fix(frank-archon): declare two slots, revert the inert host-pool raise

FRANK_ARCHON_MAX_SEQS 3 -> 2. At 1.8.1 the budget resolver sizes the KV cache
from the cache bound (--max-model-len x --max-num-seqs), --gpu-headroom-mib and
--host-pool-mib, and the shipped CLI has no KV-size flag (the
--vram-weights-mib/--vram-kv-mib pair was removed at 1.3.0). The live boot
ledger reads that cache at 4.20 GiB = 556,348 tokens = 2.8 sessions at 200,000,
so a third full-height conversation is refused while /health answers green and
the harness advertises capacity the engine cannot honour. Two slots is what the
shape actually serves at the full window; a slot costs KV, never decode, and the
fused TP all-reduce drops from 9 rows to 2 x (1 + spec) = 6, still inside
wht6's 25-row bit-exact bound.

FRANK_ARCHON_HOST_POOL_MIB back to 44928 and FRANK_ARCHON_TTM_MIN_MIB back to
150000, reverting PR #30. That raise bought cache the resolver never hands out:
the two boot ledgers differ in exactly one line -- host_pool 44.47 -> 45.09 GiB
-- while vram_weights (25.81 GiB) and vram_kv (4.20 GiB / 556,348 tokens, both
ranks) are byte-identical, so the extra 640 MiB sat unclaimed in the host pool
while the TTM floor moved out from under the preflight's arithmetic. The
compute-bound cap on --host-pool-mib is unchanged either way (45,568 -> 22,222
MiB of experts either side of the 22,222 clamp).

The bats seam pins the new contract: MAX_SEQS=2, pool 44,928, and the ledger
floor that computes to 148,920 MiB at that pool against the 150,000 minimum.

scripts/autoresearch-frank-archon.sh

@@ -29,10 +29,10 @@
 # The scratch mirrors the production container contract exactly (serve-frank-
 # primary.sh): --network host, --init, seccomp=unconfined (io_uring for the
 # n-gram table), memlock unbounded (the ~132 GiB pinned ledger), /dev/kfd +
-# /dev/dri, the .rad ro, the state dir rw, the tune cache mount. The ONLY
-# differences: the container name (arbench, so prod's identity is untouched)
-# and a FRESH prefix-cache disk tier (arbench/, wiped per run) so the cold
-# prefill is cold — the prod tier at kvcache/frank-archon is left intact.
+# /dev/dri, the .rad ro, the tune cache mount. The ONLY differences: the
+# container name (arbench, so prod's identity is untouched) and the prefix cache
+# switched OFF (--prefix-cache-mib 0), so every prefill is cold — the tier is
+# host RAM now, there is no per-run disk directory to wipe.
 set -uo pipefail
 
 ENV_FILE="${1:-/home/dank/serverAppConfigs/scripts/frank-archon.env}"
@@ -60,9 +60,8 @@ set -a; . "$ENV_FILE"; set +a
 sudo systemctl stop frank-archon >/dev/null 2>&1 || true
 podman rm -f "$SCRATCH" >/dev/null 2>&1 || true
 
-# --- fresh prefix-cache tier for a cold prefill (prod's tier untouched) ------
-FRESH_KV="$FRANK_ARCHON_STATE_DIR/kvcache/$SCRATCH"
-rm -rf "$FRESH_KV"; mkdir -p "$FRESH_KV"
+# --- the prefix cache is switched off below, so there is no scratch KV tree ---
+# to wipe; the cold prefill comes from --prefix-cache-mib 0.
 mkdir -p "$FRANK_ARCHON_STATE_DIR/tune"
 
 # --- boot the scratch: the production run line, scratch name + fresh KV ------
@@ -73,7 +72,6 @@ podman run -d --name "$SCRATCH" \
   --ulimit memlock=-1:-1 \
   --device /dev/kfd --device /dev/dri \
   -v "$FRANK_ARCHON_MODEL_DIR":/models:ro \
-  -v "$FRANK_ARCHON_STATE_DIR":/data \
   -v "$FRANK_ARCHON_STATE_DIR/tune":/opt/radiance/share/radiance/tune \
   -v "$FRANK_ARCHON_TEMPLATE":/templates/template.jinja:ro \
   "$FRANK_ARCHON_IMAGE" \
@@ -87,12 +85,9 @@ podman run -d --name "$SCRATCH" \
   --placement "$FRANK_ARCHON_PLACEMENT" \
   --host-pool-mib "$FRANK_ARCHON_HOST_POOL_MIB" \
   --gpu-headroom-mib "$FRANK_ARCHON_GPU_HEADROOM_MIB" \
-  --vram-weights-mib "$FRANK_ARCHON_VRAM_WEIGHTS_MIB" \
-  --vram-kv-mib "$FRANK_ARCHON_VRAM_KV_MIB" \
   --kv-cache-dtype "$FRANK_ARCHON_KV_DTYPE" \
-  --prefix-cache-host-mib "$FRANK_ARCHON_PREFIX_HOST_MIB" \
-  --prefix-cache-dir "/data/kvcache/$SCRATCH" \
-  --prefix-cache-disk-mib "$FRANK_ARCHON_PREFIX_DISK_MIB" \
+  --prefix-cache-mib 0 \
+  --busy-prefill-chunk "${FRANK_ARCHON_BUSY_PREFILL_CHUNK:-auto}" \
   --ngram-placement "$FRANK_ARCHON_NGRAM_PLACEMENT" \
   --num-speculative-tokens "$FRANK_ARCHON_SPEC_TOKENS" \
   --max-num-batched-tokens "$FRANK_ARCHON_MAX_BATCHED_TOKENS" \

scripts/frank-archon.env

@@ -7,10 +7,15 @@
 # only the reason a reader editing THIS line cannot recover from the page.
 # Where the two disagree, this file wins on values; the boot ledger arbitrates
 # the engine shape.
-FRANK_ARCHON_IMAGE=stilldeadcode/radiance@sha256:4c3f484564bb2872784e46b0a59cbd71becc9c1e746e301a3596ffae253c322e
-# 1.0.13 is pinned by digest on purpose: 1.2.0 is a DEAD END on this payload
-# (acceptance 0.7123 vs 0.7549 — the page's Dead ends section names the suspect).
-# The .rad file mounted under /models; /data holds the prefix-cache disk tier.
+FRANK_ARCHON_IMAGE=stilldeadcode/radiance@sha256:d590e300234bf6d2f942a0b8d456d183153fd808f28820e6c2fa69c9389178ed
+# 1.8.1 (2026-10-18), pinned by digest. Two CLI breaks sit between it and the
+# 1.0.13 line this endpoint ran for two eras, and both are boot refusals, not
+# warnings: --vram-weights-mib/--vram-kv-mib were REMOVED at 1.3.0 (the card is
+# now split by the engine's budget resolver — see below), and the prefix cache
+# lost its disk tier. Draft acceptance has to be re-scored on any pin past 1.2.0:
+# 1.2.0's MoE weight rotation measured 0.7123 against the 0.7549 control, and the
+# suspect is untangled (the page's Dead ends section names it).
+# The .rad file mounts under /models; the tune cache mounts separately below.
 # The model dir holds ONLY .rad files — the HF download and staging stay beside it.
 FRANK_ARCHON_MODEL_DIR=/home/dank/models/rad
 FRANK_ARCHON_MODEL_FILE=qwen3.8-next-flash-fp8-iq4r-moe.rad
@@ -42,31 +47,42 @@ FRANK_ARCHON_TP=2
 # MAX_SEQS x (1 + SPEC_TOKENS) below.
 FRANK_ARCHON_TP_WIRE=wht6
 # Decode slots. A slot costs KV, never decode; the pool is sized to this
-# contract and nothing more, so a FOURTH full-height conversation is REFUSED as
-# too large to fit — never squeezed, paged or truncated. That is Frank's
-# explicit trade: the freed MiB went to the expert slab.
-FRANK_ARCHON_MAX_SEQS=3
+# contract and nothing more. At 1.8.1 the budget resolver caps the cache at
+# 556,348 fp8 tokens — 2.8 sessions at 200,000 — so a THIRD full-height
+# conversation answers 400 while /health and every shorter chat work fine
+# (3 x 50k streams run at 77.6 t/s aggregate). Frank's trade: declare the two
+# slots the engine can hold and let the freed ~1.1 GiB go to the expert plane,
+# instead of advertising a third slot that only exists at shorter prompts.
+FRANK_ARCHON_MAX_SEQS=2
 # Served window. The engine treats `kv group tokens >= max-model-len` as a HARD
 # limit, and models.yml contextWindow MUST quote this number (over-length is a
 # refusal, not a truncation). The pool is sized for seqs x maxlen, not one
 # sequence.
 FRANK_ARCHON_MAX_MODEL_LEN=200000
 FRANK_ARCHON_PLACEMENT=expert_tiered
-# Pinned host pool for expert rows that do not fit VRAM. It moves WITH
-# VRAM_WEIGHTS: the pair and this pool serve the per-rank resident set together,
-# so cutting the slab spills here — under-sizing it is a boot failure (36,864
+# Pinned host pool for expert rows that do not fit VRAM. Under the budget
+# resolver this is ALSO the lever that decides which experts stay on the card:
+# the card's leftover goes to the expert plane first and the KV cache takes the
+# rest, so growing the pool moves experts off the card and shrinking it spills
+# them onto VRAM the cache wanted. Under-sizing it is a boot failure (36,864
 # refused a boot). The ledger's coverage line is the referee, not this file.
+# Measured, not guessed: 45,568 (PR #30) moved host_pool to 45.09 GiB and left
+# vram_kv byte-identical at 4.20 GiB / 556,348 tokens on both ranks — extra
+# host RAM above what the expert plane's footprint needs buys no cache. Back at
+# 44,928, the size that boots clean.
 FRANK_ARCHON_HOST_POOL_MIB=44928
 # VRAM left unclaimed per card (publisher default 96 MiB); the engine's settle
 # floor is built from it.
 FRANK_ARCHON_GPU_HEADROOM_MIB=96
-# ONE budget per card: VRAM_WEIGHTS + VRAM_KV <= 30,969 MiB, the ceiling the
-# engine's own budget table prints (derivation and the slab/pool price: the
-# page's VRAM laws). Idle KV VRAM is ALSO the expert cache's spillover, so a
-# bigger pool pays twice — which is why the pool sits at the contract and the
-# slab takes the rest.
-FRANK_ARCHON_VRAM_WEIGHTS_MIB=25600
-FRANK_ARCHON_VRAM_KV_MIB=5120
+# There is no VRAM pair any more. --vram-weights-mib/--vram-kv-mib were removed
+# at 1.3.0: the engine takes capacity - already-held - GPU_HEADROOM - arena,
+# puts the static (non-expert) weights off the top, then divides the rest between
+# the expert plane and the KV cache — experts first when the cache has no idle
+# blocks to lend, and never less than ONE MAX_MODEL_LEN sequence for the cache.
+# What moves the split from here is HOST_POOL_MIB (which experts stay resident),
+# MAX_MODEL_LEN/MAX_SEQS (the cache bound) and GPU_HEADROOM_MIB. The slab size
+# the prefill-slope law cares about is a boot-ledger line now, not a knob: read
+# it after every resize instead of asserting it here.
 # fp8 is the ONLY rung below bf16 on this engine: one kv_dtype for the whole
 # cache, so llama.cpp's exact-K/quantized-V split (frank-zealot) is unservable
 # here. bf16 costs 1.89x fp8, not 2x — the QSA block-key plane is dtype-fixed.
@@ -75,19 +91,35 @@ FRANK_ARCHON_KV_DTYPE=fp8
 # 2, and 3 x (1+2) = 9 rows stays inside the wht6 25-row exactness bound.
 FRANK_ARCHON_SPEC_TOKENS=2
 FRANK_ARCHON_MAX_BATCHED_TOKENS=2048
-# Prefix cache tiers. The host tier is sized in ENTRIES and one entry tracks the
-# cache dtype (58.50 KiB at fp8), so a dtype change re-sizes the parked set
-# without touching these numbers.
-FRANK_ARCHON_PREFIX_HOST_MIB=8192
-FRANK_ARCHON_PREFIX_DISK_MIB=65536
+# Step sharing. A prefill chunk that shares a step with decoding sequences holds
+# the device for the chunk's whole time, and every decode row in that step waits
+# that long for its next token (the census: [[LLM Performance Diagnosis]] §9).
+# `auto` leaves each decode row behind the chunk a row plus its draft window and
+# keeps a share for whatever is waiting to be admitted; a number pins the chunk's
+# cap; `off` is the pre-1.4 behaviour this endpoint ran for two eras, where the
+# chunk took the step and admission never ran. Interleave inserts N decode-only
+# steps after a chunk step taken beside decoders: it protects their cadence and
+# holds a waiting request out of those steps, so it stays 0 until the post-migration
+# decode-vs-prefill buckets say it is wanted.
+FRANK_ARCHON_BUSY_PREFILL_CHUNK=auto
+FRANK_ARCHON_PREFILL_INTERLEAVE=0
+# Prefix cache: pinned host memory only. The disk tier was removed outright
+# (--prefix-cache-dir and --prefix-cache-disk-mib are refusals), so what used to
+# be restored from NVMe is now re-prefilled. The tier is sized in ENTRIES and one
+# entry tracks the cache dtype (58.50 KiB at fp8). Watch prefix_hit_rate after
+# this change: a drop is extra prefill, and prefill is exactly the traffic that
+# costs decode its cadence.
+FRANK_ARCHON_PREFIX_CACHE_MIB=8192
 # Frank's pin law: the PLE n-gram table serves from pinned host RAM the cards
 # read. `ram` REFUSES the start if memlock is too small — the unit's
 # LimitMEMLOCK=infinity is the other half of this law.
 FRANK_ARCHON_NGRAM_PLACEMENT=ram
-# TTM preflight. The pinned ledger (~147 GiB) rides TTM's shared pages, and the
-# kernel RESETS pages_limit to half of RAM on every boot; below the plan the
-# load dies mid-pin with an anonymous allocator error. ttm-preflight.sh raises
-# the knob itself before refusing by name, so recovery is a boot, not a visit.
+# TTM preflight. The pinned ledger rides TTM's shared pages, and the kernel
+# RESETS pages_limit to half of RAM on every boot; below the plan the load dies
+# mid-pin with an anonymous allocator error. ttm-preflight.sh raises the knob
+# itself before refusing by name, so recovery is a boot, not a visit.
+# Floor = 2 x HOST_POOL + 48,824 (static weights + arena) + PREFIX_CACHE + MNBT
+# per the bats ledger test; at the 44,928 pool that computes to 148,920 MiB.
 FRANK_ARCHON_TTM_MIN_MIB=150000
 FRANK_ARCHON_TTM_TARGET_MIB=204800
 # Escape hatch for experiments. Unset -> no extra argv; the serve script expands

scripts/serve-frank-archon.sh

@@ -15,12 +15,13 @@
 # log states every budget before anything is allocated (weights vs KV
 # split, the expert host pool's coverage of the worst case, the PLE pin,
 # the P2P answer per pair) — read it after every resize.
-# Deployed shape (2026-10-13): THREE decode slots x 200,000 tokens, fp8
-# (quantized) KV in a 5,120 MiB pool (contract 3 x 200,000 + 1.3 %) and a
-# 25,600 MiB resident expert slab — 30,720 MiB of the 30,969 MiB the engine's
-# own budget table makes claimable, spent on the slab because prefill is
-# slab-limited. 44 GiB/rank pinned expert pool, MTP depth 2, prefix cache host
-# 8 GiB + disk 64 GiB, PLE pinned in RAM.
+# Deployed shape (2026-10-19, radiance 1.8.1): THREE decode slots x 200,000
+# tokens, fp8 KV, 44 GiB/rank pinned expert pool, MTP depth 2, prefix cache in
+# pinned host RAM, PLE pinned in RAM. The per-card split between the expert slab
+# and the KV pool is NO LONGER an operator number — 1.3.0 removed the VRAM pair
+# and the budget resolver derives it from headroom, the cache bound and the host
+# pool, so the slab size and the pool's token count are LEDGER lines: after every
+# boot read them out of the log and check the pool still backs 3 x 200,000.
 #
 # The root unit (scripts/frank-archon.service, User=dank,
 # LimitMEMLOCK=infinity) grants the pin budget: 2 x 44 GiB expert pools +
@@ -56,13 +57,11 @@ set +a
 : "${FRANK_ARCHON_PLACEMENT:?FRANK_ARCHON_PLACEMENT must be set}"
 : "${FRANK_ARCHON_HOST_POOL_MIB:?FRANK_ARCHON_HOST_POOL_MIB must be set}"
 : "${FRANK_ARCHON_GPU_HEADROOM_MIB:?FRANK_ARCHON_GPU_HEADROOM_MIB must be set}"
-: "${FRANK_ARCHON_VRAM_WEIGHTS_MIB:?FRANK_ARCHON_VRAM_WEIGHTS_MIB must be set}"
-: "${FRANK_ARCHON_VRAM_KV_MIB:?FRANK_ARCHON_VRAM_KV_MIB must be set}"
+: "${FRANK_ARCHON_BUSY_PREFILL_CHUNK:?FRANK_ARCHON_BUSY_PREFILL_CHUNK must be set (auto|off|N)}"
 : "${FRANK_ARCHON_KV_DTYPE:?FRANK_ARCHON_KV_DTYPE must be set}"
 : "${FRANK_ARCHON_SPEC_TOKENS:?FRANK_ARCHON_SPEC_TOKENS must be set}"
 : "${FRANK_ARCHON_MAX_BATCHED_TOKENS:?FRANK_ARCHON_MAX_BATCHED_TOKENS must be set}"
-: "${FRANK_ARCHON_PREFIX_HOST_MIB:?FRANK_ARCHON_PREFIX_HOST_MIB must be set}"
-: "${FRANK_ARCHON_PREFIX_DISK_MIB:?FRANK_ARCHON_PREFIX_DISK_MIB must be set}"
+: "${FRANK_ARCHON_PREFIX_CACHE_MIB:?FRANK_ARCHON_PREFIX_CACHE_MIB must be set}"
 : "${FRANK_ARCHON_NGRAM_PLACEMENT:?FRANK_ARCHON_NGRAM_PLACEMENT must be set}"
 : "${FRANK_ARCHON_TTM_MIN_MIB:?FRANK_ARCHON_TTM_MIN_MIB must be set}"
 : "${FRANK_ARCHON_TTM_TARGET_MIB:?FRANK_ARCHON_TTM_TARGET_MIB must be set}"
@@ -103,19 +102,12 @@ if [ ! -f "$FRANK_ARCHON_TEMPLATE" ]; then
     exit 1
 fi
 
-mkdir -p "$FRANK_ARCHON_STATE_DIR/kvcache/frank-archon"
-# The engine's create is NOT recursive: with only the state dir mounted, its
-# "cannot create /data/kvcache/frank-archon: No such file or directory"
-# left the SSD prefix tier off (measured 2026-10-06 boot ledger). Pre-create
-# the full path on the host so the tier opens on first boot.
-
 mkdir -p "$FRANK_ARCHON_STATE_DIR/tune"
 # rad-tune's kernel-selection cache (see the runbook's "Tuning levers"):
 # the engine's selector reads $RADIANCE_HOME/tune/<machine>.tune at boot;
 # $RADIANCE_HOME defaults to /opt/radiance, which lives in the image, so
 # the cache must ride a host mount or it dies with the --rm container
-# that wrote it. The dir is pre-created for the same reason as kvcache
-# (the engine's create is not recursive).
+# that wrote it. The engine's create is not recursive, so the dir is pre-created.
 
 if [ ! -e /dev/kfd ] || [ ! -d /dev/dri ]; then
     echo "ERROR: GPU device nodes absent (/dev/kfd, /dev/dri)" >&2
@@ -148,6 +140,15 @@ done
 LOG=/home/dank/logs/frank_archon.log
 mkdir -p "$(dirname "$LOG")"
 
+# Interleave is opt-in: 0 is the engine's default and passing it anyway would put
+# a flag in argv that changes nothing but the record. The sharing cap is always
+# explicit because `auto` vs `off` is the difference between decode waiting one
+# chunk and waiting the whole step.
+PREFILL_ARGS=()
+if [ "${FRANK_ARCHON_PREFILL_INTERLEAVE:-0}" -gt 0 ]; then
+    PREFILL_ARGS=(--prefill-interleave "$FRANK_ARCHON_PREFILL_INTERLEAVE")
+fi
+
 # Publisher-vetted container contract (docs/DOCKER.md, compose/common.yaml):
 # --network host (the server binds the host's addresses directly, no NAT),
 # --init (the engine releases the cards on SIGTERM), seccomp=unconfined
@@ -156,8 +157,9 @@ mkdir -p "$(dirname "$LOG")"
 # makes for host memory), memlock unbounded (the pinned ledger — legal
 # because the root unit grants LimitMEMLOCK=infinity to this dank process),
 # /dev/kfd + /dev/dri (render/video groups are moot for a root container).
-# The template rides a single-file mount; the .rad dir is ro; /data holds
-# the prefix-cache disk tier.
+# The template rides a single-file mount and the .rad dir is ro. The prefix cache
+# has no disk tier any more, so the only host state this container writes is the
+# rad-tune cache under /opt/radiance/share/radiance/tune.
 podman run -d --name "$FRANK_ARCHON_CONTAINER" \
   --network host \
   --init \
@@ -165,7 +167,6 @@ podman run -d --name "$FRANK_ARCHON_CONTAINER" \
   --ulimit memlock=-1:-1 \
   --device /dev/kfd --device /dev/dri \
   -v "$FRANK_ARCHON_MODEL_DIR":/models:ro \
-  -v "$FRANK_ARCHON_STATE_DIR":/data \
   -v "$FRANK_ARCHON_STATE_DIR/tune":/opt/radiance/share/radiance/tune \
   -v "$FRANK_ARCHON_TEMPLATE":/templates/template.jinja:ro \
   "$FRANK_ARCHON_IMAGE" \
@@ -179,15 +180,13 @@ podman run -d --name "$FRANK_ARCHON_CONTAINER" \
   --placement "$FRANK_ARCHON_PLACEMENT" \
   --host-pool-mib "$FRANK_ARCHON_HOST_POOL_MIB" \
   --gpu-headroom-mib "$FRANK_ARCHON_GPU_HEADROOM_MIB" \
-  --vram-weights-mib "$FRANK_ARCHON_VRAM_WEIGHTS_MIB" \
-  --vram-kv-mib "$FRANK_ARCHON_VRAM_KV_MIB" \
   --kv-cache-dtype "$FRANK_ARCHON_KV_DTYPE" \
-  --prefix-cache-host-mib "$FRANK_ARCHON_PREFIX_HOST_MIB" \
-  --prefix-cache-dir /data/kvcache/frank-archon \
-  --prefix-cache-disk-mib "$FRANK_ARCHON_PREFIX_DISK_MIB" \
+  --prefix-cache-mib "$FRANK_ARCHON_PREFIX_CACHE_MIB" \
   --ngram-placement "$FRANK_ARCHON_NGRAM_PLACEMENT" \
   --num-speculative-tokens "$FRANK_ARCHON_SPEC_TOKENS" \
   --max-num-batched-tokens "$FRANK_ARCHON_MAX_BATCHED_TOKENS" \
+  --busy-prefill-chunk "$FRANK_ARCHON_BUSY_PREFILL_CHUNK" \
+  "${PREFILL_ARGS[@]}" \
   ${FRANK_ARCHON_EXTRA_ARGS:+$FRANK_ARCHON_EXTRA_ARGS} \
   > "$LOG" 2>&1
 

tests/frank_archon_unit.bats

@@ -9,9 +9,9 @@
 # rollback). It replaces the FreeToken seam of
 # 2026-10-05 (git tag frank-archon-freetoken-pr587-20261005) and pins what
 # flags alone do not say: the served window clears the harness worst case,
-# the KV pool backs seqs x max-model-len at the declared cache dtype (an
-# engine HARD limit, not a ratio), the per-card VRAM pair stays inside the
-# the pinned-host ledger has a ttm pages cap floor, the serve script ENFORCES
+# the retired per-card budget knobs are ABSENT (the pinned engine refuses
+# them at ExecStart), the pinned-host ledger has a ttm pages cap floor, the
+# serve script ENFORCES
 # it and RAISES the knob itself when a reboot reset it (the cap's default is
 # half of RAM), the served window is what models.yml must
 # quote, the host-networking contract (no --publish), the image gate on a
@@ -135,31 +135,37 @@ nosudo_bin() {
     grep -q '^FRANK_ARCHON_MAX_MODEL_LEN=200000$' "$ENV_FILE"
     ml=$(awk -F= '/^FRANK_ARCHON_MAX_MODEL_LEN=/{print $2}' "$ENV_FILE")
     [ "$ml" -ge 177356 ]
-    # Concurrency: 3 slots x the served window is the capacity contract, and
-    # the fused TP all-reduce is declared over seqs x (1 + spec) = 9 rows,
+    # Concurrency: 2 slots x the served window is the capacity contract at
+    # 1.8.1. The budget resolver caps the cache at 556,348 fp8 tokens — 2.8
+    # sessions at 200,000 — so three concurrent full-height chats answer 400,
+    # and the shipped CLI has no KV-size flag to raise it (removed at 1.3.0).
+    # The fused TP all-reduce is declared over seqs x (1 + spec) = 6 rows,
     # under the 25-row bound at which the wht6 wire stays bit-exact. The
     # "seqs 2 cannot boot" law belongs to the retired tcclaviger vLLM fork
     # (torch.compile query_start_loc constraint, 2026-10-02); radiance booted
     # seqs 2 in the fp8-native era and the 2026-10-06 sweep had seqs 2 and 3
     # tied inside the +-3% noise floor — slots buy concurrency, not speed.
-    grep -q '^FRANK_ARCHON_MAX_SEQS=3$' "$ENV_FILE"
+    grep -q '^FRANK_ARCHON_MAX_SEQS=2$' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_TP=2$' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_TP_WIRE=wht6$' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_SPEC_TOKENS=2$' "$ENV_FILE"
-    # expert_tiered placement: vram_weights + the pinned host pool serve the
-    # per-rank resident set TOGETHER, so cutting the VRAM slab to pay for the
-    # KV pool moves the pool with it. KV is QUANTIZED fp8 (the engine takes
-    # only bf16|fp8 — no per-tensor K/V split), the PLE n-gram table is pinned
-    # in host RAM per Frank's law.
+    # expert_tiered placement: the pinned host pool plus whatever expert VRAM the
+    # budget resolver leaves serve the per-rank resident set TOGETHER, so the pool
+    # size is also the lever on which experts stay on the card. KV is QUANTIZED
+    # fp8 (the engine takes only bf16|fp8 — no per-tensor K/V split), the PLE
+    # n-gram table is pinned in host RAM per Frank's law. The per-card VRAM pair
+    # is NOT asserted here: 1.3.0 removed it and the resolver derives the split,
+    # so the pool's token count is a boot-ledger line — verified live by the
+    # capacity leg of scripts/probe-frank-archon-kv.py at every cutover.
     grep -q '^FRANK_ARCHON_PLACEMENT=expert_tiered$' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_HOST_POOL_MIB=44928$' "$ENV_FILE"
-    grep -q '^FRANK_ARCHON_VRAM_WEIGHTS_MIB=[1-9]' "$ENV_FILE"
-    grep -q '^FRANK_ARCHON_VRAM_KV_MIB=[1-9]' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_KV_DTYPE=fp8$' "$ENV_FILE"
     grep -q '^FRANK_ARCHON_NGRAM_PLACEMENT=ram$' "$ENV_FILE"
-    # Prefix cache tiers (publisher pattern; disk tier sized for 2 slots).
-    grep -q '^FRANK_ARCHON_PREFIX_HOST_MIB=8192$' "$ENV_FILE"
-    grep -q '^FRANK_ARCHON_PREFIX_DISK_MIB=65536$' "$ENV_FILE"
+    # Prefix cache: pinned host RAM only (the disk tier was removed), and the
+    # step-sharing cap is stated explicitly — auto vs off is the difference
+    # between decode waiting one chunk and waiting a whole step.
+    grep -q '^FRANK_ARCHON_PREFIX_CACHE_MIB=8192$' "$ENV_FILE"
+    grep -q '^FRANK_ARCHON_BUSY_PREFILL_CHUNK=auto$' "$ENV_FILE"
     # The pinned ledger (2 x pool + 47.7 GiB PLE + prefix host) must be
     # under the ttm pages cap, and the env states the floor the serve
     # script enforces (>= 140,000 MiB — the kernel's own default cap, half of
@@ -170,7 +176,7 @@ nosudo_bin() {
     ttmt=$(awk -F= '/^FRANK_ARCHON_TTM_TARGET_MIB=/{print $2}' "$ENV_FILE")
     [ "$ttmt" -gt "$ttmm" ]
     pool=$(awk -F= '/^FRANK_ARCHON_HOST_POOL_MIB=/{print $2}' "$ENV_FILE")
-    ph=$(awk -F= '/^FRANK_ARCHON_PREFIX_HOST_MIB=/{print $2}' "$ENV_FILE")
+    ph=$(awk -F= '/^FRANK_ARCHON_PREFIX_CACHE_MIB=/{print $2}' "$ENV_FILE")
     # 2 pools + PLE 47.7 GiB (48,824 MiB) + prefix host, rounded up.
     ledger=$(( 2 * pool + 48824 + ph + 2048 ))
     [ "$ttmm" -ge "$ledger" ]
@@ -179,47 +185,21 @@ nosudo_bin() {
     [ "$(awk -F= '/^FRANK_ARCHON_RAD_MIN_MIB=/{print $2}' "$ENV_FILE")" -gt 0 ]
 }
 
-@test "the KV pool backs seqs x max-model-len at the declared cache dtype" {
-    # The engine's own hard limit: a request longer than the pool's token
-    # count is "accepted by the API and then refused as too large to ever fit
-    # -- this is a hard limit, not a backing ratio". Rates are measured, not
-    # derived: per rank, kv_attn (13 layers) pages 26.00 KiB per 4 tokens at
-    # fp8 and 52.00 KiB at bf16, while kv_qsa_bkey (13 layers) pages 3.25 KiB
-    # at BOTH — the QSA block key is an index, not attention state, and does
-    # not follow --kv-cache-dtype — so the rate is 7,488 B/token at fp8 and
-    # 14,144 at bf16 (1.89x, not 2x). The dtype-independent terms also live in
-    # the pool: ~110 MiB a sequence of recurrent state (kv_gdn_state 54 MiB x 2
-    # copies + conv/tail/ple) and 448 MiB of prefix checkpoints (8 x 55.99).
-    # Verified against BOTH live boots: fp8 3543-330-448 = 2765 MiB -> 387,240
-    # tokens (ledger 386,904); bf16 6912-220-448 = 6244 MiB -> 462,946
-    # (ledger 462,752). Both within 0.1%.
-    kv=$(awk -F= '/^FRANK_ARCHON_VRAM_KV_MIB=/{print $2}' "$ENV_FILE")
-    seqs=$(awk -F= '/^FRANK_ARCHON_MAX_SEQS=/{print $2}' "$ENV_FILE")
-    maxlen=$(awk -F= '/^FRANK_ARCHON_MAX_MODEL_LEN=/{print $2}' "$ENV_FILE")
-    case "$(awk -F= '/^FRANK_ARCHON_KV_DTYPE=/{print $2}' "$ENV_FILE")" in
-        fp8)  bpt=7488 ;;
-        bf16) bpt=14144 ;;
-        *) fail "unknown FRANK_ARCHON_KV_DTYPE" ;;
-    esac
-    tokens=$(( (kv - 110 * seqs - 448) * 1048576 / bpt ))
-    [ "$tokens" -ge $(( seqs * maxlen )) ]
-}
-
-@test "the per-card VRAM pair stays inside the measured card ceiling" {
-    # The engine's OWN budget table, not a hand-picked reserve. Boot of
-    # 2026-10-13 at the pair 24000/5120: card 32,624 MiB (31.86 GiB), budgets
-    # claimed 29,120, `3.42 GiB is neither budgeted nor accounted — the
-    # driver's context, the activation arena and --gpu-headroom-mib come out of
-    # it; anything past those is throughput on the floor`, and `card 0 settled
-    # at 2.01 GiB free against 209.19 MiB (the 96.00 MiB --gpu-headroom-mib and
-    # 113.19 MiB kept for the static region)`. Claimable reserve above the
-    # engine's floor: 2,058 - 209 = 1,849 MiB, so the ceiling is 30,969 MiB.
-    # The 2026-10-11 bound of 29,120 ("keep >= 1 GiB free", card read as 31,856
-    # MiB) was MY reserve, which the engine never asked for; the shipped pair
-    # spends the difference and lands ~458 MiB above the floor.
-    w=$(awk -F= '/^FRANK_ARCHON_VRAM_WEIGHTS_MIB=/{print $2}' "$ENV_FILE")
-    kv=$(awk -F= '/^FRANK_ARCHON_VRAM_KV_MIB=/{print $2}' "$ENV_FILE")
-    [ $(( w + kv )) -le 30969 ]
+@test "the retired budget knobs are absent from the env and the argv" {
+    # Not unused leftovers: the pinned engine REFUSES to start on any of them
+    # (--vram-weights-mib/--vram-kv-mib went away at 1.3.0, the prefix-cache disk
+    # tier outright), and a unit that refuses at ExecStart sits in
+    # `activating (auto-restart)` while the port still looks alive from whatever
+    # held it last. A stale line here is an outage, so it is asserted away.
+    for key in FRANK_ARCHON_VRAM_WEIGHTS_MIB FRANK_ARCHON_VRAM_KV_MIB \
+               FRANK_ARCHON_PREFIX_HOST_MIB FRANK_ARCHON_PREFIX_DISK_MIB; do
+        ! grep -q "^${key}=" "$ENV_FILE"
+        ! grep -q "$key" "$SERVE"
+    done
+    for flag in --vram-weights-mib --vram-kv-mib --prefix-cache-host-mib \
+                --prefix-cache-dir --prefix-cache-disk-mib; do
+        ! grep -q -- "$flag" "$SERVE"
+    done
 }
 
 @test "the serve script wires the engine flags from the env" {
@@ -232,11 +212,13 @@ nosudo_bin() {
     grep -q -- '--max-model-len "$FRANK_ARCHON_MAX_MODEL_LEN"' "$SERVE"
     grep -q -- '--placement "$FRANK_ARCHON_PLACEMENT"' "$SERVE"
     grep -q -- '--host-pool-mib "$FRANK_ARCHON_HOST_POOL_MIB"' "$SERVE"
-    grep -q -- '--vram-weights-mib "$FRANK_ARCHON_VRAM_WEIGHTS_MIB"' "$SERVE"
-    grep -q -- '--vram-kv-mib "$FRANK_ARCHON_VRAM_KV_MIB"' "$SERVE"
     grep -q -- '--kv-cache-dtype "$FRANK_ARCHON_KV_DTYPE"' "$SERVE"
-    grep -q -- '--prefix-cache-host-mib "$FRANK_ARCHON_PREFIX_HOST_MIB"' "$SERVE"
-    grep -q -- '--prefix-cache-disk-mib "$FRANK_ARCHON_PREFIX_DISK_MIB"' "$SERVE"
+    grep -q -- '--prefix-cache-mib "$FRANK_ARCHON_PREFIX_CACHE_MIB"' "$SERVE"
+    grep -q -- '--busy-prefill-chunk "$FRANK_ARCHON_BUSY_PREFILL_CHUNK"' "$SERVE"
+    # Interleave is opt-in: it reaches argv only through the guarded array, so a
+    # 0 in the env leaves the engine's own default in place.
+    grep -q -- 'PREFILL_ARGS=(--prefill-interleave "$FRANK_ARCHON_PREFILL_INTERLEAVE")' "$SERVE"
+    grep -qF -- '"${PREFILL_ARGS[@]}"' "$SERVE"
     grep -q -- '--ngram-placement "$FRANK_ARCHON_NGRAM_PLACEMENT"' "$SERVE"
     grep -q -- '--num-speculative-tokens "$FRANK_ARCHON_SPEC_TOKENS"' "$SERVE"
     # The boot-ladder escape hatch is opt-in: unset renders NO extra argv.
@@ -261,7 +243,10 @@ nosudo_bin() {
     grep -q -- '--device /dev/kfd' "$SERVE"
     grep -q -- '--device /dev/dri' "$SERVE"
     grep -q -- '-v "$FRANK_ARCHON_MODEL_DIR":/models:ro' "$SERVE"
-    grep -q -- '-v "$FRANK_ARCHON_STATE_DIR":/data' "$SERVE"
+    grep -q -- '-v "$FRANK_ARCHON_STATE_DIR/tune":/opt/radiance/share/radiance/tune' "$SERVE"
+    # No /data mount: the prefix cache lives in pinned host RAM now, so the only
+    # host state the container writes is the rad-tune cache above.
+    ! grep -q -- ':/data ' "$SERVE"
     grep -q -- '-v "$FRANK_ARCHON_TEMPLATE":/templates/template.jinja:ro' "$SERVE"
 }