frank-primary: 2 x 200704 fp8, pool cut for the expert arena, MNBT 1024

The 2026-10-01 bf16 shape (2 x 262144, --expert-precise-memory)
crash-looped at graph capture — the arena is DEVICE-resident and that
shape had 0.13 GiB to spare. The plain bf16 2 x 262144 also did not stay
up: 0 bytes free at runtime, and a real client request (995-token prompt,
max_tokens=261149) killed the worker with .

The correction is a pool cut, not a downgrade. FP8 KV (7,701 B/token),
two 200704 windows (401,408 tokens -> 3.091e9 B floor, pinned 3.15e9),
MNBT 1024. The fork's expert planner sizes the arena AFTER the KV
override, so the ~2.95 GiB/rank reclaimed becomes arena: ~7,500 slots
vs 6,248. Two contexts at 200704 is a capacity contract, not a
throughput one (2-way concurrency summed BELOW parity at 4064 ctx), so
the slot buys the VRAM headroom long generations need.

Refs [[dankserver-qwen38-fp8-expert-offload-tuning]].

- scripts/frank-primary.env: MAXLEN 200704, SEQS 2, KV_BYTES 3.15e9,
  MNBT 1024, rewritten shape comment
- scripts/serve-frank-primary.sh: header comment updated
- tests/frank_primary_unit.bats: assertions updated, new seam pins the
  arena-floor pool law (the pool must move with a context change or the
  reduction buys nothing)
- docs + AGENTS.md: fleet topology and deployed shape corrected

tests/frank_primary_unit.bats

@@ -2,10 +2,11 @@
 # Seam: frank-primary — the Dankserver LLM endpoint on :7770.
 #
 # This file asserts the tcclaviger RDNA4 vLLM ROOT-UNIT shape (the
-# 2026-10-01 BF16 cutover, the overnight redo campaign's verdict): the serve
+# 2026-10-02 correction of the 2026-10-01 BF16 cutover): the serve
 # script drives `podman run` DIRECTLY (the image entrypoint execs
 # `vllm serve`), with every engine flag qualified by boot probe and carried
-# in the repo env file. The seam pins what the flags alone do not say: the
+# in the repo env file.
+# The seam pins what the flags alone do not say: the
 # KV qualification law (the night ladder: 262144/245760 OOM at graph
 # capture; 241664 boots at 732,359 tokens / 3.03x, util 0.98;
 # the bf16-KV trade (double the attention-KV bytes/token, ~14% decode cost,
@@ -91,29 +92,31 @@ DOWNLOAD="$REPO_ROOT/scripts/download-frank-primary.sh"
 
 @test "the qualified engine shape is in the env file" {
     # 2026-10-01 night ladder (Frank's method), then a runtime-survivability
-    # correction. SEQS=3 bf16 topped out at 241664 (KV 732,359 / 3.03x);
+    # correction, then Frank's 2026-10-02 decision to give the pool back to
+    # the expert arena. SEQS=3 bf16 topped out at 241664 (KV 732,359 / 3.03x);
     # SEQS=6 fp8 does NOT fit (6 x 241664 asked 10.70 GiB against 9.18 GiB
     # free); SEQS=5 fp8 x 262144 BOOTED (KV 1,350,182 / 5.15x) but left ~0
     # bytes free at runtime and a real client request (995-token prompt with
     # max_tokens=261149) killed the worker with `Tried to allocate 50.00 MiB
-    # ... 0 bytes free`. FOUR slots at the full native 262144 window is the
-    # deployed shape: ~1.93 GiB more headroom per rank for
-    # activations/graphs. UTIL stays 0.98 (lowering it shrinks the engine's
-    # own budget instead of buying slack).
-    # FINAL (2026-10-01, Frank): TWO full-size windows with BF16 KV plus
-    # --expert-precise-memory. bf16 costs 13,839 B/token (measured), so
-    # 2 x 262144 = 524,288 tokens needs 7.256e9 B; pinned at 7.3e9 (~527.5k
-    # tokens, 3,206 margin). The precise flag drops the plan's overhead
-    # 7.60 -> 5.25 GiB, moving the arena from 6,248 to ~7,278 slots.
-    grep -q '^FRANK_PRIMARY_MAXLEN=262144$' "$ENV_FILE"
-    grep -q '^FRANK_PRIMARY_SEQS=3$' "$ENV_FILE"
+    # ... 0 bytes free`. 200704 sits below the 241664 rung while leaving a
+    # full 2.95 GiB/rank to cut loose for the arena. UTIL stays 0.98
+    # (lowering it shrinks the engine's own budget instead of buying slack).
+    # FINAL (2026-10-02, Frank): TWO windows at 200704 with FP8 KV and a pool
+    # cut for the arena. fp8 costs 7,701 B/token (measured 6,138 attention +
+    # 1,563 mamba/side), so 2 x 200704 = 401,408 tokens needs 3.091e9 B;
+    # pinned at 3.15e9 (~405k tokens, ~44 MB margin). The arena is what
+    # remains — the planner sizes it AFTER the KV override — so the 6,248
+    # slots of the 6.1e9 shape become roughly 7,500 here.
+    grep -q '^FRANK_PRIMARY_MAXLEN=200704$' "$ENV_FILE"
+    grep -q '^FRANK_PRIMARY_SEQS=2$' "$ENV_FILE"
     grep -q '^FRANK_PRIMARY_UTIL=0.98$' "$ENV_FILE"
-    grep -q '^FRANK_PRIMARY_KV_BYTES=6100000000$' "$ENV_FILE"
-    grep -q '^FRANK_PRIMARY_MNBT=2048$' "$ENV_FILE"
+    grep -q '^FRANK_PRIMARY_KV_BYTES=3150000000$' "$ENV_FILE"
+    grep -q '^FRANK_PRIMARY_MNBT=1024$' "$ENV_FILE"
     grep -q '^FRANK_PRIMARY_KV_DTYPE=fp8$' "$ENV_FILE"
-    # --expert-precise-memory is NOT set: with bf16 2 x 262144 it put the boot
-    # 0.13 GiB from the 31.86 GiB ceiling (arena 16.65 device-resident) and
-    # crash-looped at graph capture. The serve script keeps the opt-in flag.
+    # --expert-precise-memory is NOT set: with bf16 2 x 262144 it put the
+    # boot 0.13 GiB from the 31.86 GiB ceiling (arena 16.65 device-resident)
+    # and crash-looped at graph capture. The serve script keeps the opt-in
+    # flag; the smaller pool here is the arena it would have been paying for.
     ! grep -q '^FRANK_PRIMARY_PRECISE_MEMORY=' "$ENV_FILE"
     grep -q '^FRANK_PRIMARY_GATHER_CHUNKS=32$' "$ENV_FILE"
     grep -q '^FRANK_PRIMARY_GATHER_LANES=64$' "$ENV_FILE"
@@ -121,6 +124,22 @@ DOWNLOAD="$REPO_ROOT/scripts/download-frank-primary.sh"
     grep -q '^FRANK_PRIMARY_MODEL_SHARDS=131$' "$ENV_FILE"
 }
 
+@test "the pool is sized as the arena floor, not the context floor" {
+    # THE LAW this seam pins: the fork's expert planner sizes the arena
+    # AFTER the KV override, so every byte cut out of KV_BYTES becomes
+    # arena. A context-size change must move the pool with it, or the
+    # reduction buys nothing. 2 x 200704 = 401,408 tokens at fp8's 7,701
+    # B/token is 3.091e9 B; the pin is 3.15e9, ~44 MB of margin above the
+    # floor — the same convention the 6.1e9 shape used.
+    floor=$(awk -v n="401408" -v b="7701" 'BEGIN{printf "%.0f", n*b}')
+    [ "$floor" = "3091243008" ]
+    kv=$(grep '^FRANK_PRIMARY_KV_BYTES=' "$ENV_FILE" | cut -d= -f2)
+    [ "$kv" = "3150000000" ]
+    margin=$(( kv - floor ))
+    [ "$margin" -gt 40000000 ]
+    [ "$margin" -lt 100000000 ]
+}
+
 @test "the serve script wires the engine flags from the env" {
     grep -q -- '--max-num-seqs "$FRANK_PRIMARY_SEQS"' "$SERVE"
     grep -q -- '--max-model-len "$FRANK_PRIMARY_MAXLEN"' "$SERVE"
@@ -208,13 +227,14 @@ DOWNLOAD="$REPO_ROOT/scripts/download-frank-primary.sh"
     grep -q -- '-e R4D_LRU_GATHER_CHUNKS="$FRANK_PRIMARY_GATHER_CHUNKS"' "$SERVE"
 }
 
-@test "MNBT is at Frank's 2048 with the arena intact" {
+@test "MNBT is at Frank's 1024 with the arena intact" {
     # MNBT 512 doubles TTFT at 4064 ctx (2.46 s vs 1.36 s); 1024-4096 are
     # interchangeable on decode AND identical on arena (the sweep measured
     # 6,499 slots at every rung <=4096); 12288 costs 2.5% plus arena.
-    # 2048 is Frank's setting as of 2026-10-01 — it keeps the workspace floor
-    # so the expert arena stays max.
-    grep -q '^FRANK_PRIMARY_MNBT=2048$' "$ENV_FILE"
+    # 1024 is the 2026-10-02 setting — the pool was cut to feed the expert
+    # arena, so the workspace floor matters more than it did at 2048: the
+    # arena budget is what is left, and 1024-4096 pay nothing for it.
+    grep -q '^FRANK_PRIMARY_MNBT=1024$' "$ENV_FILE"
     grep -q -- '--max-num-batched-tokens "$FRANK_PRIMARY_MNBT"' "$SERVE"
 }