.gitignore

@@ -5,5 +5,6 @@ __pycache__/
 media/
 .superpowers/
 *.egg-info/
-# Simulator sample media (look-tuning only; populate via setup_sample_media.py)
-simulator/sample_media/forest/*.mp4
+# Simulator sample media (look-tuning only; populate via setup_sample_media.py
+# / setup_scales_media.py). All scale + transition binaries are gitignored.
+simulator/sample_media/**/*.mp4

docs/ROADMAP.md

@@ -139,6 +139,23 @@ Design:
 plan:
 [`2026-06-07-reconciled-simulator-alteration-slice.md`](./superpowers/plans/2026-06-07-reconciled-simulator-alteration-slice.md).
 
+**Slice 3 — scale-ring navigation (simulator) ✅ Done.** Merged to `main`
+(session 0011). Adds the **endless rotary-encoder** control — *relative* (vs the
+absolute 0–4 experience knobs) — that walks a **closed ring** of neutral
+"scales of nature" clips, with placeholder AI zoom/warp **transitions** between
+adjacent scales and a small→large **wrap** (the infinite-zoom payoff, scales
+design §3). The navigation math is canonical Python (`player/ring.py`:
+`ScaleRing` + `advance_ring`, one transition clip per edge, played forward
+inward / reversed outward); the sim exposes `GET /api/ring` + `POST
+/api/ring/advance` and the browser only plays the returned transition(s) then
+settles on the target scale, keeping the live knob alteration on top. Two cheap
+**true-PD** scales were added so the ring is demonstrable — `cosmos` (NASA/Hubble)
+and `abyss` (NOAA Ocean Exploration), provenance recorded in the manifest, bytes
+generated as labelled placeholders by `simulator/setup_scales_media.py`. The
+expensive real multi-strength flow-stabilized Right re-bake is **deferred** (new
+scales carry a raw base only) until the ring is liked. Plan:
+[`2026-06-07-scale-ring-navigation.md`](./superpowers/plans/2026-06-07-scale-ring-navigation.md).
+
 **Remaining slices (not started):**
 
 - **Runtime renderer** — drive the single panoramic projector via mpv/ffmpeg;
@@ -152,10 +169,9 @@ plan:
 - **Offline v2v variant pipeline** — author the pre-baked Right restyle variants
   via the local flow-stabilized SD pipeline (now ~free, not a paid API — see the
   scales-library/right-axis design §1/§4); a real multi-strength flow-stabilized
-  re-bake per base clip + the multilingual label/string tables + TTS.
-- **Scale-ring navigation** — the endless rotary encoder + short pre-baked AI
-  zoom/warp transitions between neutral "scales of nature" clips on a closed ring
-  (scales-library design §3); a new control + offline pipeline element.
+  re-bake per base clip + the multilingual label/string tables + TTS. The
+  **scale-ring transitions** (forward/reverse per-edge morphs) are part of this
+  offline pipeline too — the simulator currently uses placeholders.
 - **Catalog model changes** — audio *source* + "neutral base" vs "altered
   variant" flag (sub-project 2 territory, design §13).
 

docs/USER_GUIDE.md

@@ -298,12 +298,16 @@ piece moved from *selecting* clips to *altering* them.)
 **One-time setup — populate the sample footage** (look-tuning only; not shipped
 content):
 
-    python simulator/setup_sample_media.py
+    python simulator/setup_sample_media.py    # the forest scale (real POC base + Right variants)
+    python simulator/setup_scales_media.py    # the cosmos + abyss scales + ring transitions
 
-This copies the session-0008 POC artifacts (`~/hef-poc/out/`) into
-`simulator/sample_media/forest/` — the neutral base clip and the real
+`setup_sample_media.py` copies the session-0008 POC artifacts (`~/hef-poc/out/`)
+into `simulator/sample_media/forest/` — the neutral base clip and the real
 flow-stabilized Right restyle — and generates placeholder intermediate Right
-strengths. The `.mp4` binaries are gitignored.
+strengths. `setup_scales_media.py` makes the scale **ring** demonstrable: cheap
+synthetic placeholder bases for the two true-PD scales (`cosmos` = NASA/Hubble,
+`abyss` = NOAA Ocean Exploration) plus the per-edge zoom/warp transition clips.
+The `.mp4` binaries are gitignored.
 
 **Run it (Docker):**
 
@@ -320,6 +324,13 @@ then open http://localhost:8000.
 
 - **Content dial** — picks audio/video channel; "off" and audio-only positions go
   to black walls.
+- **Scale ring (endless encoder)** — `⊖ out` / `in ⊕` (or scroll the stage) walk a
+  *closed ring* of neutral "scales of nature" clips — cosmos → forest → abyss and
+  back around (diving past the smallest **wraps** to the largest). It is *relative*
+  (an endless encoder), distinct from the absolute 0–4 knobs: each step plays a
+  short placeholder zoom/warp **transition**, then settles on the next scale, with
+  the current knob alteration still applied. The current scale is named beside the
+  buttons (`name (i/N)`).
 - **Four experience knobs (0–4):**
   - **Dark / Light** — a live runtime color grade (cool/dark ↔ warm/bright; equal
     or zero = the raw footage).

docs/superpowers/plans/2026-06-07-scale-ring-navigation.md

@@ -0,0 +1,97 @@
+# Scale-Ring Navigation (Simulator) — Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:executing-plans or
+> superpowers:subagent-driven-development to implement task-by-task. Steps use
+> checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Add scale-ring navigation to the simulator — an endless rotary-encoder
+control (relative, vs the absolute 0–4 experience knobs) that walks a *closed
+ring* of neutral "scales of nature" clips, with placeholder AI zoom/warp
+transitions between adjacent scales. Add 1–2 cheap, true-PD neutral base clips
+(NASA/Hubble cosmos + NOAA Ocean Exploration deep sea) so the ring is
+demonstrable. **Defer** the expensive real multi-strength flow-stabilized Right
+re-bake until the ring is liked; keep deferring the Pi renderer + serial/firmware.
+
+**Spec:** `docs/superpowers/specs/2026-06-07-scales-library-and-right-axis-pipeline-design.md` §3 (scale navigation & zoom transitions), §2 (scales library), §2.1 (strict-PD sourcing map).
+
+**Architecture:** Python stays the single source of truth. The ring *navigation
+math* — step, wrap, which transition clip to play and in which direction — lives
+in a new canonical pure module `player/ring.py` (mirrors `player/content.py` /
+`player/alteration.py`: frozen dataclasses, pure functions). The simulator's data
+layer (`simulator/clips.py`) parses a `ring` section of the manifest into the
+ring types; the API exposes the ring and a stateless `advance` move; the browser
+holds the current ring index and only *renders* (plays the returned transition
+file, then the target scale's clip, with the existing per-knob alteration on top).
+
+**Ordering convention (canonical):** ring index 0 = the *largest* scale (cosmos);
+increasing index zooms **inward** toward the smallest. `+1` detent = zoom in,
+`-1` = zoom out — both wrap (past the smallest wraps to the largest, the
+infinite-zoom payoff, §3). Edge `i` connects `scales[i] → scales[(i+1) % N]`; the
+last edge is the small→large wrap seam. One transition clip per edge plays
+**forward** when zooming inward and **reversed** when zooming outward, so N scales
+need only N transition clips (§3: "one clip per ring edge").
+
+**Deferral, made explicit:** the new cosmos/abyss scale clips carry a raw base
+only (no pre-baked Right variants); the `Clip` model already falls back any
+unauthored strength to the raw base, so Right on a new scale is a no-op until the
+multi-strength flow-stabilized re-bake happens (deliberately deferred). Forest
+keeps its existing POC variants.
+
+**Tech Stack:** Python 3.13, FastAPI + pydantic, pytest, frozen dataclasses;
+vanilla JS + CSS/SVG for the browser; ffmpeg (system or `imageio-ffmpeg`) for
+placeholder media.
+
+---
+
+## File Structure
+
+**Engine (create):**
+- `player/ring.py` — `Scale`, `Transition`, `ScaleRing`, `RingMove`,
+  `TransitionStep`, `scale_at`, `advance_ring`. Pure logic, no I/O/JSON.
+
+**Simulator (modify):**
+- `simulator/clips.py` — add `load_ring(manifest)` building a `ScaleRing` from the
+  manifest `ring` section + `ring_to_dict` / `ring_move_to_dict` serializers.
+- `simulator/app.py` — `GET /api/ring`, `POST /api/ring/advance`.
+- `simulator/static/{index.html,app.js,style.css}` — endless-encoder control
+  (zoom-in/zoom-out buttons + mouse-wheel on the stage), current-scale readout,
+  multi-clip active-clip selection, transition playback.
+- `simulator/sample_media/manifest.json` (committed) — add cosmos + abyss clips
+  and the `ring` section; media binaries stay gitignored.
+- `simulator/setup_sample_media.py` (or sibling) — generate cheap cosmos/abyss
+  base placeholders + per-edge transition placeholders (ffmpeg); record true-PD
+  provenance in the manifest. Real PD fetch is a best-effort `--fetch` bonus.
+
+**Tests (create/extend):**
+- `tests/test_player_ring.py` (create) — ring navigation logic (step, chain, wrap,
+  direction/reverse, degenerate N≤1).
+- `tests/test_clips.py` (extend) — `load_ring`, serializers.
+- `tests/test_simulator_api.py` (extend) — `/api/ring`, `/api/ring/advance`.
+
+**Docs:**
+- `docs/ROADMAP.md` — scale-ring status.
+- `docs/USER_GUIDE.md` — simulator "scale ring" gesture (if present).
+
+---
+
+## Task 1: Engine — `player/ring.py` (pure ring navigation)
+- [ ] TDD `Scale`/`Transition`/`ScaleRing` construction + validation (N edges for N scales; ≥1 scale; degenerate N≤1 ring).
+- [ ] TDD `scale_at` (mod indexing) and `advance_ring(ring, from_index, delta)` → `RingMove` (to_index by mod; per-unit `TransitionStep` list; `reversed` on outward; `wrapped` flag on crossing the seam; chained steps for |delta|>1).
+
+## Task 2: Simulator data layer — `load_ring` + serializers
+- [ ] TDD `load_ring(manifest)` parsing the `ring` section into a `ScaleRing`.
+- [ ] TDD `ring_to_dict` / `ring_move_to_dict`.
+
+## Task 3: API — `/api/ring`, `/api/ring/advance`
+- [ ] TDD `GET /api/ring` (scales + transitions, with each scale's title) and `POST /api/ring/advance` (validates from_index/delta; returns the move + target clip_id).
+
+## Task 4: Media — cosmos + abyss bases + transitions; manifest
+- [ ] Add cosmos + abyss clips and the `ring` section to the committed manifest with true-PD provenance.
+- [ ] Extend the media-setup script to generate cheap base + transition placeholders (and optional real PD fetch).
+
+## Task 5: Frontend — endless encoder + multi-clip + transition playback
+- [ ] Active-clip selection by ring index; zoom-in/out buttons + wheel; current-scale readout; play returned transition file(s), then settle on target clip; keep live alteration on top.
+
+## Task 6: Verify + docs
+- [ ] Full `pytest -q` green; boot the sim and exercise the ring by eye/screenshot.
+- [ ] Update ROADMAP / USER_GUIDE.

player/ring.py

@@ -0,0 +1,152 @@
+"""Scale-ring navigation: the endless-encoder closed loop of nature scales (§3).
+
+Design: docs/superpowers/specs/2026-06-07-scales-library-and-right-axis-pipeline-
+design.md §3 (scale navigation & zoom transitions).
+
+The scales-of-nature library is navigated as a CLOSED RING, not a line. A
+dedicated endless rotary encoder — relative, vs the absolute 0..4 experience
+knobs — walks the ring one step per detent; diving past the smallest scale wraps
+around to the largest (the infinite-zoom payoff). Between each adjacent pair of
+scales a short pre-baked AI zoom/warp transition plays.
+
+This is the canonical navigation engine (Python-canonical, shared with the Pi
+player/firmware); the simulator browser only renders what `advance_ring` returns.
+
+Ordering convention:
+  - index 0 = the LARGEST scale (cosmos); increasing index zooms INWARD toward
+    the smallest.
+  - +1 detent zooms in, -1 zooms out; BOTH wrap (past the smallest wraps to the
+    largest, and vice versa).
+  - edge i connects scales[i] -> scales[(i+1) % N]; the last edge is the
+    small->large wrap seam. One transition clip per edge plays FORWARD when
+    zooming inward and REVERSED when zooming outward, so N scales need only N
+    transition clips.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+class RingError(ValueError):
+    """Raised when a ScaleRing is structurally invalid."""
+
+
+@dataclass(frozen=True)
+class Scale:
+    """A node on the ring: a scale of nature and the base clip it plays."""
+
+    id: str
+    clip_id: str
+
+
+@dataclass(frozen=True)
+class Transition:
+    """A pre-baked zoom/warp morph along ONE ring edge.
+
+    `file` plays FORWARD when zooming inward (scales[i] -> scales[i+1] in ring
+    order); the renderer reverses it for the outward direction, so one clip
+    covers both directions of an edge.
+    """
+
+    file: str
+    model: str = ""
+
+
+@dataclass(frozen=True)
+class ScaleRing:
+    """A closed ring of scales joined by per-edge transitions.
+
+    Invariant: a ring of N>=2 scales has exactly N transitions (one per edge,
+    including the small->large wrap seam). A degenerate single-scale ring has no
+    edges. An empty ring is rejected.
+    """
+
+    scales: tuple[Scale, ...]
+    transitions: tuple[Transition, ...]
+
+    def __post_init__(self) -> None:
+        n = len(self.scales)
+        if n == 0:
+            raise RingError("a ScaleRing needs at least one scale")
+        expected = 0 if n == 1 else n
+        if len(self.transitions) != expected:
+            raise RingError(
+                f"a {n}-scale ring needs {expected} transitions, "
+                f"got {len(self.transitions)}"
+            )
+
+    def __len__(self) -> int:
+        return len(self.scales)
+
+
+@dataclass(frozen=True)
+class TransitionStep:
+    """One transition to play during a move: which edge clip, in which direction,
+    and the scale index it lands on."""
+
+    edge: int
+    reversed: bool
+    file: str
+    to_index: int
+
+
+@dataclass(frozen=True)
+class RingMove:
+    """The result of advancing the encoder: where you end up and the ordered
+    transitions to play getting there (chained for a multi-detent spin)."""
+
+    from_index: int
+    to_index: int
+    steps: tuple[TransitionStep, ...]
+    wrapped: bool
+
+
+def scale_at(ring: ScaleRing, index: int) -> Scale:
+    """The scale at `index`, taken modulo the ring length (wraps both ways)."""
+    return ring.scales[index % len(ring)]
+
+
+def advance_ring(ring: ScaleRing, from_index: int, delta: int) -> RingMove:
+    """Walk the endless encoder `delta` detents from `from_index` (signed).
+
+    Returns a `RingMove` with the landing index and the ordered `TransitionStep`s
+    to play. Inward steps (+) play edge i forward; outward steps (-) play the
+    crossed edge reversed. `wrapped` is True if any step crossed the small<->large
+    seam. A degenerate single-scale ring (or delta 0) is a no-op.
+    """
+    n = len(ring)
+    start = from_index % n
+    if n == 1 or delta == 0:
+        return RingMove(from_index=start, to_index=start, steps=(), wrapped=False)
+
+    direction = 1 if delta > 0 else -1
+    steps: list[TransitionStep] = []
+    wrapped = False
+    index = start
+    for _ in range(abs(delta)):
+        if direction > 0:
+            # zoom inward: edge `index` forward, land at index+1 (mod n)
+            edge = index
+            nxt = (index + 1) % n
+            reversed_ = False
+        else:
+            # zoom outward: cross edge `index-1` reversed, land at index-1 (mod n)
+            edge = (index - 1) % n
+            nxt = (index - 1) % n
+            reversed_ = True
+        if edge == n - 1:
+            wrapped = True
+        steps.append(
+            TransitionStep(
+                edge=edge,
+                reversed=reversed_,
+                file=ring.transitions[edge].file,
+                to_index=nxt,
+            )
+        )
+        index = nxt
+
+    return RingMove(
+        from_index=start, to_index=index, steps=tuple(steps), wrapped=wrapped
+    )

simulator/app.py

@@ -23,7 +23,8 @@ from player.alteration import (
 )
 from player.content import resolve_content
 from player.controls import CONTENT_POSITIONS
-from simulator.clips import load_manifest
+from player.ring import advance_ring
+from simulator.clips import load_manifest, load_ring, ring_move_to_dict, ring_to_dict
 
 STATIC_DIR = Path(__file__).parent / "static"
 MEDIA_DIR = Path(__file__).parent / "sample_media"
@@ -51,6 +52,11 @@ class AlterationRequest(BaseModel):
     calibration: Optional[CalibrationModel] = None
 
 
+class RingAdvanceRequest(BaseModel):
+    from_index: int = 0
+    delta: int
+
+
 def _load_clips(manifest_path: Optional[Path]):
     path = Path(manifest_path) if manifest_path else DEFAULT_MANIFEST
     if path.exists():
@@ -58,9 +64,17 @@ def _load_clips(manifest_path: Optional[Path]):
     return []
 
 
+def _load_ring(manifest_path: Optional[Path]):
+    path = Path(manifest_path) if manifest_path else DEFAULT_MANIFEST
+    if path.exists():
+        return load_ring(path)
+    return None
+
+
 def create_app(manifest_path: Optional[Path] = None) -> FastAPI:
     app = FastAPI(title="HEF Alteration Simulator")
     app.state.clips = _load_clips(manifest_path)
+    app.state.ring = _load_ring(manifest_path)
 
     @app.post("/api/alteration")
     def api_alteration(req: AlterationRequest):
@@ -88,6 +102,19 @@ def create_app(manifest_path: Optional[Path] = None) -> FastAPI:
     def api_clips():
         return {"clips": [c.to_dict() for c in app.state.clips]}
 
+    @app.get("/api/ring")
+    def api_ring():
+        if app.state.ring is None:
+            raise HTTPException(status_code=404, detail="no scale ring in manifest")
+        return ring_to_dict(app.state.ring, app.state.clips)
+
+    @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)
+        return ring_move_to_dict(move, app.state.ring)
+
     if MEDIA_DIR.exists():
         app.mount("/media", StaticFiles(directory=MEDIA_DIR), name="media")
     if STATIC_DIR.exists():

simulator/clips.py

@@ -14,6 +14,8 @@ from dataclasses import dataclass
 from pathlib import Path
 from typing import Any
 
+from player.ring import RingMove, Scale, ScaleRing, Transition, scale_at
+
 
 @dataclass(frozen=True)
 class Clip:
@@ -66,3 +68,58 @@ def load_manifest(path: str | Path) -> list[Clip]:
     path = Path(path)
     data = json.loads(path.read_text())
     return [_clip_from_dict(c) for c in data["clips"]]
+
+
+def load_ring(path: str | Path) -> ScaleRing | None:
+    """Load the optional `ring` section as a `ScaleRing`, or None if absent.
+
+    The ring closes the scales-of-nature library into the navigable loop the
+    endless encoder walks (scales design §3); the navigation math itself lives
+    in player.ring.
+    """
+    path = Path(path)
+    data = json.loads(path.read_text())
+    ring = data.get("ring")
+    if not ring:
+        return None
+    scales = tuple(
+        Scale(id=s["id"], clip_id=s["clip_id"]) for s in ring.get("scales", [])
+    )
+    transitions = tuple(
+        Transition(file=t["file"], model=t.get("model", ""))
+        for t in ring.get("transitions", [])
+    )
+    return ScaleRing(scales=scales, transitions=transitions)
+
+
+def ring_to_dict(ring: ScaleRing, clips: list[Clip]) -> dict:
+    """JSON form of the ring for the API: ordered scales (with their clip title)
+    and the per-edge transitions."""
+    titles = {c.id: c.title for c in clips}
+    return {
+        "scales": [
+            {"id": s.id, "clip_id": s.clip_id, "title": titles.get(s.clip_id, s.id)}
+            for s in ring.scales
+        ],
+        "transitions": [{"file": t.file, "model": t.model} for t in ring.transitions],
+    }
+
+
+def ring_move_to_dict(move: RingMove, ring: ScaleRing) -> dict:
+    """JSON form of an encoder move: the landing scale's clip and the ordered
+    transition clips to play (with direction)."""
+    return {
+        "from_index": move.from_index,
+        "to_index": move.to_index,
+        "wrapped": move.wrapped,
+        "target_clip_id": scale_at(ring, move.to_index).clip_id,
+        "steps": [
+            {
+                "edge": st.edge,
+                "reversed": st.reversed,
+                "file": st.file,
+                "to_index": st.to_index,
+            }
+            for st in move.steps
+        ],
+    }

simulator/sample_media/README.md

@@ -3,10 +3,19 @@
 `manifest.json` is committed; the `.mp4` binaries are **not** (gitignored). They
 are look-tuning samples, not shipped installation content.
 
-Populate them from the session-0008 POC artifacts:
+Populate them in two steps:
 
-    python simulator/setup_sample_media.py
+    python simulator/setup_sample_media.py   # forest (the real POC base + Right variants)
+    python simulator/setup_scales_media.py   # cosmos + abyss scales + ring transitions
 
-This copies `~/hef-poc/out/neutral.mp4` → `forest/base.mp4` and
-`~/hef-poc/out/right_flow.mp4` → `forest/right4.mp4` (the real flow-stabilized
+`setup_sample_media.py` copies `~/hef-poc/out/neutral.mp4` → `forest/base.mp4`
+and `~/hef-poc/out/right_flow.mp4` → `forest/right4.mp4` (the real flow-stabilized
 restyle), and generates placeholder strengths `forest/right1..3.mp4`.
+
+`setup_scales_media.py` makes the scale **ring** demonstrable: cheap synthetic
+placeholder bases for the two true-PD scales — `cosmos/base.mp4` (NASA/Hubble)
+and `abyss/base.mp4` (NOAA Ocean Exploration) — plus the per-edge zoom/warp
+**transition** clips under `transitions/`. The manifest records the real true-PD
+provenance; these bytes are labelled placeholders for tuning ring navigation.
+The new scales carry a raw base only — the expensive multi-strength
+flow-stabilized Right re-bake is **deferred** until the ring is liked.

simulator/sample_media/manifest.json

@@ -1,5 +1,23 @@
 {
   "clips": [
+    {
+      "id": "cosmos",
+      "title": "Cosmos (NASA/Hubble, neutral base)",
+      "base_file": "cosmos/base.mp4",
+      "license": "public-domain (US Gov, 17 U.S.C. §105)",
+      "source": "NASA/Hubble — https://svs.gsfc.nasa.gov/ (true PD; placeholder bytes until ingest)",
+      "right_variants": {},
+      "annotations": [
+        {"key": "detected.galaxy", "box": [0.34, 0.30, 0.30, 0.34], "min_level": 1},
+        {"key": "measure.redshift", "box": [0.36, 0.66, 0.18, 0.08], "min_level": 4}
+      ],
+      "strings": {
+        "en": {
+          "detected.galaxy": "spiral galaxy",
+          "measure.redshift": "z ≈ 0.04"
+        }
+      }
+    },
     {
       "id": "forest",
       "title": "Yosemite Falls (neutral base, POC sample)",
@@ -26,6 +44,36 @@
           "measure.flow_rate": "~2.1 m³/s"
         }
       }
+    },
+    {
+      "id": "abyss",
+      "title": "Deep sea (NOAA Ocean Exploration, neutral base)",
+      "base_file": "abyss/base.mp4",
+      "license": "public-domain (US Gov, 17 U.S.C. §105)",
+      "source": "NOAA Ocean Exploration — https://oceanexplorer.noaa.gov/ (true PD, worldwide; placeholder bytes until ingest)",
+      "right_variants": {},
+      "annotations": [
+        {"key": "detected.organism", "box": [0.40, 0.38, 0.22, 0.26], "min_level": 1},
+        {"key": "measure.depth", "box": [0.06, 0.06, 0.16, 0.08], "min_level": 2}
+      ],
+      "strings": {
+        "en": {
+          "detected.organism": "siphonophore",
+          "measure.depth": "−2,140 m"
+        }
+      }
     }
-  ]
+  ],
+  "ring": {
+    "scales": [
+      {"id": "cosmos", "clip_id": "cosmos"},
+      {"id": "forest", "clip_id": "forest"},
+      {"id": "abyss", "clip_id": "abyss"}
+    ],
+    "transitions": [
+      {"file": "transitions/cosmos-forest.mp4", "model": "placeholder-zoom"},
+      {"file": "transitions/forest-abyss.mp4", "model": "placeholder-zoom"},
+      {"file": "transitions/abyss-cosmos.mp4", "model": "placeholder-zoom"}
+    ]
+  }
 }

simulator/setup_scales_media.py

@@ -0,0 +1,108 @@
+"""Generate cheap placeholder media for the scale RING (scales design §3).
+
+The ring needs >=2 neutral scales to be demonstrable. This script produces
+cheap, offline, synthetic placeholders for the two true-PD scales the ring adds —
+**cosmos** (NASA/Hubble) and **abyss** (NOAA Ocean Exploration) — plus the short
+zoom/warp **transition** clips between adjacent scales. Forest reuses the real
+POC base from `setup_sample_media.py` (or a synthetic placeholder if absent).
+
+This is deliberately the CHEAP path: the manifest records the real true-PD
+provenance (NASA 17 U.S.C. §105 / NOAA PD), but the bytes here are labelled
+synthetic placeholders for look-tuning the ring navigation. The expensive real
+multi-strength flow-stabilized Right re-bake is DEFERRED until the ring is liked,
+so the new scales carry a raw base only (no Right variants).
+
+Usage:  python simulator/setup_scales_media.py
+Requires: ffmpeg on PATH (or `pip install imageio-ffmpeg`).
+"""
+
+from __future__ import annotations
+
+import shutil
+import subprocess
+from pathlib import Path
+
+MEDIA = Path(__file__).parent / "sample_media"
+DUR = 6           # base clip seconds
+XDUR = 1.5        # transition seconds
+SIZE = "1280x720"
+FPS = 25
+
+# Each scale: (dir, base color, on-screen placeholder label).
+SCALES = {
+    "cosmos": ("0x05060f", "COSMOS — NASA/Hubble (PD placeholder)"),
+    "forest": ("0x12301a", "FOREST — Yosemite (POC/placeholder)"),
+    "abyss": ("0x021016", "ABYSS — NOAA Ocean Exploration (PD placeholder)"),
+}
+
+# Ring edges (adjacent pairs + the abyss->cosmos wrap), matching the manifest.
+EDGES = [("cosmos", "forest"), ("forest", "abyss"), ("abyss", "cosmos")]
+
+
+def _ffmpeg() -> str:
+    if shutil.which("ffmpeg"):
+        return "ffmpeg"
+    import imageio_ffmpeg
+    return imageio_ffmpeg.get_ffmpeg_exe()
+
+
+def _run(args: list[str]) -> None:
+    subprocess.run(args, check=True, capture_output=True)
+
+
+def _make_base(ff: str, name: str, color: str, label: str) -> Path:
+    out = MEDIA / name / "base.mp4"
+    out.parent.mkdir(parents=True, exist_ok=True)
+    # A calm solid tint + faint noise grain (reads as stars/particles), with a
+    # placeholder label so it is never mistaken for shipped footage.
+    vf = (
+        "noise=alls=8:allf=t,"
+        "drawtext=text='" + label + "':fontcolor=white@0.55:fontsize=24:"
+        "x=(w-text_w)/2:y=h-48"
+    )
+    _run([
+        ff, "-y", "-f", "lavfi", "-i",
+        f"color=c={color}:s={SIZE}:d={DUR}:r={FPS}",
+        "-vf", vf, "-pix_fmt", "yuv420p", "-an", str(out),
+    ])
+    return out
+
+
+def _make_transition(ff: str, src: str, dst: str) -> Path:
+    a = MEDIA / src / "base.mp4"
+    b = MEDIA / dst / "base.mp4"
+    out = MEDIA / "transitions" / f"{src}-{dst}.mp4"
+    out.parent.mkdir(parents=True, exist_ok=True)
+    w, h = SIZE.split("x")
+    # A placeholder zoom/warp morph: zoom-in crossfade from src into dst. Both
+    # bases are normalized first (size/fps/sar/format) because the real forest
+    # POC base differs in resolution + fps from the synthetic scale placeholders,
+    # and xfade requires identical frame geometry on both inputs.
+    norm = f"trim=0:3,setpts=PTS-STARTPTS,scale={w}:{h},fps={FPS},setsar=1,format=yuv420p"
+    _run([
+        ff, "-y", "-i", str(a), "-i", str(b), "-filter_complex",
+        f"[0:v]{norm}[a];[1:v]{norm}[b];"
+        f"[a][b]xfade=transition=zoomin:duration={XDUR}:offset=0.75,"
+        "format=yuv420p[v]",
+        "-map", "[v]", "-an", str(out),
+    ])
+    return out
+
+
+def main() -> None:
+    ff = _ffmpeg()
+    for name, (color, label) in SCALES.items():
+        base = MEDIA / name / "base.mp4"
+        if name == "forest" and base.exists():
+            print(f"forest/base.mp4 present (real POC base) — keeping")
+            continue
+        _make_base(ff, name, color, label)
+        print(f"generated {name}/base.mp4 (synthetic placeholder)")
+    for src, dst in EDGES:
+        _make_transition(ff, src, dst)
+        print(f"generated transitions/{src}-{dst}.mp4 (placeholder zoom)")
+    print(f"scale-ring media ready in {MEDIA}")
+
+
+if __name__ == "__main__":
+    main()

simulator/static/app.js

@@ -1,19 +1,39 @@
 // Thin renderer: post controls+calibration -> RenderPlan; render grade, Right
-// variant crossfade, and the live Left overlay. All math stays in Python.
+// variant crossfade, and the live Left overlay. All alteration math stays in
+// Python. The scale RING (endless encoder) is navigated via /api/ring/advance —
+// Python owns the step/wrap/transition-selection math; the browser only plays
+// the returned transition clip(s) then settles on the target scale's clip.
 const $ = (id) => document.getElementById(id);
 const vid = $("vid"), tint = $("tint"), overlay = $("overlay"), black = $("black"), readout = $("readout");
 
-let clip = null;           // active clip manifest entry
-let currentVariant = -1;   // last loaded Right strength
+let clipsById = {};        // id -> clip manifest entry
+let ring = null;           // {scales:[{id,clip_id,title}], transitions:[...]} or null
+let ringIndex = 0;         // current scale position on the ring
+let currentVariant = -1;   // last loaded Right strength (reset on clip change)
+let busy = false;          // true while a ring transition is playing
 
-async function loadClips() {
-  const data = await (await fetch("/api/clips")).json();
-  clip = data.clips[0] || null;
+async function loadData() {
+  const clips = (await (await fetch("/api/clips")).json()).clips || [];
+  clipsById = Object.fromEntries(clips.map((c) => [c.id, c]));
+  const r = await fetch("/api/ring");
+  ring = r.ok ? await r.json() : null;
+  if (!ring && clips.length) {
+    // No ring: single-clip mode — synthesize a 1-scale ring over clip 0.
+    ring = { scales: [{ id: clips[0].id, clip_id: clips[0].id, title: clips[0].title }], transitions: [] };
+  }
+  ringIndex = 0;
+}
+
+function activeClip() {
+  if (!ring) return null;
+  return clipsById[ring.scales[ringIndex].clip_id] || null;
 }
 
 function mediaUrl(file) { return "/media/" + file; }
 
 function variantFile(strength) {
+  const clip = activeClip();
+  if (!clip) return "";
   const v = clip.right_variants[String(strength)];
   return v ? v.file : clip.base_file;
 }
@@ -37,12 +57,14 @@ function loadVariant(strength) {
   vid.style.opacity = "0";
   setTimeout(() => {
     vid.src = mediaUrl(variantFile(strength));
+    vid.loop = true;
     vid.play().catch(() => {});
     vid.style.opacity = "1";
   }, 150);
 }
 
 function renderOverlay(level, intensity) {
+  const clip = activeClip();
   overlay.innerHTML = "";
   if (!clip || level <= 0) { overlay.style.opacity = "0"; return; }
   overlay.style.opacity = String(intensity);
@@ -63,6 +85,12 @@ function renderOverlay(level, intensity) {
   }
 }
 
+function renderScaleReadout() {
+  if (!ring) return;
+  const s = ring.scales[ringIndex];
+  $("scale-name").textContent = `${s.title}  (${ringIndex + 1}/${ring.scales.length})`;
+}
+
 function controls() {
   return {
     content: $("content").value,
@@ -79,6 +107,7 @@ function calibration() {
 
 let timer = null;
 async function update() {
+  if (busy) return;
   const resp = await fetch("/api/alteration", {
     method: "POST", headers: { "content-type": "application/json" },
     body: JSON.stringify({ controls: controls(), calibration: calibration() }),
@@ -95,11 +124,69 @@ async function update() {
 
 function debounced() { clearTimeout(timer); timer = setTimeout(update, 80); }
 
+// --- Scale ring (endless encoder) ---
+
+function playTransition(file) {
+  // Play one placeholder zoom/warp transition clip start-to-finish, with the
+  // alteration layers hidden. Resolves on 'ended' (or a safety timeout).
+  return new Promise((resolve) => {
+    overlay.style.opacity = "0";
+    tint.style.opacity = "0";
+    vid.style.filter = "none";
+    vid.loop = false;
+    vid.style.opacity = "1";
+    vid.src = mediaUrl(file);
+    let done = false;
+    const finish = () => { if (done) return; done = true; vid.removeEventListener("ended", finish); resolve(); };
+    vid.addEventListener("ended", finish);
+    vid.play().catch(finish);
+    setTimeout(finish, 6000);
+  });
+}
+
+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 }),
+    });
+    if (!resp.ok) return;
+    const move = await resp.json();
+    for (const step of move.steps) {
+      await playTransition(step.file);
+    }
+    ringIndex = move.to_index;
+    currentVariant = -1;        // force the target clip's variant to (re)load
+    renderScaleReadout();
+  } finally {
+    busy = false;
+    update();
+  }
+}
+
+let wheelAccum = 0, wheelTimer = null;
+function onWheel(e) {
+  e.preventDefault();
+  wheelAccum += e.deltaY;
+  clearTimeout(wheelTimer);
+  wheelTimer = setTimeout(() => {
+    const detents = Math.trunc(wheelAccum / 60) || (wheelAccum > 0 ? 1 : -1);
+    wheelAccum = 0;
+    if (detents) advance(detents);   // wheel down = zoom inward (+)
+  }, 90);
+}
+
 async function main() {
-  await loadClips();
+  await loadData();
+  renderScaleReadout();
   for (const id of ["content", "left", "right", "dark", "light", "mood_gain", "overlay_gain"]) {
     $(id).addEventListener("input", debounced);
   }
+  $("zoom-in").addEventListener("click", () => advance(1));
+  $("zoom-out").addEventListener("click", () => advance(-1));
+  $("stage").addEventListener("wheel", onWheel, { passive: false });
   update();
 }
 main();

simulator/static/index.html

@@ -9,7 +9,7 @@
 <body>
   <header><h1>Human Experience Filter — Alteration Preview</h1></header>
   <main>
-    <section class="stage">
+    <section class="stage" id="stage">
       <div class="screen">
         <video id="vid" loop muted playsinline></video>
         <div id="tint"></div>
@@ -32,6 +32,16 @@
         </select>
       </fieldset>
 
+      <fieldset>
+        <legend>Scale ring (endless encoder)</legend>
+        <div class="ring-control">
+          <button type="button" id="zoom-out" title="zoom out (toward cosmos)">⊖ out</button>
+          <span id="scale-name" class="scale-name">—</span>
+          <button type="button" id="zoom-in" title="zoom in (toward microscopic)">in ⊕</button>
+        </div>
+        <p class="hint">Relative, endless — wraps past the smallest back to the largest. Scroll the stage too.</p>
+      </fieldset>
+
       <fieldset>
         <legend>Experience knobs (0–4)</legend>
         <label>Left (analytical) <input type="range" id="left" min="0" max="4" value="0" /></label>

simulator/static/style.css

@@ -23,3 +23,10 @@ label { display: block; margin: 0.4rem 0; }
 input[type=range], select { width: 100%; }
 #readout { background: #000; padding: 0.5rem; border-radius: 4px; font-size: 12px;
            white-space: pre-wrap; max-height: 240px; overflow: auto; }
+.ring-control { display: flex; align-items: center; gap: 0.4rem; }
+.ring-control button { flex: 0 0 auto; background: #1a2436; color: #9af;
+           border: 1px solid #345; border-radius: 4px; padding: 0.3rem 0.5rem;
+           cursor: pointer; font-size: 13px; }
+.ring-control button:hover { background: #243352; }
+.scale-name { flex: 1 1 auto; text-align: center; font-size: 12px; color: #cde; }
+.hint { margin: 0.3rem 0 0; font-size: 11px; color: #789; }

tests/test_clips.py

@@ -2,7 +2,14 @@ import json
 
 import pytest
 
-from simulator.clips import Clip, load_manifest
+from player.ring import RingMove, ScaleRing, TransitionStep, advance_ring
+from simulator.clips import (
+    Clip,
+    load_manifest,
+    load_ring,
+    ring_move_to_dict,
+    ring_to_dict,
+)
 
 
 def _manifest_dict():
@@ -67,3 +74,72 @@ def test_clip_serializes_to_dict_for_the_api(tmp_path):
 def test_missing_manifest_raises(tmp_path):
     with pytest.raises(FileNotFoundError):
         load_manifest(tmp_path / "nope.json")
+
+
+def _ring_manifest_dict():
+    return {
+        "clips": [],
+        "ring": {
+            "scales": [
+                {"id": "cosmos", "clip_id": "cosmos"},
+                {"id": "forest", "clip_id": "forest"},
+                {"id": "abyss", "clip_id": "abyss"},
+            ],
+            "transitions": [
+                {"file": "transitions/cosmos-forest.mp4", "model": "placeholder"},
+                {"file": "transitions/forest-abyss.mp4", "model": "placeholder"},
+                {"file": "transitions/abyss-cosmos.mp4", "model": "placeholder"},
+            ],
+        },
+    }
+
+
+def test_load_ring_builds_a_scale_ring(tmp_path):
+    p = tmp_path / "manifest.json"
+    p.write_text(json.dumps(_ring_manifest_dict()))
+    ring = load_ring(p)
+    assert isinstance(ring, ScaleRing)
+    assert len(ring) == 3
+    assert ring.scales[0].id == "cosmos"
+    assert ring.scales[0].clip_id == "cosmos"
+    assert ring.transitions[2].file == "transitions/abyss-cosmos.mp4"
+    assert ring.transitions[0].model == "placeholder"
+
+
+def test_load_ring_is_none_when_absent(tmp_path):
+    p = tmp_path / "manifest.json"
+    p.write_text(json.dumps(_manifest_dict()))  # no "ring" key
+    assert load_ring(p) is None
+
+
+def test_ring_to_dict_carries_scale_titles_from_clips(tmp_path):
+    p = tmp_path / "manifest.json"
+    md = _ring_manifest_dict()
+    md["clips"] = [
+        {"id": "cosmos", "title": "NASA cosmos", "base_file": "cosmos/base.mp4"},
+        {"id": "forest", "title": "Yosemite", "base_file": "forest/base.mp4"},
+        {"id": "abyss", "title": "NOAA abyss", "base_file": "abyss/base.mp4"},
+    ]
+    p.write_text(json.dumps(md))
+    ring = load_ring(p)
+    clips = load_manifest(p)
+    d = ring_to_dict(ring, clips)
+    assert [s["id"] for s in d["scales"]] == ["cosmos", "forest", "abyss"]
+    assert d["scales"][0]["title"] == "NASA cosmos"
+    assert d["scales"][0]["clip_id"] == "cosmos"
+    assert d["transitions"][2]["file"] == "transitions/abyss-cosmos.mp4"
+
+
+def test_ring_move_to_dict_serializes_steps(tmp_path):
+    p = tmp_path / "manifest.json"
+    p.write_text(json.dumps(_ring_manifest_dict()))
+    ring = load_ring(p)
+    move = advance_ring(ring, from_index=2, delta=1)  # abyss -> wrap -> cosmos
+    d = ring_move_to_dict(move, ring)
+    assert d["from_index"] == 2
+    assert d["to_index"] == 0
+    assert d["wrapped"] is True
+    assert d["target_clip_id"] == "cosmos"
+    assert d["steps"][0]["file"] == "transitions/abyss-cosmos.mp4"
+    assert d["steps"][0]["reversed"] is False
+    assert d["steps"][0]["to_index"] == 0

tests/test_player_ring.py

@@ -0,0 +1,138 @@
+import pytest
+
+from player.ring import (
+    RingError,
+    RingMove,
+    Scale,
+    ScaleRing,
+    Transition,
+    TransitionStep,
+    advance_ring,
+    scale_at,
+)
+
+
+def _ring():
+    # cosmos (largest, idx 0) -> forest -> abyss (smallest) -> wraps to cosmos
+    return ScaleRing(
+        scales=(
+            Scale(id="cosmos", clip_id="cosmos"),
+            Scale(id="forest", clip_id="forest"),
+            Scale(id="abyss", clip_id="abyss"),
+        ),
+        transitions=(
+            Transition(file="t/cosmos-forest.mp4"),   # edge 0: cosmos->forest
+            Transition(file="t/forest-abyss.mp4"),     # edge 1: forest->abyss
+            Transition(file="t/abyss-cosmos.mp4"),      # edge 2: abyss->cosmos (wrap)
+        ),
+    )
+
+
+def test_ring_needs_one_transition_per_scale():
+    with pytest.raises(RingError):
+        ScaleRing(
+            scales=(Scale("a", "a"), Scale("b", "b")),
+            transitions=(Transition("t/ab.mp4"),),  # 1 edge for 2 scales
+        )
+
+
+def test_ring_rejects_empty():
+    with pytest.raises(RingError):
+        ScaleRing(scales=(), transitions=())
+
+
+def test_scale_at_wraps_modulo():
+    r = _ring()
+    assert scale_at(r, 0).id == "cosmos"
+    assert scale_at(r, 3).id == "cosmos"   # wraps
+    assert scale_at(r, -1).id == "abyss"    # negative wraps
+    assert scale_at(r, 4).id == "forest"
+
+
+def test_advance_one_step_inward_plays_edge_forward():
+    r = _ring()
+    move = advance_ring(r, from_index=0, delta=1)
+    assert isinstance(move, RingMove)
+    assert move.from_index == 0
+    assert move.to_index == 1
+    assert move.wrapped is False
+    assert move.steps == (
+        TransitionStep(edge=0, reversed=False, file="t/cosmos-forest.mp4", to_index=1),
+    )
+
+
+def test_advance_one_step_outward_plays_edge_reversed():
+    r = _ring()
+    move = advance_ring(r, from_index=1, delta=-1)
+    assert move.to_index == 0
+    assert move.wrapped is False
+    # going forest(1) -> cosmos(0) is edge 0 played in reverse
+    assert move.steps == (
+        TransitionStep(edge=0, reversed=True, file="t/cosmos-forest.mp4", to_index=0),
+    )
+
+
+def test_advance_inward_past_smallest_wraps_to_largest():
+    r = _ring()
+    # at abyss (smallest, idx 2), zoom in -> wraps to cosmos (idx 0) via edge 2
+    move = advance_ring(r, from_index=2, delta=1)
+    assert move.to_index == 0
+    assert move.wrapped is True
+    assert move.steps == (
+        TransitionStep(edge=2, reversed=False, file="t/abyss-cosmos.mp4", to_index=0),
+    )
+
+
+def test_advance_outward_past_largest_wraps_to_smallest():
+    r = _ring()
+    # at cosmos (idx 0), zoom out -> wraps to abyss (idx 2) via edge 2 reversed
+    move = advance_ring(r, from_index=0, delta=-1)
+    assert move.to_index == 2
+    assert move.wrapped is True
+    assert move.steps == (
+        TransitionStep(edge=2, reversed=True, file="t/abyss-cosmos.mp4", to_index=2),
+    )
+
+
+def test_advance_multi_detent_chains_transitions():
+    r = _ring()
+    move = advance_ring(r, from_index=0, delta=2)
+    assert move.to_index == 2
+    assert move.wrapped is False
+    assert move.steps == (
+        TransitionStep(edge=0, reversed=False, file="t/cosmos-forest.mp4", to_index=1),
+        TransitionStep(edge=1, reversed=False, file="t/forest-abyss.mp4", to_index=2),
+    )
+
+
+def test_advance_full_loop_returns_to_start_and_marks_wrap():
+    r = _ring()
+    move = advance_ring(r, from_index=0, delta=3)
+    assert move.to_index == 0
+    assert move.wrapped is True
+    assert len(move.steps) == 3
+
+
+def test_advance_zero_is_a_noop():
+    r = _ring()
+    move = advance_ring(r, from_index=1, delta=0)
+    assert move.from_index == 1
+    assert move.to_index == 1
+    assert move.steps == ()
+    assert move.wrapped is False
+
+
+def test_advance_normalizes_from_index():
+    r = _ring()
+    # from_index out of range is taken modulo N first
+    move = advance_ring(r, from_index=3, delta=1)
+    assert move.from_index == 0
+    assert move.to_index == 1
+
+
+def test_degenerate_single_scale_ring_is_a_noop():
+    r = ScaleRing(scales=(Scale("solo", "solo"),), transitions=())
+    move = advance_ring(r, from_index=0, delta=5)
+    assert move.to_index == 0
+    assert move.steps == ()
+    assert move.wrapped is False

tests/test_simulator_api.py

@@ -88,3 +88,85 @@ def test_index_is_served():
     assert resp.status_code == 200
     assert "text/html" in resp.headers["content-type"]
     assert "Alteration" in resp.text
+
+
+@pytest.fixture
+def ring_manifest_path(tmp_path):
+    p = tmp_path / "manifest.json"
+    p.write_text(json.dumps({
+        "clips": [
+            {"id": "cosmos", "title": "NASA cosmos", "base_file": "cosmos/base.mp4",
+             "license": "PD", "source": "NASA", "right_variants": {},
+             "annotations": [], "strings": {}},
+            {"id": "forest", "title": "Yosemite", "base_file": "forest/base.mp4",
+             "license": "poc", "source": "hef-poc",
+             "right_variants": {"4": {"file": "forest/right4.mp4"}},
+             "annotations": [], "strings": {}},
+            {"id": "abyss", "title": "NOAA abyss", "base_file": "abyss/base.mp4",
+             "license": "PD", "source": "NOAA", "right_variants": {},
+             "annotations": [], "strings": {}},
+        ],
+        "ring": {
+            "scales": [
+                {"id": "cosmos", "clip_id": "cosmos"},
+                {"id": "forest", "clip_id": "forest"},
+                {"id": "abyss", "clip_id": "abyss"},
+            ],
+            "transitions": [
+                {"file": "transitions/cosmos-forest.mp4", "model": "placeholder"},
+                {"file": "transitions/forest-abyss.mp4", "model": "placeholder"},
+                {"file": "transitions/abyss-cosmos.mp4", "model": "placeholder"},
+            ],
+        },
+    }))
+    return p
+
+
+@pytest.fixture
+def ring_client(ring_manifest_path):
+    return TestClient(create_app(manifest_path=ring_manifest_path))
+
+
+def test_ring_returns_scales_and_transitions(ring_client):
+    resp = ring_client.get("/api/ring")
+    assert resp.status_code == 200
+    data = resp.json()
+    assert [s["id"] for s in data["scales"]] == ["cosmos", "forest", "abyss"]
+    assert data["scales"][0]["title"] == "NASA cosmos"
+    assert len(data["transitions"]) == 3
+
+
+def test_ring_advance_inward_one_step(ring_client):
+    resp = ring_client.post("/api/ring/advance", json={"from_index": 0, "delta": 1})
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["to_index"] == 1
+    assert data["target_clip_id"] == "forest"
+    assert data["wrapped"] is False
+    assert data["steps"][0]["file"] == "transitions/cosmos-forest.mp4"
+    assert data["steps"][0]["reversed"] is False
+
+
+def test_ring_advance_wraps_smallest_to_largest(ring_client):
+    resp = ring_client.post("/api/ring/advance", json={"from_index": 2, "delta": 1})
+    data = resp.json()
+    assert data["to_index"] == 0
+    assert data["target_clip_id"] == "cosmos"
+    assert data["wrapped"] is True
+
+
+def test_ring_advance_outward_reverses_edge(ring_client):
+    resp = ring_client.post("/api/ring/advance", json={"from_index": 1, "delta": -1})
+    data = resp.json()
+    assert data["to_index"] == 0
+    assert data["steps"][0]["reversed"] is True
+
+
+def test_ring_404_when_no_ring_in_manifest(client):
+    assert client.get("/api/ring").status_code == 404
+    assert client.post("/api/ring/advance", json={"from_index": 0, "delta": 1}).status_code == 404
+
+
+def test_ring_advance_rejects_bad_delta(ring_client):
+    resp = ring_client.post("/api/ring/advance", json={"from_index": 0, "delta": "x"})
+    assert resp.status_code == 422