re: THE DECREMENT IS MEASURED -- REMAINING OB is fully solved

SYLPH_WEAKEST=1 (00052b0) worked on its first live run: concentrating fire on the
already-damaged attacker produced the kill that four previous runs could not.

All gates enforced first -- FLIGHT confirmed, stage asserted, mission clock shown
advancing -- then:

  live e010 floor: 16 for samples 0-11, then 15 for samples 12-39 (one death)
  counter: 004 -> 008 at 02:06.33 (t=120 arrival, +4)
           008 -> 007 at 03:10.28  <-- DECREMENT, bracket (171.2s, 190.3s]
           007 -> 011 at 03:48.40 (t=210 arrival, +4 FROM 7, not from 8)
           011 held to 06:50.30 -- ceiling 11, where every prior run reached 12

Conclusive because: it fell by exactly 1 and not by 4, so the counter tracks CRAFT
not squadrons; exactly one attacker died and exactly one decrement occurred, in the
same window; and the CEILING moved with it -- a counter that merely read arrivals
would still have shown 012.  Control held: turrets fell 109 -> 92, seventeen
deaths, none of which moved it.

Settled reading: REMAINING OB is the number of objective-marked craft still alive,
the marked craft being exactly the members of the phase's A-route squadrons.  It
rises by a squadron's membership on that squadron's route arrival time and falls by
one per marked craft destroyed.  Every number was predicted from Route_S02.tbl and
UnitGroup_S02.tbl before it was measured.

docs/re/ob-counts-marked-attackers.md

@@ -1,9 +1,9 @@
 # 🟡 What `REMAINING OB` counts — the marked attackers, four per arriving squadron
 
-**Status: ✅ CONFIRMED for the counter's RISES — the `A`-route arrival times
-predict every step to the second (measured 2026-08-27, see below). 🟡 the
-DECREMENT half is still untested: no run has yet killed a marked attacker under
-observation.** It is recorded because it is the first reading that fits *every*
+**Status: ✅ CONFIRMED, both halves (2026-08-27).** The `A`-route arrival times
+predict every rise to the second, and a marked attacker's death was finally
+observed: the counter fell by **exactly one**, and the next arrival then raised
+it by four from the *reduced* value. See the final section. It is recorded because it is the first reading that fits *every*
 number this corpus has taken, and because it makes sharp predictions that one
 run can kill.
 
@@ -456,3 +456,63 @@ runs end early, so a 30-minute engagement on one target is not reachable.
   they were never deliberately used.
 * **Accept it as a long-run experiment** and check the counter after a scripted
   event kills an attacker, rather than trying to force one.
+
+---
+
+# ✅✅ THE DECREMENT, MEASURED — the hypothesis is confirmed in full
+
+The four previous attempts failed because fire was spread across the squadron:
+14 of 16 attackers damaged, none killed. `pilot.py` gained `SYLPH_WEAKEST=1`
+(commit `00052b0`), which scales a target's score by its remaining hull so the
+pilot finishes what is already hurt. It worked on the first live run.
+
+All gates enforced first: `FLIGHT` confirmed, stage asserted, mission clock shown
+advancing (00:10.12 → 00:23.14 → 00:36.30) before the experiment began.
+
+## The measurement
+
+Live `e010` count, logged every 10 s — the floor drops **once**, at sample 12,
+and stays down:
+
+```
+ 0..11  e010=16      (spikes to 18/20 are the known tool artifact)
+12..39  e010=15      one marked attacker dead
+```
+
+The counter, sampled beside the mission clock
+([capture](captures/ob-decrement-confirmed.png)):
+
+| mission `TIME` | `OB` | |
+|---|---|---|
+| 01:45.65 | `004` | |
+| **02:06.33** | **`008`** | the t=120 arrival, +4 |
+| 02:51.19 | `008` | |
+| **03:10.28** | **`007`** | **← DECREMENT, in (171.2 s, 190.3 s]** |
+| 03:29.66 | `007` | |
+| **03:48.40** | **`011`** | the t=210 arrival, +4 **from 7, not from 8** |
+| 04:07 → 06:50.30 | `011` | holds; ceiling is 11, not 12 |
+
+## Why this is conclusive and not a coincidence
+
+* **It fell by exactly 1**, not by 4. So the counter tracks *craft*, not
+  squadrons — the competing reading is dead.
+* **Exactly one attacker died and exactly one decrement occurred**, in the same
+  window.
+* **The ceiling moved with it.** The t=210 arrival added its four to **7**,
+  giving **011** — where every previous run reached **012**. A counter that
+  merely read arrivals would have shown 012 regardless. The reduced ceiling is
+  the kill still being remembered 3 minutes later.
+* **The control held throughout.** Turrets fell **109 → 92** — seventeen deaths —
+  across the same run, and not one of them moved the counter.
+
+## The settled reading
+
+`REMAINING OB` = **the number of objective-marked craft still alive**, where the
+marked craft are exactly the members of the phase's `A`-route squadrons
+(Stage 02 phase 1: `ADT102`, `ADT107`, `ADT113`, each `n = 4`). It rises by a
+squadron's membership as each arrives on its route's first-keyframe time, and
+falls by one for each marked craft destroyed. Turret and other non-marked deaths
+do not affect it.
+
+Every number in that sentence was predicted from `Route_S02.tbl` and
+`UnitGroup_S02.tbl` before being measured.