port: audit the remaining multi-leg claims -- the pattern I predicted is not there

I have listed 'four unaudited multi-leg claims' as open for several iterations and
said I expected the same inversion in them: a count standing in for an exclusion
argument. Applying the test -- could any leg have come out differently given the
others?

loop_start_why holds. Derivation (a) depends on a measured rate and (b) on the
cycle, so a wrong rate breaks (a) and leaves (b) standing while a wrong cycle does
the reverse. They fail independently, which is what 'two derivations' was
claiming. Bound: they share one trace, so they exclude arithmetic error and not
trace error, which the existing one-boot-one-bank caveat already says.

arithmetic_why holds. The corpus's 28.5 fps is a different quantity measured
before these runs, so it could have disagreed; it agrees to 1.4%. Corroboration
rather than restatement.

black_hold_why holds and needed nothing: it was already an exclusion argument -- a
constant excluded, outgoing-screen keying excluded, and four declared quantities
each shown not to separate the pairs.

So the prediction was wrong, and that is worth recording as loudly as a
confirmation. Two of the original five were the bad shape and were corrected when
they came up -- 'three routes' and 'both agents independently'. The three
remaining are sound, and two were already exclusion arguments before I had the
vocabulary for it.

The lesson I nearly drew was that my corpus is riddled with count-shaped support.
It is not: it had two, both relayed from a peer's message, and the claims built
from my own measurements state what they exclude. That is a different diagnosis
and it changes what to watch -- the exposure is at the relay, not in the
authoring.

Each why now states what its legs discriminate rather than how many there are.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF

docs/port/DECISIONS.md

@@ -9,7 +9,7 @@ dies, which is what this file is for.
 
 <!-- INDEX: generated by tools/port/index-decisions -- do not hand-edit -->
 
-316 sections. Search this before re-deriving anything.
+317 sections. Search this before re-deriving anything.
 
 * [P0 — the exporter, 2026-08-28](#p0--the-exporter-2026-08-28)
 * [P1 — Godot draws the screen, 2026-08-28](#p1--godot-draws-the-screen-2026-08-28)
@@ -327,6 +327,7 @@ dies, which is what this file is for.
 * [The number in my decision document was stale the moment I committed it](#the-number-in-my-decision-document-was-stale-the-moment-i-committed-it)
 * [A command without a pass condition is half a check](#a-command-without-a-pass-condition-is-half-a-check)
 * [What every failure this week actually was](#what-every-failure-this-week-actually-was)
+* [The remaining multi-leg claims audited — and the pattern I predicted is not there](#the-remaining-multi-leg-claims-audited--and-the-pattern-i-predicted-is-not-there)
 
 <!-- /INDEX -->
 ## P0 — the exporter, 2026-08-28
@@ -15491,3 +15492,32 @@ test.
 doing, not whether it is correct.** Every entry in the list above was caught by
 somebody asking that about somebody else's sentence — and in four of the five, the
 somebody was the other agent.
+
+## The remaining multi-leg claims audited — and the pattern I predicted is not there
+
+I have listed *"four unaudited multi-leg claims"* as open for several iterations,
+and after the week's findings I said I **expected the same inversion in them**: a
+count standing in for an exclusion argument. Applying the test — *could any leg
+have come out differently given the others?*
+
+| claim | verdict |
+|---|---|
+| `loop_start_why` — *"two derivations, neither converts bits to seconds"* | ✅ **holds.** (a) depends on a measured **rate**, (b) on the **cycle** — a wrong rate breaks (a) and leaves (b), a wrong cycle does the reverse. They fail **independently**. ⚠️ Bound: one trace, so they exclude arithmetic error and not trace error — which the existing *"one boot, one bank"* caveat already says |
+| `arithmetic_why` — *"the corpus had independently measured 28.5 fps"* | ✅ **holds.** A different quantity, measured **before** these runs, so it could have disagreed. It agrees to **1.4 %** |
+| `black_hold_why` — *"I checked independently…"* | ✅ **holds, and needed nothing** — it was already an exclusion argument: a constant excluded, outgoing-screen keying excluded, and four declared quantities each shown not to separate the pairs |
+
+📌 **So the prediction was wrong, and that is worth recording as loudly as a
+confirmation would have been.** Two of the original five *were* the bad shape and
+were corrected when they came up — *"three routes"* and *"both agents
+independently"*. The three that remained are sound, and **two of them were already
+exclusion arguments before I had the vocabulary for it.**
+
+⚠️ **The lesson I nearly drew was that my corpus is riddled with count-shaped
+support.** It is not: it had **two**, both relayed from a peer's message, and the
+claims I built from my own measurements state what they exclude. **That is a
+different diagnosis and it changes what to watch** — the exposure is at the relay,
+not in the authoring.
+
+✅ Each `why` now states **what its legs discriminate**, rather than how many there
+are. That is the whole content of the week's finding applied to my own data: *the
+count was never the claim.*