plan(0024): add zoom-out E2E case; resolve review-gate open items

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/superpowers/plans/2026-06-27-altitude-clip-pair-morph-lock.md

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+# Altitude Clip-Pair Morph + Lock Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** When the viewer changes altitude, choose the destination clip *first*, play the morph footage that goes from the currently-shown clip to that chosen clip, then lock the clip in place so it never changes again until the altitude changes.
+
+**Architecture:** Today the ring carries **5** per-edge morphs (each `scale_a → scale_b`, primary→primary), the server picks a random pool member only for the *landed* scale, and `advance()` plays the edge morph (which ends on the scale's *primary*) then does a *second*, jarring `fadeThroughBlack` swap to the randomly-chosen member. We replace the per-edge model with a **per-clip-pair** model: every pair of clips in adjacent altitudes gets its own morph, in both directions (**154** clips total). The server picks the destination member(s) *before* selecting the morph, threads the currently-shown clip in as the source, and chains morphs through each crossed altitude on a multi-detent jump. The renderer plays those exact morphs and locks on the final clip — no secondary swap, no re-roll while parked.
+
+**Tech Stack:** Python 3.13 / FastAPI (`simulator/app.py`), pure ring logic (`player/ring.py`), pure manifest/schema (`simulator/clips.py`), media baking via ffmpeg `xfade=zoomin` (`simulator/build_pool_manifest.py`), vanilla JS renderer (`simulator/static/app.js`), pytest, and a new Playwright E2E tier.
+
+## Global Constraints
+
+- **Morph file naming:** `transitions/<src_clip_id>__<dst_clip_id>.mp4` (double-underscore separator — clip ids themselves use single `_`, e.g. `cosmos_miri`). The zoom-out companion is `<src>__<dst>.rev.mp4` and represents the **reverse** direction (`dst → src`).
+- **Direction convention:** a morph is *baked* descending (higher altitude → lower altitude = zoom IN). The `.rev.mp4` companion is the ascending (zoom OUT) playback. The manifest lists **both** directions as explicit, separately-keyed entries so the renderer needs no reverse logic at play time.
+- **Ring order (descending, wraps):** `["cosmos", "orbit", "coast", "reef", "abyss"]`; `abyss → cosmos` is the wrap edge.
+- **Pool sizes (current):** cosmos 5, orbit 3, coast 4, reef 5, abyss 3 → **77** adjacent ordered-pair morphs descending + **77** reverse = **154** total transition clips.
+- **Lock invariant:** the displayed base clip changes **only** inside `advance()` (a deliberate altitude change) and the one initial `landScale()`. Nothing else may reload base media. The Dev-Mode re-roll button stays as an explicit dev affordance.
+- **Randomness stays injected:** `player/ring.py` is a pure module; the impure `random.random()` draw happens once at the API boundary (`simulator/app.py`). Pure functions take injected `float` picks in `[0,1)`.
+- **Back-compat:** a manifest with no `pool` (pool of one) and the synthesized single-clip fallback ring must still work. A pool-of-one scale needs no morphs to itself.
+
+---
+
+### Task 1: Manifest emits clip-pair transition entries
+
+Re-key the manifest builder from 5 per-edge entries to 154 per-clip-pair entries (both directions), each carrying `from`/`to` clip ids. Pure dict assembly — no ffmpeg.
+
+**Files:**
+- Modify: `simulator/build_pool_manifest.py:374-379` (`build_manifest()` transitions block)
+- Test: `tests/test_pipeline_manifest.py`
+
+**Interfaces:**
+- Consumes: module constants `RING_ORDER: list[str]`, `POOLS: dict[str, list[str]]`.
+- Produces: each transition dict shaped `{"from": <src_id>, "to": <dst_id>, "file": "transitions/<src>__<dst>.mp4", "model": "placeholder-zoom"}`. Forward entries are descending (`H→L`, `transitions/H__L.mp4`); reverse entries are ascending (`L→H`, `transitions/H__L.rev.mp4`).
+
+- [ ] **Step 1: Write the failing test**
+
+```python
+# tests/test_pipeline_manifest.py  (add)
+def test_transitions_are_per_clip_pair_both_directions():
+    import simulator.build_pool_manifest as b
+    m = b.build_manifest()
+    trans = m["ring"]["transitions"]
+    order = b.RING_ORDER
+    n = len(order)
+    # Every adjacent (higher H, lower L) edge, every member pair, BOTH directions.
+    expected = set()
+    for i in range(n):
+        H, L = order[i], order[(i + 1) % n]
+        for h in b.POOLS[H]:
+            for l in b.POOLS[L]:
+                expected.add((h, l, f"transitions/{h}__{l}.mp4"))        # zoom in
+                expected.add((l, h, f"transitions/{h}__{l}.rev.mp4"))    # zoom out
+    got = {(t["from"], t["to"], t["file"]) for t in trans}
+    assert got == expected
+    assert len(trans) == len(expected) == 154
+    assert all(t["model"] == "placeholder-zoom" for t in trans)
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `pytest tests/test_pipeline_manifest.py::test_transitions_are_per_clip_pair_both_directions -v`
+Expected: FAIL — current builder emits 5 `scale-scale` entries with no `from`/`to`.
+
+- [ ] **Step 3: Implement the per-clip-pair transitions block**
+
+```python
+# simulator/build_pool_manifest.py  — replace the transitions loop in build_manifest()
+    transitions = []
+    n = len(RING_ORDER)
+    for i in range(n):
+        H, L = RING_ORDER[i], RING_ORDER[(i + 1) % n]   # H higher altitude, L lower
+        for h in POOLS[H]:
+            for l in POOLS[L]:
+                fwd = f"transitions/{h}__{l}.mp4"        # zoom IN (descend H->L)
+                transitions.append({"from": h, "to": l, "file": fwd,
+                                    "model": "placeholder-zoom"})
+                transitions.append({"from": l, "to": h, "file": f"transitions/{h}__{l}.rev.mp4",
+                                    "model": "placeholder-zoom"})        # zoom OUT (ascend L->H)
+    return {"clips": clips, "ring": {"scales": scales, "transitions": transitions}}
+```
+
+- [ ] **Step 4: Run test to verify it passes**
+
+Run: `pytest tests/test_pipeline_manifest.py::test_transitions_are_per_clip_pair_both_directions -v`
+Expected: PASS
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add simulator/build_pool_manifest.py tests/test_pipeline_manifest.py
+git commit -m "feat(pipeline): manifest emits per-clip-pair morph transitions (both directions)"
+```
+
+---
+
+### Task 2: Bake the member-pair morph clips
+
+Generalize the ffmpeg morph recipe from scale-primary→scale-primary to any member→member, and have `generate_media()` bake every adjacent member pair forward + reverse. Tested with a stubbed ffmpeg runner so the test is fast and deterministic (the real bake runs as a media step at execution time).
+
+**Files:**
+- Modify: `simulator/build_pool_manifest.py:391-431` (`_make_transition`, `generate_media`)
+- Test: `tests/test_pipeline_manifest.py`
+
+**Interfaces:**
+- Consumes: `RING_ORDER`, `POOLS`, `MEDIA` (Path), member base footage at `MEDIA/<clip_id>/base.mp4`.
+- Produces: `_make_transition(ff, src_clip, dst_clip) -> Path` writing `transitions/<src>__<dst>.mp4` from the two members' `base.mp4`; `_make_reverse(ff, forward)` unchanged (writes `.rev.mp4`). `generate_media()` loops every adjacent ordered member pair.
+
+- [ ] **Step 1: Write the failing test (stubbed ffmpeg)**
+
+```python
+# tests/test_pipeline_manifest.py  (add)
+def test_generate_media_bakes_every_member_pair(monkeypatch, tmp_path):
+    import simulator.build_pool_manifest as b
+    calls = []
+    def fake_run(args, **kw):
+        # record the output path (last positional arg of each ffmpeg call)
+        calls.append(args[-1])
+        from pathlib import Path
+        Path(args[-1]).parent.mkdir(parents=True, exist_ok=True)
+        Path(args[-1]).write_bytes(b"x")
+        class R: returncode = 0
+        return R()
+    monkeypatch.setattr(b, "MEDIA", tmp_path)
+    monkeypatch.setattr(b.subprocess, "run", fake_run)
+    monkeypatch.setattr(b, "_ffmpeg", lambda: "ffmpeg")
+    b.generate_media()
+    outs = {str(p).split("transitions/")[-1] for p in calls}
+    # one forward + one reverse per adjacent member pair
+    fwd = {f"{h}__{l}.mp4" for H, L in b._adjacent_edges()
+           for h in b.POOLS[H] for l in b.POOLS[L]}
+    rev = {f"{h}__{l}.rev.mp4" for H, L in b._adjacent_edges()
+           for h in b.POOLS[H] for l in b.POOLS[L]}
+    assert fwd <= outs and rev <= outs
+    assert len(fwd) + len(rev) == 154
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `pytest tests/test_pipeline_manifest.py::test_generate_media_bakes_every_member_pair -v`
+Expected: FAIL — `_adjacent_edges` undefined and `generate_media` loops scales, not members.
+
+- [ ] **Step 3: Implement member-pair baking**
+
+```python
+# simulator/build_pool_manifest.py
+
+def _adjacent_edges() -> list[tuple[str, str]]:
+    """Ordered (higher, lower) altitude edges around the ring, including the wrap."""
+    n = len(RING_ORDER)
+    return [(RING_ORDER[i], RING_ORDER[(i + 1) % n]) for i in range(n)]
+
+
+def _make_transition(ff: str, src_clip: str, dst_clip: str) -> Path:
+    """A zoom/warp morph between two CLIP MEMBERS' base footage (the well-liked
+    orbit-coast recipe), keyed by clip id so every adjacent member pair gets its
+    own morph. Forward = zoom IN (descend src->dst)."""
+    a = MEDIA / src_clip / "base.mp4"
+    b = MEDIA / dst_clip / "base.mp4"
+    out = MEDIA / "transitions" / f"{src_clip}__{dst_clip}.mp4"
+    out.parent.mkdir(parents=True, exist_ok=True)
+    norm = "trim=0:3,setpts=PTS-STARTPTS,scale=1280:720,fps=25,setsar=1,format=yuv420p"
+    subprocess.run([
+        ff, "-y", "-i", str(a), "-i", str(b), "-filter_complex",
+        f"[0:v]{norm}[a];[1:v]{norm}[b];"
+        "[a][b]xfade=transition=zoomin:duration=1.5:offset=0.75,format=yuv420p[v]",
+        "-map", "[v]", "-an", str(out),
+    ], check=True, capture_output=True)
+    return out
+
+
+def generate_media() -> None:
+    """Bake EVERY adjacent member-pair morph from real bases — forward (zoom in,
+    descend) plus its reversed companion (zoom out, ascend)."""
+    ff = _ffmpeg()
+    for H, L in _adjacent_edges():
+        for h in POOLS[H]:
+            for l in POOLS[L]:
+                fwd = _make_transition(ff, h, l)
+                _make_reverse(ff, fwd)
+```
+
+- [ ] **Step 4: Run test to verify it passes**
+
+Run: `pytest tests/test_pipeline_manifest.py::test_generate_media_bakes_every_member_pair -v`
+Expected: PASS
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add simulator/build_pool_manifest.py tests/test_pipeline_manifest.py
+git commit -m "feat(pipeline): bake member-pair zoom morphs for every adjacent video combination"
+```
+
+---
+
+### Task 3: Clip-pair transition schema + morph lookup
+
+Change the `Transition` dataclass and ring loader to carry `from_clip`/`to_clip`, build a `(from, to) → file` lookup on the ring, and update the structural invariant. Touches both `player/ring.py` (dataclass + ring) and `simulator/clips.py` (parse + serialize).
+
+**Files:**
+- Modify: `player/ring.py:75-113` (`Transition`, `ScaleRing.__post_init__`, add `morph_for`)
+- Modify: `simulator/clips.py:88-131` (`load_ring` transition parse, `ring_to_dict` transitions block)
+- Test: `tests/test_player_ring.py`, `tests/test_clips.py`
+
+**Interfaces:**
+- Produces: `Transition(from_clip: str, to_clip: str, file: str, model: str = "")`.
+- Produces: `ScaleRing.morph_for(from_clip: str, to_clip: str) -> str | None` — the morph file for that directed pair, or `None` if absent.
+- `ScaleRing.__post_init__`: drop the "N edges == N transitions" rule (no longer per-edge); keep "≥1 scale, single-scale ring has no transitions". Build the lookup dict in `__post_init__` (store on a private attr via `object.__setattr__`, since the dataclass is frozen).
+- `ring_to_dict` transitions become `[{"from","to","file","model"}, ...]`.
+
+- [ ] **Step 1: Write the failing tests**
+
+```python
+# tests/test_player_ring.py  (add)
+from player.ring import Scale, Transition, ScaleRing
+
+def _two_member_ring():
+    scales = (Scale(id="cosmos", clip_id="c1", pool=("c1", "c2")),
+              Scale(id="abyss",  clip_id="a1", pool=("a1",)))
+    # adjacency wraps: cosmos<->abyss; members c1,c2 x a1 -> 2 pairs x2 dirs = 4
+    trans = (Transition("c1", "a1", "transitions/c1__a1.mp4"),
+             Transition("a1", "c1", "transitions/c1__a1.rev.mp4"),
+             Transition("c2", "a1", "transitions/c2__a1.mp4"),
+             Transition("a1", "c2", "transitions/c2__a1.rev.mp4"))
+    return ScaleRing(scales=scales, transitions=trans)
+
+def test_morph_for_returns_directed_file():
+    r = _two_member_ring()
+    assert r.morph_for("c1", "a1") == "transitions/c1__a1.mp4"
+    assert r.morph_for("a1", "c2") == "transitions/c2__a1.rev.mp4"
+    assert r.morph_for("c1", "c2") is None  # not an adjacent-altitude pair
+```
+
+```python
+# tests/test_clips.py  (add)
+def test_load_ring_parses_clip_pair_transitions(tmp_path):
+    import json
+    from simulator.clips import load_ring
+    m = {"ring": {"scales": [{"id": "x", "clip_id": "x1", "pool": ["x1"]},
+                              {"id": "y", "clip_id": "y1", "pool": ["y1"]}],
+                  "transitions": [{"from": "x1", "to": "y1", "file": "transitions/x1__y1.mp4"},
+                                  {"from": "y1", "to": "x1", "file": "transitions/x1__y1.rev.mp4"}]}}
+    p = tmp_path / "manifest.json"; p.write_text(json.dumps(m))
+    ring = load_ring(p)
+    assert ring.morph_for("x1", "y1") == "transitions/x1__y1.mp4"
+    assert ring.morph_for("y1", "x1") == "transitions/x1__y1.rev.mp4"
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `pytest tests/test_player_ring.py::test_morph_for_returns_directed_file tests/test_clips.py::test_load_ring_parses_clip_pair_transitions -v`
+Expected: FAIL — `Transition` has no `from_clip`/`to_clip`; no `morph_for`.
+
+- [ ] **Step 3: Implement the schema + lookup**
+
+```python
+# player/ring.py — replace the Transition dataclass
+@dataclass(frozen=True)
+class Transition:
+    """A pre-baked zoom/warp morph between TWO specific clips in adjacent
+    altitudes. `file` plays as-is (the manifest holds both directions as
+    separate, directed entries — forward zoom-in and `.rev` zoom-out)."""
+    from_clip: str
+    to_clip: str
+    file: str
+    model: str = ""
+```
+
+```python
+# player/ring.py — ScaleRing: relax the invariant, build the lookup
+@dataclass(frozen=True)
+class ScaleRing:
+    scales: tuple[Scale, ...]
+    transitions: tuple[Transition, ...]
+
+    def __post_init__(self) -> None:
+        if len(self.scales) == 0:
+            raise RingError("a ScaleRing needs at least one scale")
+        lookup = {(t.from_clip, t.to_clip): t.file for t in self.transitions}
+        object.__setattr__(self, "_morphs", lookup)
+
+    def __len__(self) -> int:
+        return len(self.scales)
+
+    def morph_for(self, from_clip: str, to_clip: str) -> str | None:
+        """The morph file for the directed clip pair, or None if none baked."""
+        return self._morphs.get((from_clip, to_clip))
+```
+
+```python
+# simulator/clips.py — load_ring transition parse (replace lines 101-104)
+    transitions = tuple(
+        Transition(
+            from_clip=t.get("from", ""),
+            to_clip=t.get("to", ""),
+            file=t["file"],
+            model=t.get("model", ""),
+        )
+        for t in ring.get("transitions", [])
+    )
+```
+
+```python
+# simulator/clips.py — ring_to_dict transitions block (replace line 130)
+        "transitions": [
+            {"from": t.from_clip, "to": t.to_clip, "file": t.file, "model": t.model}
+            for t in ring.transitions
+        ],
+```
+
+- [ ] **Step 4: Run the tests + the existing ring/clips suites**
+
+Run: `pytest tests/test_player_ring.py tests/test_clips.py -v`
+Expected: PASS — fix any existing test that constructed `Transition(file=..., model=...)` positionally to the new 3-arg form (`Transition(from_clip, to_clip, file)`), and any test asserting the old `N == N` invariant.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add player/ring.py simulator/clips.py tests/test_player_ring.py tests/test_clips.py
+git commit -m "feat(ring): clip-pair Transition schema + morph_for lookup"
+```
+
+---
+
+### Task 4: Resolve chained member→member morphs (pick before transition)
+
+Add a pure function that, given a structural `RingMove`, the currently-shown clip, and one injected pick per step, walks the steps — choosing a destination member for each crossed altitude and resolving the morph from the *previous* clip to it — and reports the final locked clip. This is the heart of "choose the clip first, then play the matching morph," chained through each altitude.
+
+**Files:**
+- Modify: `player/ring.py` (add `MorphStep`, `ResolvedMove`, `resolve_move`)
+- Test: `tests/test_player_ring.py`
+
+**Interfaces:**
+- Consumes: `RingMove` (from `advance_ring`), `pick_clip_id`, `scale_at`, `ScaleRing.morph_for`.
+- Produces:
+  - `MorphStep(from_clip: str, to_clip: str, file: str | None, to_index: int, blended: bool)`
+  - `ResolvedMove(steps: tuple[MorphStep, ...], target_clip_id: str)`
+  - `resolve_move(ring: ScaleRing, move: RingMove, from_clip_id: str, picks: tuple[float, ...]) -> ResolvedMove` — `len(picks)` must equal `len(move.steps)`; each `picks[k]` chooses the member of the scale that step `k` lands on. `from_clip` of step 0 is `from_clip_id`; each subsequent step's `from_clip` is the prior step's `to_clip`. `target_clip_id` is the last step's `to_clip` (or `from_clip_id` for an empty move).
+
+- [ ] **Step 1: Write the failing tests**
+
+```python
+# tests/test_player_ring.py  (add)
+from player.ring import advance_ring, resolve_move
+
+def _chain_ring():
+    # 3 scales, pools of 2/1/2; descending edges cosmos->coast->abyss + wrap abyss->cosmos
+    scales = (Scale("cosmos", "c1", ("c1", "c2")),
+              Scale("coast",  "o1", ("o1",)),
+              Scale("abyss",  "a1", ("a1", "a2")))
+    t = []
+    def pair(h, l):
+        t.append(Transition(h, l, f"transitions/{h}__{l}.mp4"))
+        t.append(Transition(l, h, f"transitions/{h}__{l}.rev.mp4"))
+    for h in ("c1", "c2"):
+        pair(h, "o1")            # cosmos<->coast
+    for h in ("o1",):
+        pair(h, "a1"); pair(h, "a2")   # coast<->abyss
+    for h in ("a1", "a2"):
+        pair(h, "c1"); pair(h, "c2")   # abyss<->cosmos (wrap)
+    return ScaleRing(scales=scales, transitions=tuple(t))
+
+def test_resolve_single_step_zoom_in():
+    r = _chain_ring()
+    move = advance_ring(r, from_index=0, delta=1)        # cosmos -> coast
+    res = resolve_move(r, move, from_clip_id="c2", picks=(0.0,))
+    assert len(res.steps) == 1
+    s = res.steps[0]
+    assert (s.from_clip, s.to_clip) == ("c2", "o1")
+    assert s.file == "transitions/c2__o1.mp4"
+    assert res.target_clip_id == "o1"
+
+def test_resolve_chains_through_intermediate_altitude():
+    r = _chain_ring()
+    move = advance_ring(r, from_index=0, delta=2)        # cosmos -> coast -> abyss
+    # pick coast member (only o1) then abyss member: 0.6*2 -> index 1 -> a2
+    res = resolve_move(r, move, from_clip_id="c1", picks=(0.0, 0.6))
+    files = [s.file for s in res.steps]
+    assert files == ["transitions/c1__o1.mp4", "transitions/o1__a2.mp4"]
+    assert res.target_clip_id == "a2"
+
+def test_resolve_zoom_out_uses_reverse_file():
+    r = _chain_ring()
+    move = advance_ring(r, from_index=2, delta=-1)       # abyss -> coast (ascend)
+    res = resolve_move(r, move, from_clip_id="a1", picks=(0.0,))
+    assert res.steps[0].file == "transitions/o1__a1.rev.mp4"
+    assert res.target_clip_id == "o1"
+
+def test_resolve_empty_move_keeps_source():
+    r = _chain_ring()
+    move = advance_ring(r, from_index=0, delta=0)
+    res = resolve_move(r, move, from_clip_id="c2", picks=())
+    assert res.steps == () and res.target_clip_id == "c2"
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `pytest tests/test_player_ring.py -k resolve -v`
+Expected: FAIL — `resolve_move` undefined.
+
+- [ ] **Step 3: Implement `resolve_move`**
+
+```python
+# player/ring.py  (add near the bottom)
+
+@dataclass(frozen=True)
+class MorphStep:
+    """One morph to play while advancing: from the clip currently shown to the
+    chosen clip of the next altitude, the morph file, the index it lands on, and
+    whether it plays fast (a fast-spin pass)."""
+    from_clip: str
+    to_clip: str
+    file: str | None
+    to_index: int
+    blended: bool
+
+
+@dataclass(frozen=True)
+class ResolvedMove:
+    steps: tuple[MorphStep, ...]
+    target_clip_id: str
+
+
+def resolve_move(
+    ring: ScaleRing,
+    move: RingMove,
+    from_clip_id: str,
+    picks: tuple[float, ...],
+) -> ResolvedMove:
+    """Choose the destination clip for each crossed altitude (injected `picks`,
+    one per step) and resolve the morph from the previous clip to it. The morph
+    is chosen AFTER the destination clip, so the footage matches what we land on.
+    `file` is None if no morph was baked for a pair (renderer falls back to a
+    plain cut); `target_clip_id` is the final locked clip."""
+    if len(picks) != len(move.steps):
+        raise ValueError(f"need one pick per step: {len(picks)} != {len(move.steps)}")
+    steps: list[MorphStep] = []
+    src = from_clip_id
+    for st, r in zip(move.steps, picks):
+        dst_scale = scale_at(ring, st.to_index)
+        dst = pick_clip_id(dst_scale, r)
+        steps.append(MorphStep(
+            from_clip=src,
+            to_clip=dst,
+            file=ring.morph_for(src, dst),
+            to_index=st.to_index,
+            blended=st.blended,
+        ))
+        src = dst
+    return ResolvedMove(steps=tuple(steps), target_clip_id=src)
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `pytest tests/test_player_ring.py -k resolve -v`
+Expected: PASS
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add player/ring.py tests/test_player_ring.py
+git commit -m "feat(ring): resolve_move picks destination clip then matching morph, chained"
+```
+
+---
+
+### Task 5: Fast spin plays the whole chain quickly (no collapse)
+
+The operator chose "chain through each altitude," with fast spins playing that chain *quickly* rather than collapsing to a single arrival pass. Change `advance_ring`'s fast-spin branch to keep every step but mark each `blended=True` (so the renderer plays each morph at `FAST_BLEND_RATE`) and still set `RingMove.fast=True`.
+
+**Files:**
+- Modify: `player/ring.py:219-241` (fast-spin branch in `advance_ring`)
+- Test: `tests/test_player_ring.py`
+
+**Interfaces:**
+- Unchanged signature. Behavior change: a fast spin returns **all** steps (each `blended=True`), not one collapsed step.
+
+- [ ] **Step 1: Write the failing test (and update any existing fast-spin assertions)**
+
+```python
+# tests/test_player_ring.py  (add)
+def test_fast_spin_keeps_all_steps_blended():
+    r = _chain_ring()                       # 3-scale ring from Task 4
+    move = advance_ring(r, from_index=0, delta=3, fast_spin_threshold=3)
+    assert move.fast is True
+    assert len(move.steps) == 3             # NOT collapsed to 1
+    assert all(s.blended for s in move.steps)
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `pytest tests/test_player_ring.py::test_fast_spin_keeps_all_steps_blended -v`
+Expected: FAIL — current branch collapses to a single `(blended,)` step.
+
+- [ ] **Step 3: Implement the chain-fast branch**
+
+```python
+# player/ring.py — replace the fast-spin collapse block (lines ~219-237)
+    if fast_spin_threshold >= 2 and abs(delta) >= fast_spin_threshold:
+        fast_steps = tuple(
+            TransitionStep(edge=s.edge, reversed=s.reversed, file=s.file,
+                           to_index=s.to_index, blended=True)
+            for s in steps
+        )
+        return RingMove(from_index=start, to_index=index, steps=fast_steps,
+                        wrapped=wrapped, fast=True)
+```
+
+- [ ] **Step 4: Run the full ring suite (catch the old collapse test)**
+
+Run: `pytest tests/test_player_ring.py -v`
+Expected: PASS — update/replace any prior test that asserted fast spin yields exactly one step.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add player/ring.py tests/test_player_ring.py
+git commit -m "feat(ring): fast spin plays the full morph chain quickly instead of collapsing"
+```
+
+---
+
+### Task 6: API picks before transitioning and serializes the resolved chain
+
+`/api/ring/advance` accepts the currently-shown clip (`from_clip_id`), draws one random pick per step, resolves the chained morphs, and returns the resolved steps + locked `target_clip_id`. Also extend `media-versions` to cover every transition file.
+
+**Files:**
+- Modify: `simulator/app.py:119-121` (`RingAdvanceRequest`), `:237-252` (`api_ring_advance`), `:213-229` (`api_media_versions`)
+- Modify: `simulator/clips.py:134-160` (`ring_move_to_dict` → resolved-move serializer)
+- Test: `tests/test_simulator_api.py`
+
+**Interfaces:**
+- `RingAdvanceRequest`: add `from_clip_id: str = ""`.
+- New serializer `resolved_move_to_dict(move: RingMove, resolved: ResolvedMove) -> dict`:
+  ```json
+  {"from_index": int, "to_index": int, "wrapped": bool, "fast": bool,
+   "target_clip_id": str,
+   "steps": [{"from_clip": str, "to_clip": str, "file": str|null,
+              "to_index": int, "blended": bool}, ...]}
+  ```
+- `media-versions`: iterate `t.file` for every transition (no `.rev` derivation — both directions are explicit entries now).
+
+- [ ] **Step 1: Write the failing test**
+
+```python
+# tests/test_simulator_api.py  (add)
+def test_advance_picks_then_returns_matching_morph(client):
+    # client fixture serves the sample_media manifest
+    r = client.post("/api/ring/advance",
+                    json={"from_index": 0, "delta": 1, "from_clip_id": "cosmos"})
+    assert r.status_code == 200
+    body = r.json()
+    assert body["to_index"] == 1
+    target = body["target_clip_id"]
+    step = body["steps"][-1]
+    assert step["from_clip"] == "cosmos"          # threaded current clip
+    assert step["to_clip"] == target              # morph lands on the locked clip
+    # file matches the directed pair (zoom-in descend, forward file)
+    assert step["file"] == f"transitions/cosmos__{target}.mp4"
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `pytest tests/test_simulator_api.py::test_advance_picks_then_returns_matching_morph -v`
+Expected: FAIL — response has no `from_clip`/`to_clip`, file is the old per-edge name.
+
+- [ ] **Step 3: Implement request field, endpoint, serializer, media-versions**
+
+```python
+# simulator/app.py
+class RingAdvanceRequest(BaseModel):
+    from_index: int = 0
+    delta: int
+    from_clip_id: str = ""
+```
+
+```python
+# simulator/app.py — api_ring_advance
+    @app.post("/api/ring/advance")
+    def api_ring_advance(req: RingAdvanceRequest):
+        if app.state.ring is None:
+            raise HTTPException(status_code=404, detail="no scale ring in manifest")
+        move = advance_ring(app.state.ring, req.from_index, req.delta,
+                            fast_spin_threshold=DEFAULT_FAST_SPIN_THRESHOLD)
+        # Choose the destination member of each crossed altitude FIRST (one random
+        # draw per step), then resolve the morph from the prior clip to it.
+        src = req.from_clip_id or scale_at(app.state.ring, move.from_index).clip_id
+        picks = tuple(random.random() for _ in move.steps)
+        resolved = resolve_move(app.state.ring, move, src, picks)
+        return resolved_move_to_dict(move, resolved)
+```
+
+```python
+# simulator/clips.py — replace ring_move_to_dict with resolved_move_to_dict
+def resolved_move_to_dict(move, resolved) -> dict:
+    """JSON form of a resolved encoder move: where it lands, the locked clip, and
+    the ordered chained morphs (each from the prior clip to its chosen
+    destination, with the matching morph file)."""
+    return {
+        "from_index": move.from_index,
+        "to_index": move.to_index,
+        "wrapped": move.wrapped,
+        "fast": move.fast,
+        "target_clip_id": resolved.target_clip_id,
+        "steps": [
+            {"from_clip": s.from_clip, "to_clip": s.to_clip, "file": s.file,
+             "to_index": s.to_index, "blended": s.blended}
+            for s in resolved.steps
+        ],
+    }
+```
+
+```python
+# simulator/app.py — api_media_versions: cover every transition file explicitly
+        files = {c.base_file for c in app.state.clips}
+        if app.state.ring is not None:
+            for t in app.state.ring.transitions:
+                files.add(t.file)
+```
+
+Update imports in `simulator/app.py` (`resolve_move`, `scale_at` already imported; add `resolve_move`) and `simulator/clips.py` (drop `ring_move_to_dict`, add `resolved_move_to_dict`; remove the now-unused `_rev_file` if nothing else uses it — grep first).
+
+- [ ] **Step 4: Run the API suite**
+
+Run: `pytest tests/test_simulator_api.py -v`
+Expected: PASS — fix any test referencing the removed `ring_move_to_dict` / old response shape.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add simulator/app.py simulator/clips.py tests/test_simulator_api.py
+git commit -m "feat(api): /api/ring/advance picks clip then returns matching chained morphs"
+```
+
+---
+
+### Task 7: Renderer plays the chosen morph and locks the clip (no secondary swap)
+
+Rewire the frontend: send the currently-shown clip, play each resolved morph straight (the manifest already encodes direction, so drop the `reversed`/`reverseFile` logic), land + lock on `target_clip_id` with a plain (re)load, and **delete the secondary `fadeThroughBlack` swap**. Build a `(from,to)→file` lookup from the ring and preload only the morphs reachable from the current locked clip, refreshed on each landing (154 clips is too many to preload eagerly).
+
+**Files:**
+- Modify: `simulator/static/app.js` — `advance` (620-652), `playTransition` (568-595), `onload`/ring load (33-57), `preloadOrder`/`preloadList`/`reverseFile` (104-131, 566), remove `fadeThroughBlack` (600-618) call.
+- Verified by: Task 8 (E2E) + manual run.
+
+**Interfaces:**
+- Consumes the Task 6 response: `move.steps[k] = {from_clip, to_clip, file, to_index, blended}`, `move.target_clip_id`.
+- New module state: `morphByPair = {}` — `"from→to"` → file string, built from `ring.transitions`.
+
+- [ ] **Step 1: Build the morph lookup when the ring loads**
+
+```javascript
+// simulator/static/app.js — in loadRing(), after `ring = ...` is set:
+  morphByPair = {};
+  if (ring && ring.transitions)
+    for (const t of ring.transitions) morphByPair[`${t.from}→${t.to}`] = t.file;
+```
+
+Add `let morphByPair = {};` near the other module state (around line 38). The synthesized single-clip fallback ring has no transitions → empty lookup → advance is a no-op (pool of one), which is correct.
+
+- [ ] **Step 2: Simplify `playTransition` (no reverse logic)**
+
+```javascript
+// simulator/static/app.js — replace playTransition
+function playTransition(file, blended) {
+  // Play one resolved morph start-to-finish with alteration layers hidden. The
+  // manifest already encodes direction (forward zoom-in vs `.rev` zoom-out), so
+  // the file is played as-is. A fast-spin step runs at FAST_BLEND_RATE. If no
+  // morph exists for the pair (file null), resolve immediately (plain cut).
+  return new Promise((resolve) => {
+    if (!file) return resolve();
+    overlay.style.opacity = "0"; affectLayer.style.opacity = "0"; tint.style.opacity = "0";
+    vid.style.filter = "none"; vid.loop = false; vid.style.opacity = "1";
+    vid.src = mediaUrl(file);
+    vid.playbackRate = blended ? FAST_BLEND_RATE : 1;
+    let done = false;
+    const finish = () => {
+      if (done) return; done = true;
+      vid.removeEventListener("ended", finish); vid.playbackRate = 1; resolve();
+    };
+    vid.addEventListener("ended", finish);
+    vid.play().catch(finish);
+    setTimeout(finish, blended ? 3000 : 6000);
+  });
+}
+```
+
+- [ ] **Step 3: Rewrite `advance` — pick first (via server), play morphs, lock, no swap**
+
+```javascript
+// simulator/static/app.js — replace advance
+async function advance(delta) {
+  if (busy || !ring || ring.scales.length < 2) return;
+  busy = true;
+  try {
+    const resp = await fetch("/api/ring/advance", {
+      method: "POST", headers: { "content-type": "application/json" },
+      body: JSON.stringify({ from_index: ringIndex, delta, from_clip_id: activeClipId }),
+    });
+    if (!resp.ok) return;
+    const move = await resp.json();
+    for (const step of move.steps) {
+      await playTransition(step.file, step.blended);
+    }
+    ringIndex = move.to_index;
+    activeClipId = move.target_clip_id;   // the locked clip — the morph ended on it
+    currentClipId = null;                 // force ensureClipMedia to (re)load + loop it
+    renderScaleReadout();
+  } finally {
+    busy = false;
+    update();                 // ensureClipMedia loads the locked clip; nothing re-rolls
+    applyAudio();
+    refreshReachablePreload();
+  }
+}
+```
+
+Then **delete** `fadeThroughBlack` (now unused) and `reverseFile` (the `.rev` companion is an explicit manifest entry, no longer derived). Grep to confirm no other callers before deleting.
+
+- [ ] **Step 4: Preload only the reachable morphs, refreshed per landing**
+
+```javascript
+// simulator/static/app.js — replace the eager transition preload in preloadOrder()/preloadList()
+// Reachable morphs from the CURRENT locked clip: to/from every member of the
+// neighboring altitudes (the only clips one detent can reach). 154 total is too
+// many to preload up front; we focus on what the next move can need.
+function reachableMorphFiles() {
+  const files = new Set();
+  if (!ring || ring.scales.length < 2 || !activeClipId) return files;
+  const n = ring.scales.length;
+  for (const sign of [1, -1]) {
+    const nb = ring.scales[((ringIndex + sign) % n + n) % n];
+    const members = (nb.pool || [{ clip_id: nb.clip_id }]).map((m) => m.clip_id);
+    for (const m of members) {
+      const a = morphByPair[`${activeClipId}→${m}`];
+      const b = morphByPair[`${m}→${activeClipId}`];
+      if (a) files.add(a);
+      if (b) files.add(b);
+    }
+  }
+  return files;
+}
+function refreshReachablePreload() {
+  // Kick a background cache fill of the reachable morphs (bounded concurrency,
+  // same cacheClip helper used for bases). Idempotent — cached files are skipped.
+  for (const f of reachableMorphFiles()) cacheClip(f);
+}
+```
+
+In `preloadOrder()` replace the `if (ring.transitions) for (const t ...) { add(t.file); add(reverseFile(t.file)); }` block with `for (const f of reachableMorphFiles()) add(f);`. Keep base-clip preloading (current + neighbor pools) as-is. (`cacheClip` = factor out the per-file fetch→blob step already inside the preload loop so `refreshReachablePreload` can reuse it.)
+
+- [ ] **Step 5: Manual smoke + commit**
+
+Run: `cd simulator && python -m uvicorn app:app --port 8011` then open `http://localhost:8011/`, turn the Altitude dial one detent each way and several detents; confirm: a zoom morph plays, it lands on a clip, and that clip **does not change** while parked (watch the Dev-Mode clip readout). No black-flash second swap.
+
+```bash
+git add simulator/static/app.js
+git commit -m "feat(sim): play chosen morph then lock clip per altitude; drop secondary swap"
+```
+
+---
+
+### Task 8: Playwright E2E — lock + matching morph (new tier)
+
+Stand up a minimal Playwright tier (none exists) and add one spec that proves the two behaviors the operator asked for: after zooming, the displayed clip is stable (locked) until the next altitude change, and the morph that plays matches `from→to`. §9 requires an E2E browser tier for this UI change.
+
+**Files:**
+- Create: `simulator/e2e/package.json`, `simulator/e2e/playwright.config.ts`, `simulator/e2e/tests/altitude-lock.spec.ts`
+- Create: `simulator/e2e/README.md` (how to run; how it boots uvicorn)
+
+**Interfaces:**
+- The spec drives the real app (uvicorn on a fixed port via Playwright `webServer`), reads the Dev-Mode clip readout (enable Dev Mode via localStorage before load), and intercepts `/media/transitions/*` requests to assert the morph file played.
+
+- [ ] **Step 1: Scaffold the tier (failing because no test yet)**
+
+```jsonc
+// simulator/e2e/package.json
+{ "name": "hef-e2e", "private": true,
+  "scripts": { "test": "playwright test" },
+  "devDependencies": { "@playwright/test": "^1.45.0" } }
+```
+
+```ts
+// simulator/e2e/playwright.config.ts
+import { defineConfig } from "@playwright/test";
+export default defineConfig({
+  testDir: "./tests",
+  webServer: {
+    command: "cd .. && python -m uvicorn app:app --port 8099",
+    url: "http://localhost:8099/api/clips",
+    reuseExistingServer: !process.env.CI,
+    timeout: 60_000,
+  },
+  use: { baseURL: "http://localhost:8099" },
+});
+```
+
+- [ ] **Step 2: Write the spec**
+
+```ts
+// simulator/e2e/tests/altitude-lock.spec.ts
+import { test, expect } from "@playwright/test";
+
+test("zoom plays a morph, lands locked, and does not change while parked", async ({ page }) => {
+  const morphs: string[] = [];
+  page.on("request", (r) => {
+    const m = r.url().match(/\/media\/(transitions\/[^?]+)/);
+    if (m) morphs.push(m[1]);
+  });
+  await page.addInitScript(() => localStorage.setItem("hef.devMode", "1"));
+  await page.goto("/");
+  const readout = page.locator("#scale-name");
+  await expect(readout).toContainText("cosmos");
+
+  // Zoom inward one altitude (wheel down = +). A morph must play.
+  await page.locator("#stage").dispatchEvent("wheel", { deltaY: 120 });
+  await page.waitForTimeout(2500);
+  expect(morphs.some((f) => f.startsWith("transitions/cosmos__"))).toBeTruthy();
+
+  // The landed clip is now locked: capture it, wait through several alteration
+  // ticks, and assert it never changes.
+  const landed = (await readout.textContent())!;
+  await page.waitForTimeout(2000);
+  expect(await readout.textContent()).toBe(landed);
+});
+
+test("zooming back OUT plays a reverse morph and lands locked", async ({ page }) => {
+  const morphs: string[] = [];
+  page.on("request", (r) => {
+    const m = r.url().match(/\/media\/(transitions\/[^?]+)/);
+    if (m) morphs.push(m[1]);
+  });
+  await page.addInitScript(() => localStorage.setItem("hef.devMode", "1"));
+  await page.goto("/");
+  const readout = page.locator("#scale-name");
+  await expect(readout).toContainText("cosmos");
+
+  // Zoom inward one altitude, then back OUT (wheel up = -). The outward move must
+  // play a `.rev` morph and land back on cosmos, locked.
+  await page.locator("#stage").dispatchEvent("wheel", { deltaY: 120 });
+  await page.waitForTimeout(2500);
+  morphs.length = 0;                                  // only watch the zoom-out move
+  await page.locator("#stage").dispatchEvent("wheel", { deltaY: -120 });
+  await page.waitForTimeout(2500);
+  expect(morphs.some((f) => /transitions\/cosmos__.*\.rev\.mp4/.test(f))).toBeTruthy();
+  await expect(readout).toContainText("cosmos");
+
+  // Locked after the outward move too.
+  const landed = (await readout.textContent())!;
+  await page.waitForTimeout(2000);
+  expect(await readout.textContent()).toBe(landed);
+});
+```
+
+- [ ] **Step 3: Install + run**
+
+Run: `cd simulator/e2e && npm install && npx playwright install chromium && npm test`
+Expected: PASS (1 test). If the wheel handler needs a different target, adjust the selector to the element bound in `onWheel` setup.
+
+- [ ] **Step 4: Document the tier**
+
+`simulator/e2e/README.md`: prerequisites (`npm install`, `npx playwright install chromium`), how `webServer` boots uvicorn, and `npm test`.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add simulator/e2e
+git commit -m "test(e2e): Playwright tier asserts altitude lock + matching morph"
+```
+
+---
+
+### Task 9: Regenerate sample media + manifest, full suite green
+
+Bake the 154 morphs into `simulator/sample_media`, rebuild the manifest, and run the entire pytest suite + the E2E spec so the shipped sample media matches the new schema.
+
+**Files:**
+- Modify (generated): `simulator/sample_media/manifest.json`, `simulator/sample_media/transitions/*.mp4`
+
+- [ ] **Step 1: Rebuild media + manifest**
+
+Run: `cd simulator && python build_pool_manifest.py --media` (or the script's generate+manifest entrypoint — confirm its CLI flags) to bake morphs and rewrite `manifest.json`.
+Expected: `sample_media/transitions/` contains 154 files; `manifest.json` ring has 154 transition entries.
+
+- [ ] **Step 2: Verify every manifest transition file exists**
+
+```python
+# one-off check (or add as tests/test_catalog_integrity.py case)
+import json, pathlib
+m = json.load(open("simulator/sample_media/manifest.json"))
+base = pathlib.Path("simulator/sample_media")
+missing = [t["file"] for t in m["ring"]["transitions"] if not (base / t["file"]).exists()]
+assert not missing, missing
+```
+
+- [ ] **Step 3: Run the full suite**
+
+Run: `pytest -q`
+Expected: PASS (all existing + new tests; ~270+).
+
+- [ ] **Step 4: Run the E2E spec against the regenerated media**
+
+Run: `cd simulator/e2e && npm test`
+Expected: PASS
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add simulator/sample_media
+git commit -m "chore(media): regenerate 154 clip-pair morphs + manifest"
+```
+
+---
+
+## Self-Review
+
+**Spec coverage (operator directives):**
+- "Choose which clip plays in the next altitude *before* transitioning" → Task 4 (`resolve_move` picks dst then morph) + Task 6 (server draws picks before resolving).
+- "Play the appropriate morph footage" → Task 7 (renderer plays the resolved `step.file`).
+- "Morph footage for all transitions between all videos in adjacent altitudes" → Tasks 1–2 (manifest + bake 154, both directions) + Task 9 (regenerate).
+- "Video must not change after we've zoomed to a new altitude" / "lock per altitude until the altitude is changed" → Task 7 (delete secondary swap; lock `activeClipId`; reload only on altitude change) + Task 8 (E2E asserts stability while parked).
+- "Good transition for every video combination, in and out" → both directions baked (Task 1/2), reverse via explicit `.rev` entries (Task 3/4), E2E covers in + out (extend Task 8 spec with a zoom-out case if desired).
+- Multi-altitude jump chains through each altitude → Task 4 (`resolve_move` threads src→dst per step) + Task 5 (fast spin plays the chain quickly).
+
+**Placeholder scan:** No TBD/TODO/"handle edge cases" — every code step shows real code; tests show real assertions.
+
+**Type consistency:** `Transition(from_clip, to_clip, file, model)` (T3) used by `morph_for` (T3), `load_ring` (T3), `resolve_move` (T4), `resolved_move_to_dict` (T6). `MorphStep`/`ResolvedMove` fields (T4) match the serializer (T6) and the renderer's `step.{from_clip,to_clip,file,to_index,blended}` + `move.target_clip_id` (T7). `morphByPair` key `"from→to"` consistent in build (T7 S1) and lookup (T7 S4).
+
+**Open items (resolved at the review gate by the operator):**
+1. **Storage/repo weight:** ✅ Commit the 154 short mp4s into `sample_media` (extends the existing precedent of committing the 5 + bases).
+2. **`build_pool_manifest.py` CLI:** ✅ Approach approved; confirm the actual entrypoint flag during execution (Task 9 Step 1).
+3. **Zoom-out E2E:** ✅ Added — Task 8 now covers zoom-in + lock **and** a zoom-out (`.rev` morph) + lock case.

sessions/0021/SESSION-0021.0-TRANSCRIPT-2026-06-26T08-12--2026-06-26T08-20.md

@@ -0,0 +1,88 @@
+# Session 0021.0 — Transcript
+
+> App: human-experience-filter-art
+> Start: 2026-06-26T08-12 (PST)
+> End: 2026-06-26T08-20 (PST)
+> Type: executing-plans (operator-driven hotfix/revision of session 0020's audio feature)
+> Posture: yolo
+> Claude-Session: e0cc053a-41fa-416d-a4f5-493f14984e75
+> Status: FINALIZED
+
+## Launch prompt
+
+> Show video unchecked doesn't turn off the video. Make "show video" just "Video"
+> and have a toggle like "Dev Mode" has. I can't hear any audio when "soundtrack
+> (follows altitude)" is selected. Let's just have Audio as off/on like Video for
+> now and get rid of white noise.
+
+## Pre-state
+
+- Session 0020 had just merged the audio feature to `main` (Visual×Audio split,
+  per-altitude soundtracks, pink white-noise, A/B crossfade). The operator tested it
+  live and reported three issues.
+
+## Session arc
+
+1. **Diagnosis (the key work).** Both reported bugs were reproduced *only* in the
+   operator's real browser — neither appeared in headless Chromium **or** WebKit
+   (installed `playwright install webkit` to test Safari's engine). Root causes:
+   - **Video-off doesn't blank:** `#vid` (`<video>`) and `#paint` (WebGL `<canvas>`)
+     are GPU-composited layers; the `#black` cover had *auto* z-index, so on a real
+     GPU (Safari/Chrome) the video layer can composite *above* it despite DOM order.
+     Headless software-raster hides this.
+   - **No soundtrack audio:** real Safari/iOS unlocks an `<audio>` element only when
+     `play()` is called *synchronously inside* the user gesture; the 0020 gesture
+     played in an async continuation (after `await fetch`), which Chrome allows but
+     Safari blocks. Headless WebKit relaxes autoplay, so it passed.
+   This is the session's main lesson: **Playwright headless relaxes both GPU
+   compositing and autoplay**, so the 0020 E2E couldn't have caught either — real
+   device / by-eye review is required.
+2. **Fixes (branch `session-0021`):**
+   - **Video** + **Audio** are now Dev-Mode-style on/off toggles (`.dev-switch`),
+     wired on `change`. Audio on → soundtrack; **white-noise deferred** (removed from
+     the live control; `AUDIO_SOURCES={off,soundtrack}`; the pure pink-noise
+     machinery + tests stay for later).
+   - Video-off: `.black` gets `z-index:50` + `translateZ(0)` (own layer) **and** the
+     video layers are set `opacity:0` on video-off (belt-and-suspenders blanking).
+   - Safari audio: the tap-to-start gesture now primes both A/B `<audio>` elements
+     **synchronously in-gesture** (set src, vol 0, `play().then(pause)`), unlocking
+     the later async crossfades.
+   - Server: `player/audio.py` resolver + `controls.py`/`state.py` + `/api/alteration`
+     drop white-noise; `build_audio_media.py` stops emitting the noise bed.
+3. **Verify + ship.** Updated unit/contract/E2E tests; rewrote the 3 E2E for the new
+   toggles (click the visible `.dev-switch-track`; wait for the opacity transition).
+   **288 passed, 2 skipped.** Re-verified in **both Chromium and WebKit**: Audio toggle
+   plays `cosmos/pillars.loop.mp3`, video-off sets vid+paint opacity 0 with `#black`
+   shown, zero JS errors; screenshotted the new toggle UI. Merged `session-0021` →
+   `main` and pushed. (Also untracked a stray `docs/.threads/*.json` editor artifact
+   swept in by `git add -A`, and gitignored `.threads/`.)
+
+## Deferred decisions
+
+_No low-confidence calls. All three changes were explicit operator requests; the
+root-cause fixes (GPU z-index/layer-hide; Safari in-gesture unlock) are the standard
+remedies for these well-known browser behaviors._
+
+## Cut state
+
+- `main` @ `fddb6d6` (merge of session-0021), clean, pushed.
+- **288 tests + 3 Playwright E2E pass** (2 skipped: opt-in media integration).
+- White-noise is deferred, not deleted: `tools/pipeline/audio_ops.white_noise_args` +
+  `audio_run.generate_white_noise` + their tests remain; only the live control + the
+  build-script emission were removed.
+- **Unvalidated by this session:** real-device audio (Safari autoplay) and real-GPU
+  video-off — headless can't exercise either; needs the operator's by-ear/by-eye pass.
+
+## Operator plate
+
+- Video + Audio are simple on/off toggles (Dev-Mode style). Audio on = the current
+  altitude's soundtrack. The two real-browser bugs should now be fixed — but please
+  confirm on a real device (especially iPad/Safari).
+- Deferred: white-noise (easy to re-add as a 3rd Audio position), the per-altitude
+  music layer, the networked-control-surface build, Pi renderer.
+
+## Next /goal
+
+```
+/goal by-ear/by-eye review the audio + Video/Audio toggles on a REAL device (esp. iPad/Safari — headless can't validate Safari autoplay or GPU compositing), then source/compose the deferred per-altitude music layer per docs/audio-candidate-pool.md (or re-enable white-noise as a 3rd Audio position if wanted)
+```

sessions/0022/SESSION-0022.0-TRANSCRIPT-2026-06-26T08-40--2026-06-26T08-50.md

@@ -0,0 +1,79 @@
+# Session 0022.0 — Transcript
+
+> App: human-experience-filter-art
+> Start: 2026-06-26T08-40 (PST)
+> End: 2026-06-26T08-50 (PST)
+> Type: executing-plans (operator-driven follow-up to the audio feature)
+> Posture: yolo
+> Claude-Session: e0cc053a-41fa-416d-a4f5-493f14984e75
+> Status: FINALIZED
+
+## Launch prompt
+
+> (1) "It shouldn't say 'Tap to Start Sound'… it can start with both sound and video
+> off but immediately go to the app. We should have a 'Loading Universe…' loading
+> screen until all media has been downloaded and the experience is ready to run."
+> (2) "I still can't hear the sound, even in private mode."
+> (3) "The first time video is turned on, also turn on audio. If audio is turned on
+> before video after the app loads, just audio should turn on."
+
+## Pre-state
+
+- Sessions 0020/0021 had shipped the audio feature + a 0021 "Safari fix" (tap-to-start
+  overlay that primed A/B `<audio>` elements). The operator reported audio STILL
+  silent on their real browser (even in private mode), plus the UX requests above.
+
+## Session arc
+
+1. **Why the 0021 fix failed.** It primed *srcless* A/B elements in the tap gesture
+   and played the real audio in an *async continuation* (after `await fetch`). Safari
+   unlocks an element only when `play()` runs **synchronously inside** the gesture and
+   on an element **with a src** — so neither condition was met. Headless WebKit relaxes
+   autoplay, which is why automated tests never caught it.
+2. **Redesign (client-only, branch `session-0022`):**
+   - **Single `<audio id="aud">`** element (dropped A/B). It's played **synchronously
+     inside the toggle's own `change` handler** — the canonical Safari unlock. Altitude
+     changes reuse the now-unlocked element with a brief fade-swap.
+   - **"Loading Universe…" splash** (`#loading`, in the HTML so it shows pre-JS): `main()`
+     now `await`s `preloadAllMedia()` (driving a progress bar), then `hideLoading()`.
+     Replaces the tap-to-start wall.
+   - **Both toggles default OFF** (black + silent at start) — no autoplay needed until a
+     toggle is flipped.
+   - **First Video-on couples Audio:** the Video `change` handler, on the first on,
+     sets `#audio` checked and plays — in the same gesture (so it unlocks on Safari).
+     Audio toggled on first stays audio-only.
+   - Server contract unchanged (`{off,soundtrack}`); the client now drives playback
+     directly from the ring's `scale.audio`, ignoring `render.audio`.
+3. **Verify + ship.** Rewrote the 5 E2E for the new flow (single `#aud`, no gesture,
+   loading wait, the coupling, video-off blanking). Caught a test bug — `#black.hidden`
+   is `display:none`, so `wait_for_selector` default (visible) timed out; switched to
+   `state="attached"`. **290 passed, 2 skipped; 5 E2E pass.** Verified in headless
+   **Chromium AND WebKit**: first-Video-on couples audio, soundtrack plays, video shows,
+   zero JS errors; screenshotted the splash + running app. Merged to `main`.
+
+## Deferred decisions
+
+_No low-confidence calls — all three were explicit operator requests. The
+single-element synchronous-in-gesture play is the standard Safari remedy._
+
+## Cut state
+
+- `main` @ `4ac39c9`, clean, pushed. 290 tests + 5 Playwright E2E pass.
+- **Honest caveat — still unverifiable headlessly:** every engine Playwright ships
+  (Chromium, WebKit) relaxes autoplay, so I cannot *prove* real-Safari/iOS now plays.
+  The fix is the canonical pattern (sync `play()` in the gesture, real src) and is a
+  genuine change from 0021's broken approach — but it needs the operator's real-device ear.
+
+## Operator plate
+
+- No tap wall: "Loading Universe…" → app with both toggles off (black/silent). Flip
+  **Video** → video + audio together; flip **Audio** alone → audio only.
+- If sound is STILL silent on the real device, that points to something beyond autoplay
+  (codec/MIME, file, or element error) — next session should capture `aud.error` and the
+  exact browser.
+
+## Next /goal
+
+```
+/goal confirm on a REAL device (esp. iPad/Safari) that audio is now audible when Video/Audio is toggled on and the "Loading Universe…" → app flow feels right; if still silent, capture aud.error + the exact browser. Then the deferred per-altitude music layer per docs/audio-candidate-pool.md
+```

sessions/sessions.json

@@ -58,5 +58,11 @@
   },
   "0020": {
     "title": ""
+  },
+  "0021": {
+    "title": ""
+  },
+  "0022": {
+    "title": ""
   }
 }

simulator/static/app.js

@@ -506,6 +506,10 @@ function controls() {
   return {
     visual: $("visual").checked ? "on" : "off",
     audio: $("audio").checked ? "soundtrack" : "off",
+    // Back-compat: a server process predating the visual/audio split still requires
+    // a 7-way `content` and would 422 the new payload. Send both — the current
+    // server ignores `content`, an old one ignores visual/audio.
+    content: $("visual").checked ? "video" : "off",
     left: +$("left").value, right: +$("right").value,
     dark: mood < 0 ? -mood : 0, light: mood > 0 ? mood : 0,
     volume: 2, brightness: 2,
@@ -522,7 +526,11 @@ async function update() {
   if (!resp.ok) { readout.textContent = "invalid: " + resp.status; return; }
   const data = await resp.json();
   readout.textContent = JSON.stringify(data, null, 2);
-  if (!data.render.video.shown) {
+  // Tolerate a stale server that still returns {content:{video}} instead of the
+  // {render:{video:{shown}}} (visual/audio-split) shape, so video works either way.
+  const videoShown = data.render ? !!(data.render.video && data.render.video.shown)
+                                 : !!(data.content && data.content.video);
+  if (!videoShown) {
     // Blank the screen. Cover with #black AND hide the video layers themselves —
     // the <video>/<canvas> are GPU-composited and can otherwise show through the
     // overlay on a real GPU (Safari/Chrome).
@@ -920,8 +928,33 @@ function devLiveReload() {
 // (e.g. on an altitude change). audio on = the current scale's soundtrack.
 const aud = $("aud");
 let audUrl = null;                      // soundtrack url currently loaded (null = silent)
+let audLastErr = "";                    // last play() rejection / element error (for the readout)
 const FADE_MS = 500;
 
+// --- Live audio status readout (diagnostic) — so a "no sound" report is legible ---
+const AUD_ERR = ["", "aborted", "network", "decode", "format-not-supported"];
+function audioStatusText() {
+  if (!$("audio").checked) return "audio: off";
+  const s = ring && ring.scales[ringIndex];
+  const url = soundtrackUrl();
+  const head = `ON · scale=${s ? s.id : "?"} · ring=${serverRing ? "server" : "SYNTH"} · url=${url || "NONE"}`;
+  if (!url) return "audio: " + head + " ← no soundtrack URL for this scale";
+  if (aud.error) return `audio: ${head} · MEDIA ERROR ${aud.error.code} (${AUD_ERR[aud.error.code] || "?"})`;
+  if (audLastErr) return `audio: ${head} · ${audLastErr}`;
+  if (aud.paused) return `audio: ${head} · PAUSED rs=${aud.readyState}`;
+  return `audio: ${head} · ▶ ${aud.currentTime.toFixed(1)}s vol=${Math.round(aud.volume * 100)}% rs=${aud.readyState}`;
+}
+function updateAudioStatus() {
+  const el = $("audio-status");
+  if (!el) return;
+  el.textContent = audioStatusText();
+  const playing = $("audio").checked && !!soundtrackUrl() && !aud.paused && !aud.error && !audLastErr;
+  el.classList.toggle("playing", playing);
+  el.classList.toggle("blocked", $("audio").checked && (!soundtrackUrl() || !!aud.error || !!audLastErr));
+}
+aud.addEventListener("error", updateAudioStatus);
+setInterval(updateAudioStatus, 400);
+
 function fadeVolume(el, to, ms, done) {
   // setInterval (not requestAnimationFrame): rAF throttles/pauses when the tab is
   // backgrounded, which would stall the gain ramp; a timer fires regardless.
@@ -935,10 +968,25 @@ function fadeVolume(el, to, ms, done) {
   }, 30);
 }
 
-// The current altitude's soundtrack url (the ring carries each scale's `audio`).
+// Fallback per-scale soundtrack paths, used when the ring from /api/ring lacks the
+// `audio` field (e.g. a server process started before the audio field existed).
+// Mirrors simulator/build_pool_manifest.py SCALE_AUDIO — the 5 scales + files are
+// fixed, committed facts, so this keeps audio working without a server restart.
+const SCALE_AUDIO_FALLBACK = {
+  cosmos: "cosmos/pillars.loop.mp3",
+  orbit: "orbit/spaceamb.loop.mp3",
+  coast: "coast/waves.loop.mp3",
+  reef: "reef/soundscape.loop.mp3",
+  abyss: "abyss/whale.loop.mp3",
+};
+
+// The current altitude's soundtrack url: the ring's `audio` field, else the
+// scale-id fallback above.
 function soundtrackUrl() {
   const s = ring && ring.scales[ringIndex];
-  return s && s.audio ? "/media/audio/" + s.audio : null;
+  if (!s) return null;
+  const a = s.audio || SCALE_AUDIO_FALLBACK[s.id];
+  return a ? "/media/audio/" + a : null;
 }
 
 // Load `url` into the single element and fade it in. Call this SYNCHRONOUSLY from
@@ -947,8 +995,12 @@ function soundtrackUrl() {
 function playUrl(url) {
   aud.src = mediaUrl(url);
   aud.volume = 0;
+  audLastErr = "";
   const pr = aud.play();
-  if (pr) pr.catch(() => {});
+  if (pr) {
+    pr.then(() => { audLastErr = ""; updateAudioStatus(); })
+      .catch((e) => { audLastErr = "play BLOCKED: " + ((e && e.name) || e); updateAudioStatus(); });
+  }
   fadeVolume(aud, 1, FADE_MS);
 }
 

simulator/static/index.html

@@ -66,6 +66,15 @@
       </label>
 
       <div id="dev-panel" class="dev-panel hidden">
+        <fieldset>
+          <legend>Audio diagnostics</legend>
+          <div id="audio-status" class="audio-status">audio: off</div>
+          <p class="hint">Native player — tests the soundtrack file directly (bypasses
+            all app code). If it plays here but the Audio toggle is silent, it's a
+            code/autoplay issue, not the file.</p>
+          <audio id="aud-test" controls preload="auto" src="/media/audio/cosmos/pillars.loop.mp3" style="width:100%"></audio>
+        </fieldset>
+
         <fieldset>
           <legend>Pool — pick a clip</legend>
           <select id="pool-select" aria-label="Choose a clip from this altitude's pool"></select>

simulator/static/style.css

@@ -49,6 +49,10 @@ main { display: flex; gap: 1rem; padding: 1rem; flex-wrap: wrap; align-items: fl
 .hidden { display: none; }
 /* Stack the two Output toggles (Video / Audio) with a little breathing room. */
 .dev-switch + .dev-switch { margin-top: 0.45rem; }
+/* Live audio status readout (diagnostic) — turns green when actually playing. */
+.audio-status { margin-top: 0.5rem; font: 11px/1.4 monospace; color: #9ab; }
+.audio-status.playing { color: #4e9; }
+.audio-status.blocked { color: #f97; }
 .panel { flex: 0 0 280px; display: flex; flex-direction: column; gap: 0.8rem;
          max-height: calc(100vh - 2rem); overflow-y: auto;
          position: sticky; top: 1rem; }

tests/test_e2e_audio.py

@@ -101,6 +101,26 @@ def test_audio_before_video_stays_audio_only(page):
     page.wait_for_selector("#black:not(.hidden)")       # still blanked
 
 
+def test_audio_then_video_leaves_both_on(page):
+    _toggle(page, "audio")                             # audio first
+    page.wait_for_function("!document.getElementById('aud').paused")
+    _toggle(page, "visual")                            # then video
+    page.wait_for_selector("#black.hidden", state="attached")   # video showing
+    assert page.is_checked("#audio") is True
+    assert page.evaluate("!document.getElementById('aud').paused") is True   # audio still plays
+
+
+def test_soundtrack_fallback_when_ring_lacks_audio(page):
+    # simulate a stale server whose /api/ring omits the per-scale `audio` field;
+    # the client falls back to the scale-id soundtrack map so audio still plays
+    page.evaluate("ring.scales.forEach(s => { delete s.audio; })")
+    _toggle(page, "audio")
+    page.wait_for_function(
+        "(() => { const a = document.getElementById('aud');"
+        " return a.src.includes('/media/audio/cosmos/') && !a.paused; })()"
+    )
+
+
 def test_video_off_blanks_after_being_on(page):
     _toggle(page, "visual")                            # on
     page.wait_for_selector("#black.hidden", state="attached")