# Session 0028.0 — Transcript

> App: human-experience-filter-art
> Start: 2026-06-30T06-53 (PST)
> Type: planning-and-executing
> Posture: yolo
> Claude-Session: d9da7994-e036-4b7c-b2d4-d2675ac4e5a1
> Checkout: /Users/benstull/git/benstull.org/benstull/human-experience-filter-art
> Status: **FINALIZED.**
> Worktree: `worktree-session-0028` (isolated; concurrent session in flight). Torn down at finalize.
> Outcome: D3 reverse-landing frame jump FIXED, app-side. PR #30 → main (`582183d`).

## Launch prompt

`/goal next` — operator then directed: "There's a concurrent session — do this one out
of a worktree in a different dir." Session 0028 runs isolated in worktree
`worktree-session-0028` while a concurrent session owns the simulator startup ("Run
simulation" button: `index.html`/`style.css`/`i18n.js`).

## Plan

> Anchor: leaf bug — D3 reverse-landing frame jump (no tracker issue; the s0027 capture
> token returned 401. Residual flagged in the altitude-morph-and-scrub memory note +
> scrub-driven-transitions design.)

**Goal:** kill the ~3-second frame jump when ASCENDING the altitude dial and landing on
the higher-altitude clip.

**Root cause (verified by reading the bake + player):** each baked morph
`transitions/{h}__{l}.mp4` spans `src(h)@0s` (frac 0) → `dst(l)@~LOOP_TAIL_S` (frac 1),
and the scrub uses this single forward file in BOTH directions. The steady loop element
always seeks to `LOOP_TAIL_S` (3.0s) on landing. So:
- DESCEND (dir>0) lands on `dst` at frac 1 → morph ends `dst@3` ≈ loop@3 → seamless ✓
  (the s0026 "loop-from-tail" fix).
- ASCEND (dir<0) lands on `src` at frac 0 → morph shows `src@0`, but loop seeks `src@3`
  → ~3s jump ✗ (D3).

**Fix (app-side, no media re-bake — beats re-baking 154 LFS morphs):** make the loop
landing frame DIRECTION-AWARE. On a reverse landing seek the loop to 0 (= the morph's
frac-0 frame) and wrap `[0,dur]` (the base is already a seamless crossfade-loop); forward
keeps `[LOOP_TAIL_S,dur]`. Pure decision extracted to `scrub.js loopLandFrame(dir,
loopTailS)` + node tests; wired through `loadLoop`/settle/wrap handlers in `app.js`.

**Tasks:**
1. TDD `HEFScrub.loopLandFrame(dir, loopTailS)` in `scrub.js` (+ `scrub.test.js`).
2. Wire `app.js`: `loadLoop(clip, landFrame)`, directional settle seek, `dataset.loopStart`
   in the `timeupdate`/`ended` wrap handlers.
3. Add a reverse-landing e2e (mirror of the existing forward "loops from tail" test).
4. Verify: node unit tests + pytest + e2e (best-effort) all green.
5. Branch → PR → merge (yolo). PPE/E2E machinery not built for this app (§10.6) — local
   green is the bar; prod promotion stays operator-gated.

## Deferred decisions

_Autonomous-mode low-confidence calls the driver made and would have
liked operator input on. Appended as the session runs; surfaced at
finalize. Empty if none._

- **Fix shape: app-side direction-aware loop landing, NOT a 154-morph re-bake.** The
  s0026 memory note guessed the D3 fix would be "per-clip loop files." Reading the bake +
  player showed the root cause is simpler: the morph's frac-0 frame is `src@0` but the
  loop always seeked the tail (`LOOP_TAIL_S`). Fixed entirely in `app.js`/`scrub.js` by
  landing the loop on the morph's actual frac-0 frame (0) when ascending. This avoids
  re-baking 154 LFS morphs (no media churn, a tiny reviewable diff, the base clips are
  already seamless crossfade-loops so `[0,dur]` wraps cleanly). Alternative considered:
  re-bake morphs to start at `src@LOOP_TAIL_S` — heavier, no benefit.
- **Pre-existing e2e failure left as-is:** `loop-recovery.spec.ts` fails in this
  environment on the CLEAN baseline too (verified by stashing my changes). It boots
  without enabling video, so the loop's `loopTail` is never armed and the `ended` guard
  returns early. Not introduced here; my change preserves that guard exactly. Worth a
  separate look (the test likely needs to `enableVideo` first), but out of scope for D3.
- **Could not verify by eye.** The fix is logic- and test-verified (node + the new
  reverse-landing e2e asserting the loop anchors at the head, not the tail); the actual
  visual seamlessness of an ascending landing still wants an operator eyeball in the
  running sim.

## Session arc

1. Claimed session **0028** (race-free, via git). Two stale `--INPROGRESS` placeholders
   (0015, 0017) noted as orphaned, left untouched.
2. Baseline survey surfaced uncommitted `run-sim` button edits + main behind by 2
   (session commits). Operator confirmed a **concurrent session** owns that startup work
   and directed isolation → created worktree `worktree-session-0028` off `origin/main`,
   leaving the concurrent session's edits in the canonical clone untouched.
3. Orientation: in-repo `docs/ROADMAP.md` is stale (formal frontier = deferred hardware);
   live frontier is in memory. Stored `/goal next` (0027's by-eye annotation review) is
   operator-eyes work I can't complete; the run-sim button is the concurrent session's.
   Asked the operator to pick 0028's disjoint item → **D3 reverse-landing fix**.
4. Read the bake (`build_pool_manifest.transition_cmd`) + player (`app.js` loop/morph) to
   pin the root cause (morph spans `src@0`→`dst@tail`; loop always seeks the tail).
5. TDD: `HEFScrub.loopLandFrame` (red → green), then wired `app.js`
   (`loadLoop(clip,landFrame)`, `dataset.loopStart`, directional settle, wrap handlers).
6. Added a reverse-landing e2e. Verified: node 16/16, **altitude-lock e2e 12/12** (forward
   no-regression + new reverse test), pytest 299 pass. Confirmed `loop-recovery.spec.ts`
   fails on the clean baseline too (pre-existing, not mine) by stashing.
7. Committed → PR #30 → merged to `main` (`582183d`) → deleted branch. Updated memory.

## Cut state

- **On `main` (`582183d`):** D3 fix — `simulator/static/scrub.js` (+`loopLandFrame`),
  `simulator/static/app.js` (direction-aware loop landing), `simulator/unit/scrub.test.js`,
  `simulator/e2e/tests/altitude-lock.spec.ts` (reverse-landing test).
- **Tests:** node 16/16; altitude-lock e2e 12/12; pytest 299 pass / 3 pre-existing
  env-only failures (real-ffprobe/ffmpeg + ML detect; untouched — no Python changed) / 4
  skipped. `loop-recovery.spec.ts` is a pre-existing baseline failure in this env.
- **§9 / deploy:** this whole project is **exempt** from flotilla/PPE/§9 (memory:
  project-exempt-from-wiggleverse-deploy; public target is static Cloudflare). Local-green
  is the bar — met. No PPE stage to run.
- **No plan artifact archived:** fused leaf fix, plan inline in this transcript; app has
  **no content repo** (`CONTENT_REMOTE` empty) — nothing to archive.

## Operator plate

- **Review by eye** an ASCENDING altitude landing in the running sim — confirm the
  ~3s reverse-landing jump is gone (logic/test-verified only; no Chrome on box here).
- Still standing from s0027: by-eye review of the 28 left-brain annotations (4 langs);
  decide on tracked labels for abyss/reef creature clips.
- A concurrent session was shipping the "Run simulation" startup button — reconcile/land
  that separately (its edits are in the canonical clone, not touched here).

## Next-session prompt

```
/goal Review by eye in the running simulator: (1) an ASCENDING altitude landing — confirm the D3 reverse-landing frame jump is gone; (2) the 28 left-brain annotations across en/es/fr/ja, correcting any species/box that reads wrong; then decide whether the abyss/reef creature clips should get tracked labels via author mode.
```
