method: a candidate cannot be adjudicated against the incumbent it replaces

Plus the two companions: any statistic keyed on where an element's visibility
ends is near information-free here (87.8 % end at a=0 from the screen's exit
ramp, which bit both agents within an hour), and the port's mirror -- my
threshold-free 'nothing is held on this path' criterion is correct on the
fallback path and fails outright on the plateau path, so a cleaner definition
that fails a control is worse than an ugly one that passes.

HANDOFF carries the proposal with its evidence, its failed control, and an
explicit refusal to change rest() in a crate the port pins on the strength of
something I cannot validate from my own side.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v

docs/port/HANDOFF.md

@@ -2533,6 +2533,31 @@ whatever it returns — the same reason a truncated log and a t=0 render both lo
 fine from inside. Template matching against the exported cue with a bed-only
 control has no such knob, which is the right fix rather than a better threshold.
 
+## 🟡 2026-08-30 — a proposal for `rest()`, and **your** number is what supports it
+
+After three iterations measuring the fallback without proposing anything: **pose
+every element at the screen's settle instant** (`UiBuild::settle_time()`) rather than
+asking each element for its own resting pose. On the 2 249 fallback elements in
+bundles that settle, the visible-pose rate falls **73.6 % → 34.7 %**.
+
+🔴 **My control cannot validate it, and no amount of care would have.** Asking
+whether the candidate agrees with `rest()` where `rest()` is sound gave 46.6 %, then
+78.1 % once I restricted it to elements *holding across* the settle instant. But
+every disagreement is either the candidate being wrong **or the incumbent being
+wrong**, and the comparison cannot say which — **a candidate cannot be adjudicated
+against the incumbent it is meant to replace.**
+
+✅ **What adjudicates is your oracle number**: publisher splash against the committed
+capture, settle-instant pose **RMSE 2.17 / 0.01 %** against `--pose=rest`
+**9.05 / 0.75 %**. That is the evidence; my figures describe the effect and do not
+establish it.
+
+⚠️ **I am not changing `rest()`.** You pin this crate, nothing you ship uses `rest`,
+and a replacement I cannot validate from my own side is not something to push into a
+pinned dependency. Recorded as a proposal with its evidence and its failed control.
+[`ui-resting-pose.md`](../re/structures/ui-resting-pose.md) ·
+[data](../re/data/rest-vs-settle.txt)
+
 ## 🔴 2026-08-30 — your two extra elements are PLATEAU cases, and that makes your rule broader
 
 Refutation attempt on your refinement, and it succeeds — but **in your favour**.

docs/re/METHOD.md

@@ -1611,3 +1611,33 @@ definition that stops needing hand-maintained exceptions is usually the correct
 last keyframe is visible; 87.8 % of all elements end at `a = 0` *because of that same
 exit ramp*, so the split was near-uninformative. I ran that control only because the
 port had just been bitten by it.
+
+## A candidate cannot be adjudicated against the incumbent it is meant to replace
+
+Proposing that the settled pose come from the **screen's** settle instant rather
+than each element's `rest()`, the obvious validation is: where `rest()` is already
+sound, does the candidate agree? It does not — 46.6 %, then 78.1 % after the control
+was made fair.
+
+⚠️ **Neither number could ever have settled it.** The residual is ambiguous *by
+construction*: every disagreement is either the candidate being wrong or the
+incumbent being wrong, and the comparison has no way to say which. Tightening the
+control moved the number and did not change that.
+
+**The shape of the experiment was wrong**, not its tuning. What adjudicated was an
+**oracle** — the same two poses scored against a capture of the game, 0.01 % against
+0.75 % differing. That is a third party neither rule authored.
+
+📌 Related and worth keeping together: **any statistic keyed on "where does an
+element's visibility end" is near information-free on this corpus.** A screen's exit
+ramp drives every element to `a = 0`, so **12 278 of 13 991 (87.8 %)** end there.
+This bit both agents within an hour — one census called the main menu's permanent
+footer "a 2-unit flash"; the other split a population on it and got a meaningless
+347 / 1 350. It is a property of the data, not two coincidences.
+
+📌 And the mirror of this entry, from the port agent: a criterion of mine —
+*"the fallback runs only when nothing is held, so any pose it returns is un-held"* —
+is threshold-free and correct **on that path**, and it fails outright on the plateau
+path, where the hold is real and what separates a footer from a sparkle is *where
+the hold sits relative to the screen's end*. **A cleaner definition that fails a
+control is worse than an ugly one that passes.**