R-281: a ratchet, because "helps in all of them" survives the advice decaying

R-280 left the claim satisfiable by a gain of 0.2. The artifact now records how
many measurable packs clear their own noise -- reliable: {aboveNoise: 36, of: 38}
-- and the check refuses if that share falls. It may rise freely.

A ratchet rather than a threshold: any threshold here would be a number I chose,
and choosing one just under the current value is what produced MEASURABLE =
[15,85]. A share rather than a count, so widening admission cannot pay it off.

Proved three ways in worktrees: making focus fire actively bad fires the drift
check first, which is correct; making it unreliable and re-recording fires the
older claim at 37 of 38; and claiming a better past, 38 of 38, is refused by the
ratchet itself. The ratchet bites exactly where the old claim does not -- between
"still helps everywhere" and "helps as reliably as it did", which is where a slow
degradation lives.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/REVIEW_LOG.md

@@ -6539,3 +6539,37 @@ measurable pack — is satisfied by gains of 0.2, so it is a weaker sentence tha
 the band admitted only contested fights. If it should be a stronger claim, the place to
 strengthen it is the claim, not the admission rule; tightening admission to protect a claim
 is how the band got here.
+
+## R-281 — a ratchet, because "helps in all of them" survives the advice becoming useless
+
+R-280 left check-focus asserting that focus fire helps in every measurable pack, and that
+sentence is now satisfied by a gain of **0.2**. True, and thin: the advice could decay to
+nothing everywhere it is not already decisive and the guard would still pass.
+
+**The strengthening is a ratchet rather than a threshold.** The artifact records how many
+measurable packs showed a gain clearing their own noise — `reliable: { aboveNoise: 36, of:
+38 }` — and the check refuses if that SHARE falls. It may rise freely.
+
+A threshold here would be a number I chose, and choosing one to sit just under the current
+value is the move that produced `MEASURABLE = [15, 85]` in the first place. A ratchet has no
+chosen number in it: the bar is the measurement, and it moves only when the game does.
+
+**It is a share and not a count**, so it cannot be satisfied by admitting more packs — which
+matters, because R-280 just widened admission from 31 to 38 and a count-based ratchet would
+have been paid off by the widening.
+
+**Proved by trying it three ways**, in throwaway worktrees:
+
+- *Make focus fire actively bad* — target the healthiest enemy instead of the most hurt.
+  The drift check fires first and names four creatures, which is correct: any movement is
+  drift before it is anything else.
+- *Make it unreliable and re-record* — concentrate only half the time, then `--update`.
+  The older claim fires: focus fire now helps in 37 of 38, so the page's flat assertion is
+  already false and the ratchet is never reached.
+- *Leave the game alone and claim a better past* — set the recorded share to 38 of 38. The
+  ratchet refuses: *"clears its own noise in 36 of 38, down from 38 of 38 ... that is a
+  change in the game, not a baseline to refresh."*
+
+The middle case is the useful one to understand: **the ratchet only bites where the existing
+claim does not**, in the band between "still helps everywhere" and "helps as reliably as it
+did". That band is exactly where a slow degradation lives, and it was unguarded until now.