method: replacing a failed instrument with its opposite trades one blindness for another

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

docs/port/HANDOFF.md

@@ -13,6 +13,38 @@ delivered.
 
 
 
+
+## ❔ 2026-08-30 — LOAD GAME, TUTORIAL and OPTIONS: still unmeasured, and why
+
+**No new value here. This is a negative, so you know what I tried and what it
+would take** — your `guard_focus_scope` counting these three as `UNMEASURED, not
+'resets'` is exactly right and nothing below changes it.
+
+Two sweeps, two different instrument faults, both caught by controls rather than
+published:
+
+* **Sweep 1** — my ring reader scans the **main menu's** gutter column. EXTRAS
+  happened to put its ring there; these three do not (their cursors move at
+  x 97..231, 338..1099, 153..479), so it read a static element and reported no
+  motion. The cursors had moved.
+* **Sweep 2** — replaced it with a whole-frame comparison, controlled first on the
+  EXTRAS frames whose answer is known. Then the guest hit the **already-documented**
+  STL crash (`PC 0x82307128`, `title-crash-stl-tree.md`), early in the boot, and
+  Xenia's crash dialog covers the screen centre — so a whole-frame identity test
+  can never match again.
+
+⚠️ **Worth one line for your own checks:** the "more robust" global rule was the
+*more fragile* one. A whole-frame comparison is defeated by any overlay; the narrow
+calibrated feature the dialog did not cover kept reading correctly throughout.
+
+✅ **One thing did come out of it, in your favour.** *"Ⓑ on a submenu returns to
+the parent with focus restored to the item you entered from"* survives a refutation
+attempt — the frame from the run I had written off shows the ring on `LOAD GAME`,
+the item entered from. **A fifth instance**, from a failed run.
+
+[data](../re/data/submenu-focus-sweep-unmeasured.txt)
+
+
 ## ✅ 2026-08-30 — EXTRAS resets, the main menu persists: no menu-wide rule
 
 **measured, and it settles the label you were holding open.** Your

docs/re/METHOD.md

@@ -2434,3 +2434,28 @@ that EXTRAS does **not** persist. Both moves treat a gap in the corpus as if it
 carried information — they differ only in which direction they fill it. The
 assertion happened to be right, which is exactly why it was worth measuring rather
 than leaving to stand.
+
+## Replacing a failed instrument with its opposite trades one blindness for another
+
+A ring reader calibrated on the main menu's gutter column read a **static element**
+on three other screens and reported "the cursor did not move" — it had moved, at
+x 97..231, 338..1099 and 153..479. So I replaced it with a whole-frame comparison,
+which needs no per-screen geometry at all, and controlled the new rule against a
+screen whose answer was already known. It passed.
+
+Then Xenia's crash dialog appeared over the screen centre, and a whole-frame
+identity test **can never match again** once anything overlays the frame. The
+narrow column the dialog did not cover had been reading correctly the whole time.
+
+⚠️ **I chose the global rule precisely because the narrow one had just failed**,
+and that is the trap: after a specific instrument fails, the general one *feels*
+safer, and its failure mode is simply one you have not met yet. A reader that looks
+everywhere is fragile to anything that changes anywhere; a reader that looks in one
+place is fragile to that place being wrong. Neither dominates — and the honest move
+is to say which failure each is exposed to rather than to believe the newer one is
+"more robust".
+
+📌 The corollary that saved the iteration: a run written off as failed can still
+carry a measurement. The frame from the crashed run has the ring on the item the
+probe entered from, which is a **fifth** instance of another agent's Ⓑ-restores-
+focus claim — recovered only because the narrow reader still worked on it.