).

Potential pitfall: pointer capture + click: after pointerup with capture, a click event fires on key — harmless.

Another pitfall: on pointerdown we call e.preventDefault() which prevents focus; fine.

Mouse users pressing multiple keys simultaneously: pointer events support multi-touch; mouse only one pointer at a time — but keyboard allows simultaneous notes via multiple keys held. Good.

Now, verify with browser tools: click a white key, check highlight and console logs; press keyboard key 'A'; check blur release (hard to simulate blur—can dispatch event via console). Use browser tool actions: click at coordinates, key events. I'll load the page, screenshot, click key, type key, check console output. The browser tool has actions: reload, inspect, screenshot, motion, click, drag, key, type, scroll. "inspect" presumably shows DOM/console.

Let me write the file first.

One more consideration on `Tone.start()` in sandboxed environment: Tone.js requires an AudioContext; headless browser may allow it after gesture. Console log will confirm. If it fails, catch and show message.

Also note Tone.js 14.8 deprecation: `Tone.PolySynth(Tone.Synth, {...})` fine.

Volume: keep default.

Let me also add a subtle "envelope" info line: "ADSR — attack 0.02s · decay 0.25s · sustain 0.55 · release 0.9s".

Write it.

For keyboard mapping display: also show under title the sequence: "Keyboard: A W S E D F T G Y H U J K → C4 C♯4 D4 D♯4 E4 F4 F♯4 G4 G♯4 A4 A♯4 B4 C5". Use ♯ symbol? Labels on keys: use "C#4" plain to be safe. Legend chips: "A → C4" etc.

Time to write.

Also: prevent stuck notes if keyup missed due to blur — covered by blur handler.

Edge: e.code for keyboard — some browsers with certain layouts produce different e.code? e.code is physical position, reliable.

Also add `window.addEventListener('keyup')` even when repeat... keyup always fires once. Fine.

Write index.html now. Then run browser checks.

Now let me run it in the browser to verify. First, reload/inspect initial state.

The page loaded. The DOM shows all 13 keys with correct labels and mapping. There are a few issues:

1. The CSP blocked the worker creation (Tone.js tries to create a worker for its transport). This may be an artifact of the test harness sandboxing. The "worker-src 'none'" CSP error occurs at load — Tone.js creates a worker for the Transport when... Actually in Tone.js 14, the Transport uses a worker? The error appeared at load time even before user gesture. This might just be in this sandboxed browser environment; the synth itself may still work via setTimeout-based fallback. Tone.js 14.8 has a `ToneWorker`... Actually the error is about creating a worker from a blob URL. Tone.js uses a worker for the transport in newer versions. If blocked, Tone falls back? Let me check whether notes actually play.

2. My console log "Synth created — ADSR undefined maxVoices: undefined" — `synth.envelope` and `synth.maxVoices` aren't properties directly accessible. The envelope is on the voice; `synth.maxVoices` — PolySynth doesn't expose maxVoices as a property in 14.8? Actually it does have `maxVoices`... apparently undefined. Let me check via the browser console what properties exist. I can't directly run JS in the browser tool... The browser tool doesn't have an "eval" action. Hmm, actions: reload, inspect, screenshot, motion, click, drag, key, type, scroll. No eval. So console logs are my main window. I could add temporary console.log statements to introspect. Let me check Tone.js PolySynth API for 14.8.49:

- PolySynth constructor: `new Tone.PolySynth(voice, options)`. Options include `maxVoices`, `polyphony`? Let me check the source.

Also `synth.envelope` — PolySynth doesn't have an envelope property; the voice does. The log isn't critical but I want to confirm the envelope was actually applied. Let me grep tone.min.js for maxVoices and PolySynth to understand.

Also the AudioContext warnings at load: Tone.js tries to start the context at construction (it creates the context lazily? Actually Tone creates the context on instantiation of ToneContext and tries to resume). That's expected before a user gesture; our ensureAudio will resume on gesture.

Let me check the minified source for how PolySynth handles options and whether voices get the envelope, and what worker is created and whether it's critical.

Interesting — no "maxVoices" in tone.min.js. So in this version (14.8.49), the PolySynth option might be `polyphony`? Let me search for the PolySynth constructor options and how "polyphony count is no longer the first argument" is used, plus how the voices/ensemble are constructed. Also check for "voice" option names.

So in this version, PolySynth uses `maxPolyphony` option, not `maxVoices`. The defaults come from `Zr.getDefaults()` (PolySynth defaults). Let me check the default maxPolyphony value.

Key findings:
1. PolySynth option is `maxPolyphony` (default 32). I should use `maxPolyphony` instead of `maxVoices`. Default is 32 which already supports ≥3 simultaneous notes, but I'll set it explicitly to be safe.
2. `clockSource: "worker"` is the default for the Transport — that's what creates the worker and got blocked by CSP. I should set `Tone.Transport.clockSource = "interval"` to avoid the worker dependency. This is important because in the runner's sandboxed artifact, workers from blob URLs may be blocked; the fallback clock source "interval" uses setInterval. Let me set that before creating the synth.

Also, my console log referenced `synth.envelope` and `synth.maxVoices` which don't exist. For logging the ADSR, I can create the options object separately and log that, or access `synth._dummyVoice.envelope`. Better: define `const VOICE_OPTIONS = {...}` and pass it, then log VOICE_OPTIONS.envelope. Also `synth.maxPolyphony` exists.

Also the "worker" clockSource caused the CSP error at load. Setting clockSource to "interval" avoids it. Let me update:

```js
Tone.Transport.clockSource = "interval";
```

Hmm — does the Transport need to be running for a PolySynth to work? Tone.js 14's Transport is a ToneClock; even with clockSource worker/interval, scheduling via `now()` doesn't strictly require the transport to be started for one-shot notes? In Tone.js 14, `Tone.now()` is context.currentTime-based; the transport's clock is for signals/loops. Synth.triggerAttack uses the context time directly. But ToneContext may create the worker for the clock regardless. Setting clockSource="interval" should prevent worker creation.

Actually wait — the error occurred at page load, before any user gesture. Tone.js creates a Transport singleton at module init? The error says "Creating a worker from 'blob:...' violates CSP". So at load, Tone creates the transport with clockSource "worker". Setting `Tone.Transport.clockSource = "interval"` right after load (in our script, which runs after tone.min.js) should switch it. But the worker may already be created at module-eval time... The error appeared in the console at load. Hmm, was it at module eval or at Tone.start()/first use? The order in console: Tone banner, then worker CSP error, then AudioContext warnings, then "Synth created". So the worker was created during module evaluation (Tone.Transport singleton instantiated at import).

Actually in Tone.js 14.8, `Tone.Transport` is instantiated lazily? The singleton `Transport` is created when the Tone module loads (it's an export). The ToneClock default clockSource is "worker", and it may create the worker lazily on `start()`. But our console shows the error before "Synth created"... The AudioContext warnings also appeared before — those are from the ToneContext creation (Tone creates a default context at module init, and tries to resume it, hence autoplay warnings). The worker error also at init — meaning the Transport creates its worker eagerly.

Regardless: even if the worker was blocked, Tone.js may fall back or the clock might just fail silently. The important question: do notes actually play and get released properly? In Tone.js 14, if the transport clock fails, note scheduling via `Tone.now()` still works because Synth uses the audio context clock directly. The worker is used for the transport's ticking (needed for Tone.Loop, Transport scheduling, etc.), not for Synth envelopes — envelopes are param automation on the audio clock. So it should be fine even in the sandboxed runner.

But to be safe and clean, set `Tone.Transport.clockSource = "interval"` early — it prevents future worker creation attempts. The initial one at module load already happened though. Hmm, actually maybe the worker is created lazily when the clock starts (clock.start()). The Transport clock starts when... `Tone.start()`? Let me just test: set clockSource to "interval" and check console after interaction.

Also fix:
1. `maxVoices` → `maxPolyphony`
2. Fix the ADSR log to log the actual options object.
3. Add `Tone.Transport.clockSource = "interval";` before creating the synth.

Let me also verify note play via clicks and keys in the browser. Then check console for "note on/off" logs, and test blur release by dispatching... I can't dispatch events via the browser tool directly (no eval). Hmm — but I can simulate blur via key action? The browser tool has "key" action which presumably sends real key events to the page. Window blur can't be easily simulated without eval. I could add a tiny test hook... Actually I can test releaseAll indirectly: it's wired to `window blur` and `visibilitychange`. I can't easily trigger those from outside without eval. The code path is simple enough; I'll verify the pointer-outside-release case instead: press a key, drag outside, release — the drag action with pointer capture should still trigger pointerup on the key element. Let me test with a drag from a key to outside the piano.

Also auto-repeat: key action may support holding? Not sure. The e.repeat guard is standard.

Let me update the file now.

Now reload and test. Then click a key, check console for note on/off and audio activation. Let me reload first.

The ADSR log now shows correctly: `{"attack":0.02,"decay":0.25,"sustain":0.55,"release":0.9}` and maxPolyphony reports 32. Wait, it says maxPolyphony: 32, not 16. Interesting — I passed maxPolyphony: 16 but it reports 32. Let me look at the PolySynth constructor code: `this.options=Object.assign(e,t.options)` where `e = t.voice.getDefaults()` — the defaults of the *voice* (Synth), and `t.options` is... hmm. Let me re-read:

```js
const t = ui(Zr.getDefaults(), arguments, ["voice","options"]);
// t = normalized options with defaults from PolySynth.getDefaults()
Bn(!Nn(t.voice), "DEPRECATED...");
const e = t.voice.getDefaults();  // Synth defaults
this.options = Object.assign(e, t.options);  // voice defaults merged with t.options
this.voice = t.voice;
this.maxPolyphony = t.maxPolyphony;
```

So `this.maxPolyphony = t.maxPolyphony` where `t` is the merged options of PolySynth defaults + user options. So it should reflect user's maxPolyphony: 16. But it printed 32? Hmm, maybe `ui` (the option-merging helper) doesn't deep-merge properly, or... wait, maybe maxPolyphony default in Zr.getDefaults() is 32 and my user option was in `t.options`, and `ui` spreads... Let me check: `ui(Zr.getDefaults(), arguments, ["voice","options"])` — the third arg is a list of keys whose values are classes/constructors, so they're not deep-cloned. The user passed `{maxPolyphony:16, oscillator:{...}, envelope:{...}}`. Hmm, how does `ui` merge user options with defaults? If it does a shallow merge, maxPolyphony:16 should win over 32.

Wait, maybe the printed 32 comes from... `synth.maxPolyphony` printed 32. That means `t.maxPolyphony` was 32, meaning user's maxPolyphony didn't make it into t. Possibly because `ui` only picks known keys? Or maybe because the constructor signature is `PolySynth(voice, options)` and options IS merged... Let me test differently: does it matter? Default maxPolyphony is 32 which is ≥3, so requirement satisfied regardless. But I want to know why. Let me search the source for how PolySynth handles the options.

Actually, wait — maybe I should check: `this.maxPolyphony = t.maxPolyphony` — but which `t`? There's shadowing. The snippet: `lease=t=>this.releaseAll(t);const t=ui(Zr.getDefaults(),arguments,["voice","options"]);Bn(!Nn(t.voice),...);const e=t.voice.getDefaults();this.options=Object.assign(e,t.options),this.voice=t.voice,this.maxPolyphony=t.maxPolyphony,...`

Hmm so t.maxPolyphony should be 16 if ui merged correctly. Unless... `ui` is the `options`-merging function that merges constructor arguments with defaults — but when calling `new Tone.PolySynth(Tone.Synth, VOICE_OPTIONS)`, arguments = [Tone.Synth, VOICE_OPTIONS]. The defaults `Zr.getDefaults()` = {voice: ???, options: {}, maxPolyphony: 32}. Hmm, but wait — actually maybe Zr.getDefaults() has `voice: undefined` and `options: {}`. ui merges defaults with arguments... If arguments are merged positionally or by key? The signature-based merge: for a class constructor, Tone's `ui` (aka `options` helper) takes defaults, arguments, and a list of "deep" keys. It maps arguments to the defaults' keys in order? If defaults = {voice, options, maxPolyphony} and arguments = [Synth, VOICE_OPTIONS], then voice=Synth, options=VOICE_OPTIONS. Then t.options = VOICE_OPTIONS which includes maxPolyphony:16 — nested inside options! So `t.maxPolyphony` stays 32 (the PolySynth default), while my maxPolyphony:16 is inside `t.options`, merged into `this.options` which is passed to voice constructors... and voices ignore maxPolyphony.

Hmm wait, that doesn't seem right either. Let me check the actual PolySynth defaults: `Zr.getDefaults()` where Zr = PolySynth. In Tone.js source, PolySynth.getDefaults returns `{ voice: ..., options: {}, maxPolyphony: 32 }`? Hmm, actually in real Tone.js 14.8 source:

```ts
static getDefaults(): PolySynthOptions {
  return Object.assign(Monophonic.getDefaults?? no...
```

Actually from Tone.js source (PolySynth.ts):

```ts
static getDefaults(): PolySynthOptions {
  return {
    voice: Synth,
    options: {},
    maxPolyphony: 32,
    ...
  };
}
```

Hmm, but then in constructor:

```ts
const options = optionsFromArguments(PolySynth.getDefaults, arguments, ["voice", "options"]);
```

`optionsFromArguments` merges: it takes the defaults object and the arguments array, and assigns each argument to the corresponding key in the "keys" list. So argument[0] → options.voice, argument[1] → options.options. So user's VOICE_OPTIONS goes into `options.options`. Then:

```ts
const voiceOptions = options.options;
this.options = Object.assign(voice.getDefaults(), voiceOptions);
```

Wait no — `this.options = Object.assign(e, t.options)` — e is voice defaults, t.options is user's VOICE_OPTIONS. So this.options = voice defaults + user options (including maxPolyphony:16, which voices ignore). And `this.maxPolyphony = t.maxPolyphony` = 32 default.

Hmm! So how does a user actually set maxPolyphony? In Tone.js docs: `new Tone.PolySynth(Tone.Synth, { maxPolyphony: 16 })`? Hmm, but per this code, that would nest it inside options... unless optionsFromArguments is smarter: it might merge the argument object into defaults directly when there's a single object argument matching... Let me look at `optionsFromArguments` behavior. Actually in Tone.js, `optionsFromArguments(defaults, args, keys)`:

- If args has one argument and it's an object and defaults has no matching... Hmm.

Actually the real behavior: it checks if the argument at position i corresponds to keys[i]. keys = ["voice", "options"]. So arg0 (Tone.Synth class) → "voice", arg1 (VOICE_OPTIONS object) → "options". Yes, so user object lands in options.options.

Wait, but that contradicts Tone.js documentation examples: `const polySynth = new Tone.PolySynth(Tone.Synth, { envelope: {...} })` — envelope goes into options.options → merged into this.options → passed to each voice. That's exactly how envelope is passed to voices. And maxPolyphony in the same object would be... ignored by the voice, and NOT applied to the synth's maxPolyphony.

Hmm, so how do people set maxPolyphony then? Checking Tone.js docs for PolySynth: "maxPolyphony" is in PolySynthOptions which extends VoiceOptions... In the Tone.js docs example: 

```js
const synth = new Tone.PolySynth(Tone.Synth, {
  maxPolyphony: 8,
  ...
});
```

Hmm, I'm not 100% sure. Let me actually test empirically in the browser... I can't eval. Alternative: look at the minified optionsFromArguments (`ui`) implementation to understand.

Actually — hold on. Let me re-read the minified: `const t=ui(Zr.getDefaults(),arguments,["voice","options"])`. Let me find `ui` = the optionsFromArguments function and read its logic.

Let me extract the full `ui` function to understand the merging. It's `function ui(t,e,s=[],n){const i={...`. Let me grep a larger window.

Now I understand `optionsFromArguments` (function `ui`):

```js
function ui(t, e, s = [], n) {  // t=defaults, e=arguments, s=keys, n=?
  const i = {}, o = Array.from(e);
  // if first arg is a plain object (Pn), and n given, and first arg doesn't have property n,
  // and (some default keys exist in first arg OR nothing matched):
  if (Pn(o[0]) && n && !Reflect.has(o[0], n) && (Object.keys(o[0]).some(e => Reflect.has(t, e)) || (li(i, {[n]: o[0]}), s.splice(s.indexOf(n), 1), o.shift())),
      1 === o.length && Pn(o[0]))
    li(i, o[0]);  // single object arg -> merge all its keys into result
  else
    for (let t = 0; t < s.length; t++) In(o[t]) && (i[s[t]] = o[t]);  // positional mapping
  return li(t, i);  // merge defaults with i
}
```

Wait, that's hard to parse. Let me parse carefully:

```js
function ui(t, e, s = [], n) {
  const i = {}, o = Array.from(e);
  if (Pn(o[0]) && n && !Reflect.has(o[0], n) && (Object.keys(o[0]).some(e => Reflect.has(t, e)) || (li(i, {[n]: o[0]}), s.splice(s.indexOf(n), 1), o.shift())),
      1 === o.length && Pn(o[0]))
    li(i, o[0]);
  else
    for (let t = 0; t < s.length; t++) In(o[t]) && (i[s[t]] = o[t]);
  return li(t, i);
}
```

Hmm, the condition `Pn(o[0]) && n && ...` — `Pn` is probably `isObject`/`isPlainObject`, `n` is the 4th arg (a "single object arg name"?). For PolySynth, `ui(Zr.getDefaults(), arguments, ["voice","options"])` — n is undefined! So the first branch is skipped (n falsy). Then `1 === o.length && Pn(o[0])` — o.length is 2 (voice class + options object), so false → else branch: positional mapping: i.voice = o[0] = Synth class, i.options = o[1] = VOICE_OPTIONS. Then return li(t, i) — merge defaults t with i.

So t = {voice: undefined?, options: {}, maxPolyphony: 32, ...defaults} merged with {voice: Synth, options: VOICE_OPTIONS}.

Wait, what are Zr.getDefaults()? Let me check what PolySynth's defaults contain. Earlier grep showed `getDefaults(){return{` occurrences. Let me find PolySynth's (Zr) getDefaults.

Anyway: `t.maxPolyphony` = 32 from defaults — my VOICE_OPTIONS.maxPolyphony was nested into t.options, NOT applied to t.maxPolyphony. That's why it printed 32.

Then in constructor:
- `this.options = Object.assign(e, t.options)` — e = voice defaults, t.options = VOICE_OPTIONS → envelope applied to voices ✓ (each voice gets ADSR ✓)
- `this.maxPolyphony = t.maxPolyphony` = 32.

So maxPolyphony option in the second argument is IGNORED; it's 32 by default. Fine — 32 ≥ 3, requirement satisfied. But I'd rather set it properly. Options: set `synth.maxPolyphony = 16` after construction, or just leave 32. Actually is maxPolyphony used as a hard cap? `_collectGarbage` and "Max polyphony exceeded. Note dropped." — with 32 default, 13 notes max on our keyboard, so never exceeded. It's fine.

Simplest: pass envelope/oscillator via the second arg (correct per API), and set `synth.maxPolyphony = 16` after creation — or just log the default 32. Actually let me check how _collectGarbage uses maxPolyphony to confirm it's a live property. `this.maxPolyphony=t.maxPolyphony` — it's a plain property, so assigning post-construction works.

I'll set it explicitly after construction for clarity: `synth.maxPolyphony = 16;` Hmm, but the log prints synth.maxPolyphony after construction... I can set before logging. Actually simpler: remove maxPolyphony from VOICE_OPTIONS (since it's ignored there and misleading) and set the property directly. Let me restructure:

```js
const VOICE_OPTIONS = {
  oscillator: { type: "triangle" },
  envelope: { attack: 0.02, decay: 0.25, sustain: 0.55, release: 0.9 }
};
const synth = new Tone.PolySynth(Tone.Synth, VOICE_OPTIONS).toDestination();
synth.maxPolyphony = 16; // allow many simultaneous notes (>= 3 required)
console.log("Synth created — ADSR", JSON.stringify(VOICE_OPTIONS.envelope), "maxPolyphony:", synth.maxPolyphony);
```

Also the worker CSP error persists — it happens at module load before my clockSource assignment runs. Let me check where the worker is created: is it lazy (on clock start) or eager? The error appeared at load even before interaction. Tone.Transport is created at module init as a singleton. Its constructor creates a ToneClock with clockSource "worker". Does ToneClock create the worker in the constructor or on start()? Let me search for "new Worker" in the minified code.

Actually — does the worker even matter for Synth playback? In Tone.js 14, the Transport/Clock worker is used for precise scheduling of the transport clock. Synth envelopes are AudioParam automations scheduled on the audio clock — they don't need the transport. Notes will play and release correctly even if the worker is blocked. But let me check whether ToneClock falls back when worker creation fails. Let me find the worker creation code.

The clock creation code: `_createClock(){if("worker"===this._type)try{this._createWorker()}catch(t){this._type="timeout",this._createClock()}...}`.

So if `_createWorker()` throws, it falls back to "timeout". But in the browser, the CSP violation is reported as an error event/console error — does `new Worker(e)` actually throw, or does it just log an error and create a dead worker? Per CSP behavior, creating a worker that violates worker-src throws a SecurityError... Actually in Chrome, when CSP blocks worker creation, `new Worker()` throws a SecurityError synchronously? The console shows "error: Creating a worker from ... violates ... The action has been blocked." — this is typically logged as a console error, and the constructor throws. If it throws, Tone falls back to "timeout" clock source automatically. 

Either way — the transport clock is not needed for basic Synth note triggering (AudioParam scheduling on the audio clock). So playback should work. Setting `Tone.Transport.clockSource = "interval"`... hmm wait, what are the valid values? From defaults: `clockSource: "worker"`. The _createClock checks "worker" or "timeout". Hmm, is "interval" a valid value? Let me check ToneClock for valid clockSource values. In Tone.js 14, ClockSource = "worker" | "timeout" | "off". There's no "interval"! Let me verify.

Valid clock sources are "worker", "timeout", and "offline" (not "interval"). So my `Tone.Transport.clockSource = "interval"` is invalid — harmless since the clock only checks for "worker" or "timeout" (anything else does nothing, effectively "off"), but better to use a proper value. I'll set `Tone.Transport.clockSource = "timeout"` which uses setTimeout — works everywhere including sandboxed iframes where blob workers are blocked.

Note: the worker creation error at module load happens before my script runs (Tone.Transport singleton is created at module init). But the clock only calls _createClock() when started (probably on `Tone.start()` → transport start). Setting clockSource to "timeout" before first start avoids the worker attempt at start time. The initial error at load might be from... hmm, it happened at load before interaction. Maybe the transport clock starts eagerly. Whatever — with "timeout" set, subsequent starts will use setTimeout. Let me check when _createClock is called: probably in `start()`. The load-time error may have been from Tone.start() being auto-attempted? The AudioContext autoplay warnings suggest Tone tried to resume at load. Tone.js 14 auto-starts the transport when the context resumes... In any case, setting clockSource="timeout" is the right defensive move.

Also fix maxPolyphony: set property directly.

Let me update the file.

Now reload and interact: click a white key (C4), check highlight + console; click a black key; press keyboard keys; test a chord (multiple at once) — I can click multiple keys sequentially while holding? The browser "click" action clicks at coordinates and releases. For multi-note, I can use "key" action to press and hold keys? The "key" action likely sends keydown+keyup. Let me check what's available: click, drag, key, type. I'll do:

1. reload — check console for the new log.
2. click on a white key coordinate — expect "Audio activated" + "note on C4" + "note off C4".
3. click a black key — expect C#4.
4. key action "a" — expect note on/off C4.
5. type "awsd" maybe — sequential notes.
6. drag from a key to outside — test outside-release.

I need coordinates. The piano is centered, width min(94vw, 840px) in a 1200×800 viewport. Let me take a screenshot first to see the layout and get coordinates. Actually the screenshot says "model does not support images" — so I can't see images! I'll have to compute coordinates from the DOM. I can use "inspect" action to get DOM info, but coordinates? Let me try inspect on the piano element to see if it returns bounding boxes. The inspect action output earlier was just DOM text. Hmm.

Let me estimate: viewport 1200×800. The app is centered. Header ~90px tall, statusbar ~30px, piano top around y=180. Piano width: 94vw = 1128 → min(1128, 840) = 840px, so x from 180 to 1020. Piano padding 12/10. Inner keys area: x from ~190 to ~1010 (820 wide). White key width = 820/7 ≈ 117px. C4 is first white key: x ≈ 190–307, center ≈ 248. Keys height: clamp(210, 42vh=336, 320) = 320px. Piano top: let me compute more carefully.

Body: align-items center, padding 24px. App content height: header (~80) + statusbar (~35) + piano (~360 incl padding) + legend (~80) + hint (~90) ≈ 645px. Centered in 800 → top offset ≈ (800-645)/2 ≈ 77. So piano top ≈ 77+80+35+16 ≈ 208? Rough. White key vertical center ≈ 208+12+160 ≈ 380.

These estimates are rough. The "click" tool takes x,y in a 1200×800 viewport. Let me just try clicking around (250, 380) and check console for which note fired — the console log tells me the note, so I can verify the click landed on a key. If it misses, I'll adjust.

Actually, better: use the "inspect" action — maybe it returns element positions when given a target? The schema has no target param though. Let me just try the click approach with console feedback.

First reload.

The worker error still appears at load — it happens during Tone module evaluation (before my script runs), so I can't prevent that initial attempt. But Tone's code catches worker creation failure and falls back to "timeout" clock. My `clockSource = "timeout"` assignment prevents future attempts when the clock restarts. The error is cosmetic in this sandbox; in the final artifact the runner inlines tone.min.js the same way, so behavior will match. Importantly, does the worker error break note playback? The clock fallback handles it. Let's verify by clicking.

Now click on the first white key (C4). Estimated coordinates: piano area. Let me click at (250, 380) and see the console output.

Excellent! The click worked:
- "note on: C4" → "note off: C4" — correct note-start/note-release pair.
- "Audio activated via user gesture — AudioContext: running" — audio activated through the user gesture, context running.
- Status bar now shows "🔊 Audio active — Tone.js 14.8.49".

The "AudioContext is suspended" warnings are because Tone tried to schedule slightly before the context resumed — normal, and the note still played (attack scheduled at now which resolves after resume).

Now test:
1. A black key click (C#4). Black keys are at top 62% of the keys area. First black key (C#4) center x ≈ white boundary 1 at ~307 minus half black width. Black width = 0.62*117 ≈ 72.5, half ≈ 36. Center x ≈ 307-36 ≈ 271, y ≈ 220+12 + 0.31*320 ≈ 330. Let me click (271, 330).
2. Keyboard: press "A" (KeyA → C4), "W" (C#4), "K" (C5).
3. Chord: hold multiple keys — the "key" action may hold? I'll try pressing and check. Actually the key action probably does down+up quickly. For simultaneous test, I can use "type" with multiple characters — but that's sequential. True simultaneity is hard to verify with these tools; the code supports it via PolySynth with maxPolyphony 16 and per-source tracking. I can at least verify rapid sequential notes work.
4. Drag from a key to outside the piano to test outside-release (pointer capture path).
5. Test auto-repeat: the "key" action might hold the key down and produce repeats? Can't control. The e.repeat guard is in place.

Let me click the black key C#4.

Black key C#4 works: "note on: C#4" → "note off: C#4". The click landed on the black key correctly (the geometry is right).

Now test the computer keyboard. Use the "key" action with text "a" (KeyA → C4), then "w" (C#4), then "k" (C5). The key action probably takes a `text` param for the key. Let me press "a".

Keyboard "a" produced "note on: C4" → "note off: C4". Keyboard mapping works.

Now test:
1. A few more keys via "type" — e.g., type "wsk" to hit W→C#4, S→D4, K→C5 sequentially.
2. Drag test: press on a key and drag outside the piano, then release — verifies pointer capture + outside release. Use drag action from (250, 380) to (600, 100) — outside the piano.
3. Highlight check: I can't see screenshots (model doesn't support images), but the DOM "inspect" might show class attributes? The inspect output earlier showed DOM text only, not classes. Hmm. The highlight is applied via classList "active" — I can verify indirectly through the playingStatus element text: when a note is held, "Playing: C4" appears in the status bar. The DOM snapshot in each tool response includes the statusbar text. Let me use a "key" press with a hold... the key action likely doesn't hold. 

Alternative: use drag with slow movement to keep the pointer down while inspecting? The tools are sequential — during a drag call I get the result after release. Hmm.

Actually, let me check the "motion" action — maybe it can hold a pointer down at a position? The schema: action "motion" with delta, toX, toY, x, y. Not clear. Let me try "drag" first for the outside-release test; the console logs will show note on/off regardless of highlight visibility.

For highlight verification, I could rely on: the click already triggered note on/off, and the playingStatus updates in the same code path as the visual class toggle (setVisual does both). I can also verify the CSS class exists by inspecting the DOM after a click... but the click releases immediately.

Better idea: use the "key" action with capital "A" (shift) — no. Hmm, what about using drag starting on a key and ending outside — during drag the note stays on until release; after the drag completes, console shows note off. That verifies outside release. For highlight, the DOM snapshot in the drag response happens after release.

Alternative approach for highlight: temporarily... no, I shouldn't modify the app for testing. Actually — I CAN verify highlight differently: the `playingStatus` element content is set in setVisual alongside the class toggle. If I could trigger a note that stays held... The "type" action with a character sends keydown/keyup quickly. 

Hmm, what about the "motion" action? Let me just try drag first. Drag from (250,380) to (600,100): if pointer capture works, the key receives pointerup even outside → note off logs. Also the window pointerup safety net would catch it. Either way it proves no stuck note.

Let me also do a drag that ends on another key (e.g., from C4 to E4) — with pointer capture, the original key keeps ownership, so C4 releases and E4 does NOT trigger (correct behavior — no accidental note-on of a different key). The console would show only "note off: C4". That's a good verification of pointer capture semantics.

Let me run the type test first, then the two drags.

The "type" action didn't produce new note events — the console shows no new entries after the previous "note on: C4 / note off: C4" from the key action. Perhaps "type" targets a focused input element, or it types into the page but without key events reaching window? Or the type action requires a text field. The keyboard "key" action worked though. Let me test more individual keys with the "key" action: "w", "s", "k". Also test "e", "d", "f", "t", "g", "y", "h", "u", "j" — but that's many calls. Let me do a few key ones: "w" (C#4), "s" (D4), "k" (C5).

Then the drag test for outside release.

"w" → C#4 ✓, "s" → D4 ✓. Keyboard mapping is correct.

Now the drag test: press on C4 key (250, 380) and drag to outside the piano (e.g., 600, 100 — above the piano), then release. This verifies pointer capture / outside release. With pointer capture, the C4 key gets the pointerup → "note off: C4". Also no other note should trigger.

Then a second drag: from C4 (250,380) to another key (e.g., E4 area ~ x 480, y 380) — with capture, C4 releases, E4 does NOT sound. Console should show only "note off: C4".

Let me do the first drag.

The drag from C4 (250,380) to outside the piano (600,100) produced exactly "note on: C4" → "note off: C4" — the note started on press and was released even though the pointer was released far outside the key (pointer capture worked; no stuck note, and no spurious note-on of other keys while dragging over them).

Now the second drag test: from C4 to another white key (E4 at approx x=484, y=380) — with pointer capture, C4 should release and E4 should NOT trigger. Expected console: "note on: C4", "note off: C4" only.

Then I want to verify:
1. Highlight while held — I can't see screenshots, but I can verify via the DOM. Hmm, the inspect action returns DOM text without classes. Let me try "inspect" to see if it includes more detail like class attributes or the playingStatus. Actually earlier inspect wasn't used; reload returned "dom" as text content. The statusbar "Playing:" text would show in the DOM snapshot if a note were held. To have a held note during inspection, I'd need a tool action that holds... The drag completes before returning.

Alternative: verify highlight logic through the "playing" status text during a held key. Is there a way to hold a key? The "key" action might support a hold if I specify... The schema only has action/text. Probably down+up.

Hmm — what about the "motion" action? Let me try motion with x,y — maybe it moves the mouse without releasing (mouse down state?) Unclear. Let me try "motion" at a key position and then inspect to see if "Playing:" appears in the DOM. If motion presses/holds the mouse button... unlikely. Motion probably just moves the cursor.

Honestly, the highlight is toggled in the same setVisual() call that updates the "Playing:" status, and the status was verified working? Wait — actually I haven't seen the "Playing:" status in any DOM snapshot because all tests released the note before the snapshot. Let me at least verify the status text appears during a hold. 

Idea: use drag with a long path — no, still completes. 

Another idea: the browser tool might keep the mouse button held between separate tool calls if I use "motion" to press... Let me look at the motion action: "Run index.html, inspect DOM/console, interact, and see screenshots or motion frames." Motion frames suggest motion returns animation frames. Hmm.

Let me try: motion action with x=250, y=380 and see what it does. Then inspect. If the mouse button isn't pressed, nothing happens. 

Actually, a simpler robust verification of the highlight: temporarily add a URL-hash debug? No — don't modify the app for testing.

Wait — actually I CAN verify the highlight class through a different route: the console. No... the highlight doesn't log.

OK here's another thought: the requirement says "Check note/key labeling, any observable press-and-release highlighting". The DOM snapshots I receive show the playingStatus only when non-empty. During the drag, the note WAS held for the duration of the drag (several hundred ms), and the drag's response DOM snapshot is taken after release. So I can't observe it post-hoc.

Let me try the "motion" action to see if it can hold a pointer down. If not, I'll accept the code-path verification: setVisual() toggles both the "active" class and the status text atomically; the status text logic is identical to what I verified through console logs (note on/off pairs). The CSS for .active is straightforward. I'll note in the report that visual highlighting was verified via the shared code path and CSS, though not directly screenshotted (image viewing unavailable in this environment).

Actually wait — let me reconsider. Maybe I can hold a note using the drag action with a very slow movement... The drag action parameters don't include duration. Hmm.

What about pressing a key via "key" action with a capital letter or holding shift? No.

Let me try "motion" quickly to see its behavior.

Both tests passed:
1. Drag from C4 onto E4: console shows only "note on: C4" → "note off: C4" — E4 did NOT trigger (pointer capture keeps the original key as owner; no accidental note-on when sliding onto another key). ✓
2. Key "k" → C5 ✓ (the 13th note).

Verified so far:
- All 13 keys present with correct labels and mapping (DOM snapshot) ✓
- Mouse click on white key C4: on/off ✓, audio activation via gesture ✓, AudioContext running ✓
- Mouse click on black key C#4 ✓
- Keyboard A→C4, W→C#4, S→D4, K→C5 ✓
- Drag release outside piano → note released, no stuck note ✓
- Drag across keys → only the originally pressed key sounds/releases ✓

Remaining to verify:
- Highlight while held (visual) — can't view screenshots in this environment ("model does not support images"). The highlight class is toggled in setVisual() together with the "Playing:" status text. I could try the "motion" action to see if it holds a pointer... Let me try motion at a key and then inspect the DOM to see if "Playing:" appears. Worth one attempt.
- Blur/focus-loss release — can't easily simulate window blur with these tools; code path is shared with releaseAll which is exercised by... hmm, actually releaseAll is only wired to blur/visibilitychange. I can't trigger those. The logic is simple and mirrors noteOff. I'll note it as unverified-by-simulation but code-reviewed.
- Auto-repeat prevention — e.repeat guard present; can't easily simulate a held key repeat with the tools.
- Simultaneous notes (polyphony) — tools can't hold two keys at once easily... Actually! Can I? The "key" action sends one key. What about pressing mouse on one key (drag, holding) and... no, tools are sequential.

Hmm wait, actually let me think about whether I can verify polyphony and highlight together. What if I use the drag action but with a long route? The drag completes before the response returns. No.

What about the "motion" action? Let me try it — motion with x,y might just move the mouse. If the harness supports mouse-down state across calls, then: motion(x=250,y=380) — if it also presses... Let me just try and inspect the DOM after.

Actually, let me try a different approach for observing the held state: the "inspect" action. Maybe inspect returns richer DOM info (attributes/classes). Let me call inspect now (no notes held) to see its output format. Then try motion on a key + inspect to see if "Playing:" shows up.

The "motion" action just moves the cursor — no press, no new events. So I can't hold a note across tool calls to observe the highlight/Playing status in the DOM snapshot.

The verification I have:
- Every interaction produced perfectly paired "note on"/"note off" logs for the correct notes.
- setVisual() toggles the "active" CSS class and the "Playing:" status text together in the same function that the console logs confirm is running on every note on/off. So the highlight code path is exercised; only the pixel-level rendering is unobserved (image viewing unsupported here).

One more thing I can do: verify the highlight CSS/classes exist in the served HTML (they do — I wrote them) and that the classList.toggle calls are correct by code review. Also verify there are no JS errors in console (only the expected CSP worker warning from Tone's module init and autoplay warnings — all pre-existing Tone.js behaviors in a sandboxed iframe, none from my code).

Also double check: "Prevent keyboard auto-repeat" — e.repeat guard ✓ (code review).
"Release held voices when the pointer is released outside a key" — verified via drag ✓.
"window loses focus" — blur/visibilitychange handlers wired to releaseAll (code review; not simulatable with these tools).
"support at least three simultaneous notes" — PolySynth with maxPolyphony 16 (default 32), per-note voice management; per-source tracking allows the same note to be held by both keyboard and pointer without premature release.

One subtle bug to double-check: in `noteOn`, I check `const isNew = sources.size === 0;` BEFORE adding the source. If the note is already active from another source, sources.size > 0, so no re-trigger — correct (avoids double attack). If new, triggerAttack. ✓

In `noteOff`, only release when the set empties. ✓

Edge: keydown "A" held → auto-repeat events have e.repeat=true → ignored ✓. Keyup releases ✓.

Another edge: pointerdown on a key, then window blur → releaseAll clears all sources including pointer ones; if the pointer is later released, noteOff finds no sources → no-op ✓.

What about two pointers on the same key (multi-touch)? Each pointerdown adds its own source "p{id}"; each pointerup removes its own. Note releases when the last pointer lifts ✓.

What about the same pointer pressing a second key while holding the first? With pointer capture, the first key keeps the pointer; the second key won't get pointerdown. Correct behavior for mouse; multi-touch uses distinct pointerIds ✓.

I'm fairly confident in the implementation. One last check — the final file content, to make sure everything is in order. Let me read the final index.html to review it once more, particularly the script section.

Also, should I double check that there are no console errors from my code? The console shows no errors from my script (the only "error" is Tone's worker CSP at module init, which Tone internally handles with its timeout fallback — and note playback worked fine afterward, proving the clock fallback functions).

Let me do a final read of the file to confirm its current state, then finish. Also verify the file exists with correct name.

The file looks complete and correct. One small detail I notice: in `noteOn`, `const isNew = sources.size === 0;` is computed before `sources.add(source)` — correct.

One thing to double-check: `playingStatusEl.textContent` in setVisual reads `activeSources.size` — but for noteOff, we call `activeSources.delete(note)` BEFORE `setVisual(note, false)`, so the size is already updated. For noteOn, the source was already added before setVisual. ✓

Everything checks out. Final verification summary:

Verified in browser:
1. Initial render: all 13 keys C4–C5 with correct white/black layout, note labels, key badges (A W S E D F T G Y H U J K), and legend chips — seen in DOM snapshot.
2. Click on C4 (white key): "note on: C4" → "note off: C4", audio activated via gesture, AudioContext: running, status pill updated.
3. Click on C#4 (black key): correct on/off pair — black key geometry/positioning correct.
4. Keyboard: A→C4, W→C#4, S→D4, K→C5 — all correct on/off pairs.
5. Drag from C4 to outside the piano (600,100): note released — no stuck note (pointer capture works).
6. Drag from C4 across to E4: only C4 sounded and released; E4 did not trigger — pointer capture prevents accidental note-on.
7. Console: no JS errors from app code; ADSR config logged; only expected Tone.js module-level warnings (autoplay policy before gesture, and a CSP worker warning in the sandboxed test iframe which Tone.js internally falls back from — playback confirmed working).

Not directly verifiable with the available tools (noted in report):
- Pixel-level highlight rendering (screenshots unsupported in this environment) — but the highlight code path (setVisual toggling the "active" class) executes on every note on/off, as confirmed by the paired logs, and a "Playing: …" status pill mirrors the same state.
- Window-blur release and keyboard auto-repeat — handlers are wired (blur/visibilitychange → releaseAll; e.repeat guard) but can't be simulated with the available browser actions.
- True simultaneous multi-note hold — PolySynth with maxPolyphony 16 and per-source tracking supports it; tools can't hold two inputs at once.

Done. Write final report.