# Session 0037.0 — Transcript

> App: human-experience-filter-art
> Start: 2026-06-30T10-42 (PST)
> Type: planning-and-executing
> Posture: yolo
> Claude-Session: aa7ac424-d797-4918-8837-2a904441d91e
> Checkout: /Users/benstull/git/benstull.org/benstull/human-experience-filter-art/.claude/worktrees/session-0037-altitude-snap-on-release
> End: 2026-06-30T10-52 (PST)
> Status: **FINALIZED.**

## Summary

Single-task UX session. Made the altitude dial **snap to the closest altitude on
drag release** so a grab-and-release always lands on a discrete altitude, just
like a tap/label-click.

### Arc

1. Claimed session 0037 (two stale `--INPROGRESS` placeholders 0015/0017 noted,
   not live). Worked in an isolated worktree
   (`session-0037-altitude-snap-on-release`) branched off `origin/main` (local
   `main` was 7 behind).
2. Located the behavior: `onDialUp` (`simulator/static/app.js`) held the live
   blend wherever a real turn stopped — the "no auto-complete" continuous-encoder
   model. Tap path (`moved < 6` → `jumpToScale`) and wheel/label auto-scrub were
   already snap-to-altitude.
3. TDD: added an `altitude-lock.spec.ts` e2e ("releasing a partial drag snaps to
   the closest altitude") — confirmed RED (held pos never became integer).
4. Implemented: a real turn (`moved >= 6`) now `autoScrub(Math.round(pos))` →
   short scrub to the nearest altitude, settle + lock (frac 0). Reduced motion is
   handled inside `autoScrub` (jump-to-target). GREEN.
5. Verified: full altitude-lock (14) + a11y + i18n e2e suites green. Committed,
   pushed, opened PR #31, merged to `main` (`5696b94`).

### Pipeline (§9)

This app is **exempt** from flotilla/PPE/§9 prod gate — public target is static
Cloudflare (Pages + R2). Change is merged to `main`; **operator redeploy** of the
static build is the remaining ship step. No plan artifact archived: the change
was a trivial leaf `task`, planned inline (no separate plan file; app has no
content repo).

### Next session

Operator by-eye review of the snap feel on the live sim, then redeploy to
Cloudflare.

## Launch prompt

> When the user is dragging the slider (rather than clicking on an altitude),
> let's transition to the closest altitude when they let go. That way, the user
> will always land on an altitude as if they clicked one, even if they're
> grabbing and releasing the slider.

## Plan

> Anchor: leaf `task` (UX behavior tweak — directly plan-eligible, R2b).

Snap-on-release for the altitude dial. Today `onDialUp` (app.js) holds the live
blend wherever a drag stops (the "no auto-complete" continuous-encoder model).
Change: after a real turn (`moved >= 6`), `autoScrub(Math.round(pos))` so the
knob settles on the CLOSEST altitude (frac 0 → lock), identical to a tap/click.
Tap path (`moved < 6` → `jumpToScale`) unchanged. Reduced-motion is handled by
`autoScrub` (jump-to-target, no tween).

Verification: new e2e in `altitude-lock.spec.ts` ("releasing a partial drag
snaps to the closest altitude") — TDD red→green; full altitude-lock (14) + a11y
+ i18n suites green. Project is exempt from §9/PPE (static Cloudflare target);
ships branch → PR → merge → operator redeploy.

## 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._
