frank-large: raise ctx to 262144 to close the harness 400-zone

The harness clamps max_tokens to min(45056, contextWindow - est - 4096),
its chars/4 est under-counts the rendered prompt by ~3 % (measured:
152,938 -> 157,388 and 158,906 -> 165,301), and compaction fires only at
85 % -- so with window == engine ceiling 200192, every request in the
est ~146k-184k zone was a guaranteed 400. HALOGEN_CTX=262144 (native) +
KV pool 524288; harness window 217088 = ceiling - 45k absorbs the
estimate error (worst-case request ~219k <= 262144). models.yml updated
out-of-repo: contextWindow 217088, maxTokens 45056.

scripts/frank-large.env

@@ -22,15 +22,25 @@
 # tool calls verified, and the native 262,144 context.
 #
 # SHAPE — the knobs that are NOT free, with the arithmetic:
-#   HALOGEN_CTX=200192 is the PER-SLOT window and the per-conversation hard
+#   HALOGEN_CTX=262144 is the PER-SLOT window and the per-conversation hard
 #   ceiling — a prompt over it is a 400 naming the limit, never a silent
-#   truncation. Harness compaction fires at 70% = 140,134, and 140,134 +
-#   57,344 (harness maxTokens) = 197,478 <= 200,192 keeps prompt + budget
-#   inside the slot. models.yml contextWindow must quote 200192 or the
-#   harness discovers the wall as a 400.
-#   HALOGEN_KV_POOL_POSITIONS=400384 = KV_SLOTS(2) x CTX — the explicit
+#   truncation. RAISED from 200192 on 2026-10-07: the harness clamps
+#   max_tokens to contextWindow − est − 4096, its chars/4 est UNDER-counts
+#   the rendered prompt by ~3 % on code/agent traffic, and compaction only
+#   fires at 85 % — so with window == engine ceiling, every request over
+#   ~146k est (65-85 % of the window) was a guaranteed 400. Measured
+#   2026-10-07: est 152,938, server 157,388, request 43,158 vs room 42,804
+#   — over by 354, margin 4,096 < the 4,450 under-count.
+#   Harness contract (models.yml): contextWindow 217088, maxTokens 45056.
+#   Compaction fires at 85 % = 184,524 est ≈ 190k measured (Frank's 180k
+#   target). Worst-case request: prompt + budget <= 217088 − 4096 + 3 %
+#   est-error ≈ 219k <= 262144 — the 45k gap between harness window and
+#   engine ceiling absorbs the estimate error with ~7x margin (robust to a
+#   10 % under-count). Compaction rides on frank-secondary: input ≈
+#   threshold − keepRecent(20k) ≈ 170k measured, inside its 200,704 slot.
+#   HALOGEN_KV_POOL_POSITIONS=524288 = KV_SLOTS(2) x CTX — the explicit
 #   form of the engine's default, so the seam test can pin the product.
-#   KV costs ~28 KiB/position (FLAGS.md) => 400,384 x 28 KiB = 10.7 GiB.
+#   KV costs ~28 KiB/position (FLAGS.md) => 524,288 x 28 KiB = 14.0 GiB.
 #   HALOGEN_KV_SLOTS=2 restores the w4b-era shape on this box: the MTP
 #   drafter is NOT slot-locked on this engine (batching and speculation
 #   coexist — DFlash-era slots>1 law does NOT carry over; the card's own
@@ -39,11 +49,11 @@
 #   Memory ledger against the box's 121.2 GiB unified (the n-gram table is
 #   mmap'd page cache beside the checkpoint, not a pinned charge — the
 #   card's own quickstart arithmetic does not bill it):
-#     weights ~62 GiB resident + KV 10.7 + arena (HALOGEN_MAX_TOK=8192 =>
+#     weights ~62 GiB resident + KV 14.0 + arena (HALOGEN_MAX_TOK=8192 =>
 #     ~8 GiB per FLAGS.md arena formula 3.8+8.4*(MT/16384)) + vision ~2
-#     = ~82.7 GiB engine-side; HALOGEN_HOST_RESERVE_GIB=20 keeps the host
+#     = ~86 GiB engine-side; HALOGEN_HOST_RESERVE_GIB=20 keeps the host
 #     honest; baseline co-tenancy (frank-secondary, ComfyUI, Caddy/observ)
-#     ~10-15. ~18 GiB margin. The boot ledger is the referee — read it
+#     ~10-15. ~15 GiB margin. The boot ledger is the referee — read it
 #     after deploy and re-size if the engine prints a clamp.
 #   HALOGEN_SPEC_ADAPT=0 is MANDATORY (card): the default adaptive policy
 #   turns the MTP head off for whole requests after low acceptance and
@@ -57,8 +67,8 @@
 #     an absent temperature is no longer greedy. models.yml extraBody
 #     carries the same values — consistent, not load-bearing.
 #   * HALOGEN_MAX_TOK=8192 is only the DEFAULT for requests that omit
-#     max_tokens; the harness always sends 57344. Requests over
-#     HALOGEN_MAX_TOKENS_CAP (65536) are a 400 naming the cap. Cap and
+#     max_tokens; the harness sends at most its maxTokens 45056. Requests
+#     over HALOGEN_MAX_TOKENS_CAP (65536) are a 400 naming the cap. Cap and
 #     queue timeout are COUPLED (FLAGS.md table): 65536 at ~10 t/s serial
 #     worst case needs > 6550 s; 7200 honors it. Do not move one alone.
 #   * max_tokens INCLUDES thinking; a reasoning reply over a small budget
@@ -121,8 +131,8 @@ FRANK_LARGE_TOKENIZER_FILES="tokenizer.json chat_template.jinja tokenizer_config
 # --- engine flags (docs/FLAGS.md of the flash-server repo; anything unset
 # stays at the image default, which is what was qualified) ------------------
 HALOGEN_MODEL_ID=frank-large
-HALOGEN_CTX=200192
-HALOGEN_KV_POOL_POSITIONS=400384
+HALOGEN_CTX=262144
+HALOGEN_KV_POOL_POSITIONS=524288
 HALOGEN_KV_SLOTS=2
 HALOGEN_HOST_RESERVE_GIB=20
 # Spec decode: MTP head is INSIDE the checkpoint (do NOT set HALOGEN_MTP_HEAD);