From aa8cb0850564e28baf62f3f8cc02c69027dea118 Mon Sep 17 00:00:00 2001
From: difan <di.fan.cpa@gmail.com>
Date: Sun, 19 Jul 2026 18:32:40 -0400
Subject: [PATCH 1/2] feat(resistance-v2): age-banded supply histogram (lever
 f, default-off)

Replace the age-blind 130-week Res_hist histogram with a 20-price-bucket
x 4-age-band histogram (0-26w / 26-78w / 78-130w / 130-520w), 80 band-major
Res_hist columns. Age decay is applied at SCORE time via four
Resistance_supply.config band-weight fields (Overlay_validator axes), not
baked in at build time. Default weights [1;1;1;0] reproduce the pre-lever-f
age-blind 130w histogram bit-identically. The warehouse reader detects v3
(20-col) vs v4 (80-col) width and packs v3 into the youngest band, so existing
v3 warehouses keep scoring identically with no rebuild. Warehouse v4 rebuild
deferred pending the bundle verdict.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 dev/status/resistance-v2.md                   |  12 ++
 .../resistance/lib/resistance_supply.ml       |  78 ++++++++--
 .../resistance/lib/resistance_supply.mli      |  65 ++++++--
 .../resistance/test/test_resistance_supply.ml | 143 +++++++++++++++++-
 .../lib/resistance_sketch.ml                  |  48 ++++--
 .../lib/resistance_sketch.mli                 |  26 ++--
 .../test/test_resistance_sketch.ml            |  42 ++++-
 .../test/test_stock_analysis.ml               |   8 +-
 .../snapshot/lib/snapshot_schema.ml           |   4 +-
 .../snapshot/lib/snapshot_schema.mli          |  49 ++++--
 .../data_panel/snapshot/test/test_snapshot.ml |   4 +-
 .../snapshot/test/test_snapshot_schema.ml     |  18 ++-
 .../gen/lib/live_resistance_sketch.ml         |  16 +-
 .../gen/test/test_live_resistance_sketch.ml   |   5 +-
 .../strategy/lib/resistance_sketch_reader.ml  |  35 ++++-
 .../strategy/lib/resistance_sketch_reader.mli |  20 ++-
 .../test/test_resistance_sketch_reader.ml     |  79 ++++++++--
 17 files changed, 552 insertions(+), 100 deletions(-)

diff --git a/dev/status/resistance-v2.md b/dev/status/resistance-v2.md
index cabf62330..15ff7a3d2 100644
--- a/dev/status/resistance-v2.md
+++ b/dev/status/resistance-v2.md
@@ -198,6 +198,18 @@ load-bearing; binary grade → searchable weight; kill the 5h armed-run wall).
    bump + one full warehouse rebuild. Gate to build: lever (c)'s floor
    surface first; build (f) only if the floor verdict shows the mechanism
    wants real age structure (e.g. optimal floors regime-unstable).
+   **CODE LANDED 2026-07-19 (PR `feat/resistance-v2-age-bands`, default-off):**
+   schema `Res_hist` is now 80 band-major cells (4 age bands × 20 price
+   buckets, `Snapshot_schema.n_age_bands`/`n_hist_cells`); the pipeline
+   accumulates the 520-week histogram into age bands; `Resistance_supply`
+   collapses bands via four `config.band_weight_*` fields
+   (`[@sexp.default 1/1/1/0]`, Overlay_validator axes) at score time — default
+   weights `[1;1;1;0]` reproduce the pre-lever-f age-blind 130w histogram
+   bit-identically (pinned by `test_default_collapse_sums_recent_bands`). The
+   warehouse reader detects v3 (20-column) vs v4 (80-column) width and packs
+   v3 into the youngest band, so **existing v3 warehouses keep scoring
+   identically with NO rebuild** (`hist_bands_of_legacy`). The v4 warehouse
+   rebuild is DEFERRED pending the bundle verdict — no rebuild in this PR.
 4. dedup-v2 warehouse deletable (v3 certified bit-identical:
    `scenarios-2026-07-16-131756` baseline = Run D to 13 decimals).
 
diff --git a/trading/analysis/weinstein/resistance/lib/resistance_supply.ml b/trading/analysis/weinstein/resistance/lib/resistance_supply.ml
index 93db065ec..95f3af36c 100644
--- a/trading/analysis/weinstein/resistance/lib/resistance_supply.ml
+++ b/trading/analysis/weinstein/resistance/lib/resistance_supply.ml
@@ -1,12 +1,19 @@
 open Core
 open Weinstein_types
 
+(* Age bands (lever f), youngest first, locked to [Snapshot_schema] band
+   boundaries [0-26w / 26-78w / 78-130w / 130-520w]. Bands 0..[_n_recent_bands-1]
+   union to the pre-lever-f trailing-130w histogram window; band 3 is the
+   130-520w extension, weighted 0 by default so scoring is unchanged. *)
+let n_age_bands = 4
+let _n_recent_bands = 3
+
 type sketch = {
   max_high_130w : float;
   max_high_260w : float;
   max_high_520w : float;
   bars_seen : float;
-  hist : float array;
+  hist_bands : float array array;
   anchor_close : float;
 }
 
@@ -20,6 +27,10 @@ type config = {
   insufficient_score : float;
   heavy_resistance_bars : int;
   moderate_resistance_bars : int;
+  band_weight_0_26w : float; [@sexp.default 1.0]
+  band_weight_26_78w : float; [@sexp.default 1.0]
+  band_weight_78_130w : float; [@sexp.default 1.0]
+  band_weight_130_520w : float; [@sexp.default 0.0]
 }
 [@@deriving sexp]
 
@@ -35,8 +46,49 @@ let default_config =
     insufficient_score = 0.5;
     heavy_resistance_bars = 8;
     moderate_resistance_bars = 3;
+    (* No-op defaults (experiment-flag-discipline R1): the three 0-130w bands
+       weighted 1.0 and the 130-520w band 0.0 collapses the age-banded histogram
+       back to the pre-lever-f age-blind 130w histogram, bit-identically. *)
+    band_weight_0_26w = 1.0;
+    band_weight_26_78w = 1.0;
+    band_weight_78_130w = 1.0;
+    band_weight_130_520w = 0.0;
   }
 
+let _band_weights (config : config) =
+  [|
+    config.band_weight_0_26w;
+    config.band_weight_26_78w;
+    config.band_weight_78_130w;
+    config.band_weight_130_520w;
+  |]
+
+(* Pack a legacy age-blind histogram (the v3 warehouse / pre-lever-f shape) into
+   the age-banded layout: all mass in the youngest band, the rest zero. With
+   [default_config] band weights ([1;1;1;0]) the collapsed effective histogram
+   equals [flat] exactly, so a v3 warehouse scores bit-identically. *)
+let hist_bands_of_legacy flat =
+  let n = Array.length flat in
+  Array.init n_age_bands ~f:(fun b ->
+      if b = 0 then Array.copy flat else Array.create ~len:n 0.0)
+
+(* Collapse the age-banded histogram into one effective per-bucket vector by
+   applying the per-band config weights: [effective.(k) = Σ_b w_b * bands_b.(k)].
+   Non-finite cells count as 0 (same guard the per-bucket scorer applies). *)
+let _effective_hist ~(config : config) ~hist_bands =
+  let weights = _band_weights config in
+  let n_buckets =
+    Array.fold hist_bands ~init:0 ~f:(fun acc band ->
+        Int.max acc (Array.length band))
+  in
+  let eff = Array.create ~len:n_buckets 0.0 in
+  Array.iteri hist_bands ~f:(fun b band ->
+      let w = if b < Array.length weights then weights.(b) else 0.0 in
+      Array.iteri band ~f:(fun k c ->
+          let c = if Float.is_finite c then c else 0.0 in
+          eff.(k) <- eff.(k) +. (w *. c)));
+  eff
+
 type result = {
   score : float;
   recent_weighted_bars : float;
@@ -110,11 +162,12 @@ let _insufficient ~(config : config) =
   }
 
 let _scored ~(config : config) ~(sketch : sketch) ~breakout_price =
+  let effective = _effective_hist ~config ~hist_bands:sketch.hist_bands in
   let k_min =
-    _first_bucket ~n_buckets:(Array.length sketch.hist)
+    _first_bucket ~n_buckets:(Array.length effective)
       ~anchor:sketch.anchor_close ~breakout:breakout_price
   in
-  let weighted, max_bucket = _recent_supply ~config ~hist:sketch.hist ~k_min in
+  let weighted, max_bucket = _recent_supply ~config ~hist:effective ~k_min in
   let quality = _quality_of ~config ~sketch ~breakout_price ~max_bucket in
   let score =
     (* When the histogram holds mass at/above the breakout it speaks for
@@ -145,12 +198,19 @@ let is_virgin ~(sketch : sketch) ~breakout_price =
   && Float.is_finite breakout_price
   && Float.(breakout_price >= sketch.max_high_520w)
 
-(* Closing-basis "new high ground": no weekly bar in the trailing histogram
-   window sits at/above the current close (every [hist] bin is 0). Robust to
-   the own-week-high artifact that makes [is_virgin] unsatisfiable on a
-   close-anchored breakout price (see .mli — AXTI 2026-01-06). A non-finite bin
-   fails the [= 0.0] test, so no explicit finiteness check on [hist] is needed. *)
+(* Closing-basis "new high ground": no weekly bar in the trailing 130-week
+   histogram window (age bands 0..[_n_recent_bands-1], which union to that
+   window) sits at/above the current close — every recent-band bin is 0. The
+   130-520w band is ignored, keeping this predicate bit-identical to its
+   pre-lever-f 130w semantics (and to a v3 warehouse whose mass all lands in
+   band 0). Weight-independent by design — a structural emptiness test, not a
+   scoring measure. Robust to the own-week-high artifact that makes [is_virgin]
+   unsatisfiable on a close-anchored breakout price (see .mli — AXTI
+   2026-01-06). A non-finite bin fails the [= 0.0] test, so no explicit
+   finiteness check on the bins is needed. *)
 let is_clear_of_supply ~(sketch : sketch) =
   _sketch_is_finite sketch
   && Float.(sketch.bars_seen > 0.0)
-  && Array.for_all sketch.hist ~f:(fun count -> Float.(count = 0.0))
+  && Array.for_alli sketch.hist_bands ~f:(fun b band ->
+      b >= _n_recent_bands
+      || Array.for_all band ~f:(fun count -> Float.(count = 0.0)))
diff --git a/trading/analysis/weinstein/resistance/lib/resistance_supply.mli b/trading/analysis/weinstein/resistance/lib/resistance_supply.mli
index ff262baa5..9871a3565 100644
--- a/trading/analysis/weinstein/resistance/lib/resistance_supply.mli
+++ b/trading/analysis/weinstein/resistance/lib/resistance_supply.mli
@@ -18,16 +18,34 @@ type sketch = {
   max_high_260w : float;  (** Same, 260 weekly bars. *)
   max_high_520w : float;  (** Same, 520 weekly bars. *)
   bars_seen : float;  (** True weekly-bar count available (capped 520). *)
-  hist : float array;
-      (** Trailing-130w histogram: [hist.(k)] counts weekly bars whose
-          mid-price lies in [anchor * 2^(k/n), anchor * 2^((k+1)/n)) where
-          [n = Array.length hist] buckets span one doubling. *)
+  hist_bands : float array array;
+      (** Age-banded histogram (lever f): [hist_bands.(b).(k)] counts weekly
+          bars of age band [b] (0..{!n_age_bands}-1, youngest first —
+          [0-26w / 26-78w / 78-130w / 130-520w]) whose mid-price lies in
+          [anchor * 2^(k/n), anchor * 2^((k+1)/n)) where [n] is the per-band
+          bucket count. {!analyze} collapses the bands into one effective
+          histogram via the [config] band weights at score time. A v3 warehouse
+          / age-blind histogram maps to the youngest band with the rest zero —
+          see {!hist_bands_of_legacy}. *)
   anchor_close : float;
       (** The raw close the histogram was anchored at (the sketch row's own
           close). *)
 }
 (** One symbol-day's sketch cells, as stored in the warehouse columns. *)
 
+val n_age_bands : int
+(** [n_age_bands] is the number of {!sketch.hist_bands} age bands (4). Locked to
+    [Snapshot_schema.n_age_bands] (the pure scoring layer cannot depend on the
+    snapshot layer, so the two are pinned equal by test). *)
+
+val hist_bands_of_legacy : float array -> float array array
+(** [hist_bands_of_legacy flat] packs a legacy age-blind histogram (the v3
+    warehouse / pre-lever-f 130-week shape) into the {!n_age_bands}-band layout:
+    all mass in the youngest band, the remaining bands zero. Under
+    {!default_config} band weights ([1;1;1;0]) the effective histogram
+    {!analyze} collapses equals [flat] bit-for-bit, so a v3 warehouse scores
+    identically to before lever f. *)
+
 type config = {
   proximity_decay : float;
       (** Multiplicative weight decay per bucket above the breakout: supply [j]
@@ -54,6 +72,21 @@ type config = {
       (** Grade derivation: max single-bucket count at/above the breakout that
           classifies as [Heavy_resistance] (mirrors v1). *)
   moderate_resistance_bars : int;  (** Same for [Moderate_resistance]. *)
+  band_weight_0_26w : float; [@sexp.default 1.0]
+      (** Lever f: score-time weight for the 0-26w age band. Defaults to 1.0
+          (the pre-lever-f no-op). *)
+  band_weight_26_78w : float; [@sexp.default 1.0]
+      (** Score-time weight for the 26-78w age band. Default 1.0. *)
+  band_weight_78_130w : float; [@sexp.default 1.0]
+      (** Score-time weight for the 78-130w age band. Default 1.0. *)
+  band_weight_130_520w : float; [@sexp.default 0.0]
+      (** Score-time weight for the 130-520w age band. Defaults to 0.0 so the
+          band is inert; the three 0-130w bands at weight 1.0 reproduce the
+          pre-lever-f age-blind 130w histogram exactly. Each band weight is an
+          [Overlay_validator] axis (a real [config] sub-field), so the age decay
+          is searchable without a warehouse rebuild (experiment-flag-discipline
+          R1/R2). The four fields carry [@sexp.default]s so a config sexp
+          written before lever f (without them) still round-trips. *)
 }
 [@@deriving sexp]
 (** [@@deriving sexp] so this config can be nested (as an [option]) inside
@@ -64,7 +97,8 @@ type config = {
 val default_config : config
 (** No-op-adjacent defaults: decay 0.7, saturation 8 bars, floors 0.4 / 0.25 /
     0.1, [min_history_bars = 0], insufficient score 0.5, grade thresholds 8 / 3
-    (v1 parity). All searchable; none hardcoded at use sites. *)
+    (v1 parity), age-band weights 1 / 1 / 1 / 0 (collapses to the pre-lever-f
+    age-blind 130w histogram). All searchable; none hardcoded at use sites. *)
 
 type result = {
   score : float;
@@ -85,9 +119,12 @@ val analyze : config:config -> sketch:sketch -> breakout_price:float -> result
 (** [analyze ~config ~sketch ~breakout_price] scores the overhead supply a
     breakout at [breakout_price] faces.
 
-    Score composition (plan §D5):
-    - recent component: proximity-weighted histogram mass at/above the breakout,
-      saturated at [saturation_bars];
+    Score composition (plan §D5). The age bands are first collapsed into one
+    effective per-bucket histogram by the [config] band weights
+    ([effective.(k) = Σ_b w_b * hist_bands.(b).(k)]); the rest scores that
+    effective histogram exactly as before lever f:
+    - recent component: proximity-weighted effective-histogram mass at/above the
+      breakout, saturated at [saturation_bars];
     - horizon floors: ONLY when the histogram holds no mass at/above the
       breakout but a max-high proves overhead exists, the score falls back to
       [recent_far_floor] / [stale_mid_floor] / [stale_old_floor] by the age of
@@ -126,10 +163,14 @@ val is_virgin : sketch:sketch -> breakout_price:float -> bool
 
 val is_clear_of_supply : sketch:sketch -> bool
 (** [is_clear_of_supply ~sketch] is [true] iff the sketch is finite,
-    [bars_seen > 0], and EVERY [hist] bin is [0] — i.e. zero measured overhead
-    mass: no prior (finalized) weekly bar in the trailing 130-week histogram
-    window has a high above the current close whose mid-price
-    ([(high + low) / 2]) falls at or above it. The histogram producer gates on
+    [bars_seen > 0], and EVERY bin of the {b 0-130w age bands} (bands [0..2],
+    which union to the trailing-130w window) is [0] — i.e. zero measured
+    overhead mass: no prior (finalized) weekly bar in the trailing 130-week
+    histogram window has a high above the current close whose mid-price
+    ([(high + low) / 2]) falls at or above it. The 130-520w band is ignored so
+    this predicate keeps its exact pre-lever-f 130w semantics (and a v3
+    warehouse, whose mass all lands in band 0, gives the same answer);
+    weight-independent by design. The histogram producer gates on
     [weekly_high > anchor] and buckets by the mid-price (see
     [Snapshot_pipeline.Resistance_sketch] and its .mli — the source of truth).
     This is exactly the recent-overhead mass {!analyze} scores as its histogram
diff --git a/trading/analysis/weinstein/resistance/test/test_resistance_supply.ml b/trading/analysis/weinstein/resistance/test/test_resistance_supply.ml
index d2800dc06..048d9f595 100644
--- a/trading/analysis/weinstein/resistance/test/test_resistance_supply.ml
+++ b/trading/analysis/weinstein/resistance/test/test_resistance_supply.ml
@@ -6,6 +6,13 @@ module Resistance_sketch = Snapshot_pipeline.Resistance_sketch
 
 let _config = Resistance_supply.default_config
 let _n_buckets = 20
+let _n_bands = Resistance_supply.n_age_bands
+
+(* A single 20-bucket price histogram with [counts] placed. *)
+let _band counts =
+  let a = Array.create ~len:_n_buckets 0.0 in
+  List.iter counts ~f:(fun (k, c) -> a.(k) <- c);
+  a
 
 (* A sketch with no overhead anywhere: every max-high below the breakout. *)
 let _virgin_sketch =
@@ -14,19 +21,28 @@ let _virgin_sketch =
     max_high_260w = 95.0;
     max_high_520w = 99.0;
     bars_seen = 520.0;
-    hist = Array.create ~len:_n_buckets 0.0;
+    hist_bands = Resistance_supply.hist_bands_of_legacy (_band []);
     anchor_close = 100.0;
   }
 
+(* Legacy age-blind histogram (all mass in the youngest band) at [max_high]. *)
 let _with_hist ?(max_high = 150.0) counts =
-  let hist = Array.create ~len:_n_buckets 0.0 in
-  List.iter counts ~f:(fun (k, c) -> hist.(k) <- c);
   {
     _virgin_sketch with
     max_high_130w = max_high;
     max_high_260w = max_high;
     max_high_520w = max_high;
-    hist;
+    hist_bands = Resistance_supply.hist_bands_of_legacy (_band counts);
+  }
+
+(* A sketch with an explicit 4-band histogram (each element a 20-bucket band). *)
+let _with_bands ?(max_high = 150.0) bands =
+  {
+    _virgin_sketch with
+    max_high_130w = max_high;
+    max_high_260w = max_high;
+    max_high_520w = max_high;
+    hist_bands = bands;
   }
 
 let test_virgin_scores_zero _ =
@@ -216,6 +232,7 @@ let _v2_quality bars ~breakout_price =
   let weekly_prefix = Weekly_prefix.build bars_arr in
   let sketch = Resistance_sketch.compute ~weekly_prefix ~bars_arr in
   let i = Array.length bars_arr - 1 in
+  let n_buckets = Array.length sketch.hist / _n_bands in
   let result =
     Resistance_supply.analyze ~config:_config
       ~sketch:
@@ -224,7 +241,10 @@ let _v2_quality bars ~breakout_price =
           max_high_260w = sketch.max_high_260w.(i);
           max_high_520w = sketch.max_high_520w.(i);
           bars_seen = sketch.bars_seen.(i);
-          hist = Array.map sketch.hist ~f:(fun row -> row.(i));
+          hist_bands =
+            Array.init _n_bands ~f:(fun b ->
+                Array.init n_buckets ~f:(fun bucket ->
+                    sketch.hist.((b * n_buckets) + bucket).(i)));
           anchor_close = bars_arr.(i).Types.Daily_price.close_price;
         }
       ~breakout_price
@@ -328,6 +348,112 @@ let test_own_week_high_divergence _ =
       Resistance_supply.is_clear_of_supply ~sketch:axti_shape )
     (equal_to (false, true))
 
+(* ------------------------------------------------------------------ *)
+(* Age-banded histogram (lever f): default bit-identical + the lever.  *)
+(* ------------------------------------------------------------------ *)
+
+(* Default parity: at default weights ([1;1;1;0]) the effective histogram is the
+   SUM of the three 0-130w bands. 3 bars in bucket 0 split one-per-recent-band
+   score identically to the same 3 bars packed into the youngest band (the v3
+   layout) — both the moderate 3/8 score. This is the "v3-shaped sketch scores
+   identically" parity: summing bands 0-2 = the pre-lever-f age-blind hist. *)
+let test_default_collapse_sums_recent_bands _ =
+  let split =
+    [| _band [ (0, 1.0) ]; _band [ (0, 1.0) ]; _band [ (0, 1.0) ]; _band [] |]
+  in
+  let legacy = Resistance_supply.hist_bands_of_legacy (_band [ (0, 3.0) ]) in
+  let r_split =
+    Resistance_supply.analyze ~config:_config ~sketch:(_with_bands split)
+      ~breakout_price:100.0
+  in
+  let r_legacy =
+    Resistance_supply.analyze ~config:_config ~sketch:(_with_bands legacy)
+      ~breakout_price:100.0
+  in
+  assert_that (r_split, r_legacy)
+    (all_of
+       [
+         field
+           (fun ((s : Resistance_supply.result), _) -> s.score)
+           (float_equal 0.375);
+         field
+           (fun (_, (l : Resistance_supply.result)) -> l.score)
+           (float_equal 0.375);
+         field
+           (fun ((s : Resistance_supply.result), _) -> s.quality)
+           (equal_to Weinstein_types.Moderate_resistance);
+       ])
+
+(* Default inert 130-520w band: 8 bars living ONLY in the stale band contribute
+   nothing to the effective histogram (weight 0), so the score falls to the
+   horizon floor proven by the max-highs, not the saturated 1.0. *)
+let test_stale_band_inert_at_default _ =
+  let bands = [| _band []; _band []; _band []; _band [ (0, 8.0) ] |] in
+  let result =
+    Resistance_supply.analyze ~config:_config ~sketch:(_with_bands bands)
+      ~breakout_price:100.0
+  in
+  assert_that result
+    (all_of
+       [
+         field
+           (fun (r : Resistance_supply.result) -> r.recent_weighted_bars)
+           (float_equal 0.0);
+         field
+           (fun (r : Resistance_supply.result) -> r.score)
+           (float_equal _config.recent_far_floor);
+       ])
+
+(* The lever works: arming the 130-520w band weight makes its 8 bars saturate
+   the score to 1.0 (Heavy), proving the age decay is a real score-time knob. *)
+let test_stale_band_weight_activates _ =
+  let bands = [| _band []; _band []; _band []; _band [ (0, 8.0) ] |] in
+  let config = { _config with band_weight_130_520w = 1.0 } in
+  let result =
+    Resistance_supply.analyze ~config ~sketch:(_with_bands bands)
+      ~breakout_price:100.0
+  in
+  assert_that result
+    (all_of
+       [
+         field (fun (r : Resistance_supply.result) -> r.score) (float_equal 1.0);
+         field
+           (fun (r : Resistance_supply.result) -> r.quality)
+           (equal_to Weinstein_types.Heavy_resistance);
+       ])
+
+(* R1/R2 sexp back-compat: a config sexp written before lever f (lacking the
+   four band-weight fields) still parses, the [@sexp.default]s filling in the
+   no-op weights (1 / 1 / 1 / 0). *)
+let test_config_parses_without_band_weights _ =
+  let stripped =
+    match Resistance_supply.sexp_of_config _config with
+    | Sexp.List fields ->
+        Sexp.List
+          (List.filter fields ~f:(function
+            | Sexp.List (Sexp.Atom k :: _) ->
+                not (String.is_prefix k ~prefix:"band_weight")
+            | _ -> true))
+    | other -> other
+  in
+  let parsed = Resistance_supply.config_of_sexp stripped in
+  assert_that
+    (parsed.band_weight_0_26w, parsed.band_weight_130_520w)
+    (all_of
+       [
+         field (fun (a, _) -> a) (float_equal 1.0);
+         field (fun (_, b) -> b) (float_equal 0.0);
+       ])
+
+(* [is_clear_of_supply] ignores the 130-520w band: mass there alone is still
+   "clear" (recent overhead empty), keeping the virgin-readmission lever's 130w
+   semantics unchanged. *)
+let test_is_clear_ignores_stale_band _ =
+  let bands = [| _band []; _band []; _band []; _band [ (0, 8.0) ] |] in
+  assert_that
+    (Resistance_supply.is_clear_of_supply ~sketch:(_with_bands bands))
+    (equal_to true)
+
 let suite =
   "Resistance_supply tests"
   >::: [
@@ -347,6 +473,13 @@ let suite =
          "is_virgin agrees with analyze" >:: test_is_virgin_agrees_with_analyze;
          "is_clear_of_supply" >:: test_is_clear_of_supply;
          "own-week-high divergence" >:: test_own_week_high_divergence;
+         "default collapse sums recent bands"
+         >:: test_default_collapse_sums_recent_bands;
+         "stale band inert at default" >:: test_stale_band_inert_at_default;
+         "stale band weight activates" >:: test_stale_band_weight_activates;
+         "config parses without band weights"
+         >:: test_config_parses_without_band_weights;
+         "is_clear ignores stale band" >:: test_is_clear_ignores_stale_band;
        ]
 
 let () = run_test_tt_main suite
diff --git a/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.ml b/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.ml
index 974a7f6f1..fd4b6b15f 100644
--- a/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.ml
+++ b/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.ml
@@ -15,10 +15,31 @@ type t = {
 let _horizon_130_weeks = 130
 let _horizon_260_weeks = 260
 let _horizon_520_weeks = 520
-let _hist_lookback_weeks = 130
+
+(* Age-banded histogram (lever f): the histogram now looks back the full 520
+   weekly bars, split into four age bands by a weekly bar's age relative to the
+   row (the partial current week is age 0, the most recent finalized week age 1,
+   ...). Band boundaries are half-open: [0,26) / [26,78) / [78,130) / [130,520).
+   The three 0-130w bands union to the pre-lever-f trailing-130w window, so
+   summing them reproduces the old age-blind histogram exactly. *)
+let _hist_lookback_weeks = 520
+let _age_break_26_weeks = 26
+let _age_break_78_weeks = 78
+let _age_break_130_weeks = 130
 let _bars_seen_cap = 520
 let _ln2 = Float.log 2.0
 
+(* Age band index (0..n_age_bands-1) for a weekly bar of [age] weeks. *)
+let _age_band_of ~age =
+  if age < _age_break_26_weeks then 0
+  else if age < _age_break_78_weeks then 1
+  else if age < _age_break_130_weeks then 2
+  else 3
+
+(* Column index of price bucket [bucket] within age band [band] in the
+   band-major [Res_hist] layout (matches [Snapshot_schema] cell ordering). *)
+let _cell_index ~band ~bucket = (band * Snapshot_schema.n_hist_buckets) + bucket
+
 (* Pop deque entries whose high is <= the incoming one, then push [j].
    Keeps [dq] a decreasing-highs monotonic deque of finalized indices. *)
 let _push_monotonic dq (highs : float array) j =
@@ -71,15 +92,17 @@ let _bucket_of ~anchor ~mid =
   in
   if Float.is_finite k then Some (Int.of_float k) else None
 
-(* Count one weekly bar into [hist] at day [i] when it sits above [anchor]
-   and its mid lands in a canonical bucket. Mirrors the v1 mapper's
-   accumulation rule: [high > breakout] gates, the mid-price buckets. *)
-let _accumulate_hist ~hist ~i ~anchor ~weekly_high ~weekly_low =
+(* Count one weekly bar of age [band] into [hist] at day [i] when it sits above
+   [anchor] and its mid lands in a canonical bucket. Mirrors the v1 mapper's
+   accumulation rule: [high > breakout] gates, the mid-price buckets; the age
+   band selects which of the four band-major column groups the count lands in. *)
+let _accumulate_hist ~hist ~i ~band ~anchor ~weekly_high ~weekly_low =
   if Float.(weekly_high > anchor) then
     let mid = (weekly_high +. weekly_low) /. 2.0 in
     match _bucket_of ~anchor ~mid with
-    | Some k when k >= 0 && k < Snapshot_schema.n_hist_buckets ->
-        hist.(k).(i) <- hist.(k).(i) +. 1.0
+    | Some bucket when bucket >= 0 && bucket < Snapshot_schema.n_hist_buckets ->
+        let cell = _cell_index ~band ~bucket in
+        hist.(cell).(i) <- hist.(cell).(i) +. 1.0
     | _ -> ()
 
 let _hist_for_day ~hist ~(weekly_prefix : Weekly_prefix.t) ~i ~anchor =
@@ -87,12 +110,16 @@ let _hist_for_day ~hist ~(weekly_prefix : Weekly_prefix.t) ~i ~anchor =
   let fc = weekly_prefix.finalized_count_at_day.(i) in
   let m_fin = Int.min (_hist_lookback_weeks - 1) fc in
   for j = fc - m_fin to fc - 1 do
-    _accumulate_hist ~hist ~i ~anchor
+    (* Finalized week [j] is [fc - j] weeks before the current partial week. *)
+    let band = _age_band_of ~age:(fc - j) in
+    _accumulate_hist ~hist ~i ~band ~anchor
       ~weekly_high:fin.(j).Types.Daily_price.high_price
       ~weekly_low:fin.(j).Types.Daily_price.low_price
   done;
+  (* The partial (current) week is age 0 -> youngest band. *)
   let p = weekly_prefix.partial_per_day.(i) in
-  _accumulate_hist ~hist ~i ~anchor ~weekly_high:p.Types.Daily_price.high_price
+  _accumulate_hist ~hist ~i ~band:0 ~anchor
+    ~weekly_high:p.Types.Daily_price.high_price
     ~weekly_low:p.Types.Daily_price.low_price
 
 (* Corrupt-anchor day: every sketch cell for day [i] degrades to NaN. *)
@@ -119,8 +146,7 @@ let _bars_seen_column ~fc_at_day =
       Float.of_int (Int.min (fc + 1) _bars_seen_cap))
 
 let _empty_hist ~n =
-  Array.init Snapshot_schema.n_hist_buckets ~f:(fun _ ->
-      Array.create ~len:n 0.0)
+  Array.init Snapshot_schema.n_hist_cells ~f:(fun _ -> Array.create ~len:n 0.0)
 
 let compute ~(weekly_prefix : Weekly_prefix.t)
     ~(bars_arr : Types.Daily_price.t array) =
diff --git a/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.mli b/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.mli
index fd5ada218..2724f9030 100644
--- a/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.mli
+++ b/trading/analysis/weinstein/snapshot_pipeline/lib/resistance_sketch.mli
@@ -20,12 +20,19 @@
       130/260/520 weekly bars ending at day [i] (partial week included).
     - [bars_seen].(i): true weekly-bar count available at day [i], capped at
       520 — the honest [Insufficient_history] input.
-    - [hist].(k).(i): count of weekly bars among the trailing 130 whose
-      mid-price [(high + low) / 2] lies in the log band
-      [C * 2^(k/20), C * 2^((k+1)/20)) above the day's raw close [C], and
-      whose high exceeds [C]. Buckets past
-      [Snapshot_schema.n_hist_buckets - 1] (supply more than 2x above [C])
-      are dropped.
+    - [hist].(cell).(i): {b age-banded} count at daily index [i]. The
+      [Snapshot_schema.n_hist_cells] rows are band-major: cell
+      [band * n_hist_buckets + bucket] holds age band [band] and price bucket
+      [bucket]. The four age bands cover a weekly bar's age relative to day [i]
+      (age 0 = the partial current week, age 1 = the most recent finalized
+      week, ...): [0-26w / 26-78w / 78-130w / 130-520w] (half-open). Within a
+      band, [bucket] counts weekly bars whose mid-price [(high + low) / 2] lies
+      in the log band [C * 2^(bucket/20), C * 2^((bucket+1)/20)) above the day's
+      raw close [C] and whose high exceeds [C]. Bucket indices past
+      [Snapshot_schema.n_hist_buckets - 1] (supply more than 2x above [C]) are
+      dropped. Summing the three 0-130w bands reproduces the pre-lever-f
+      age-blind trailing-130w histogram exactly; the 130-520w band measures
+      older supply the horizon max-highs previously only floored.
 
     Corrupt-bar guard: when day [i]'s raw close is non-positive or
     non-finite, every sketch cell at [i] is [Float.nan].
@@ -41,9 +48,10 @@ type t = {
   max_high_520w : float array;
   bars_seen : float array;
   hist : float array array;
-      (** [hist.(k).(i)] = bucket [k]'s count at daily index [i]; the first
-          dimension has {!Data_panel_snapshot.Snapshot_schema.n_hist_buckets}
-          rows. *)
+      (** [hist.(cell).(i)] = band-major cell [cell]'s count at daily index [i];
+          the first dimension has
+          {!Data_panel_snapshot.Snapshot_schema.n_hist_cells} rows (cell
+          [band * n_hist_buckets + bucket]). *)
 }
 (** Per-day sketch arrays, each aligned to the daily bar array (index [i] = day
     [i]). *)
diff --git a/trading/analysis/weinstein/snapshot_pipeline/test/test_resistance_sketch.ml b/trading/analysis/weinstein/snapshot_pipeline/test/test_resistance_sketch.ml
index 045631bcc..22e7fd3d5 100644
--- a/trading/analysis/weinstein/snapshot_pipeline/test/test_resistance_sketch.ml
+++ b/trading/analysis/weinstein/snapshot_pipeline/test/test_resistance_sketch.ml
@@ -170,9 +170,15 @@ let test_histogram_buckets _ =
   in
   let sketch, _, _ = _compute bars in
   let last = (5 * 5) - 1 in
+  (* All five weeks are age < 130 at the final day, so per-bucket the SUM over
+     age bands reproduces the pre-lever-f age-blind histogram. *)
   let counts =
-    List.init Snapshot_schema.n_hist_buckets ~f:(fun k ->
-        sketch.hist.(k).(last))
+    List.init Snapshot_schema.n_hist_buckets ~f:(fun bucket ->
+        List.sum
+          (module Float)
+          (List.init Snapshot_schema.n_age_bands ~f:Fn.id)
+          ~f:(fun band ->
+            sketch.hist.((band * Snapshot_schema.n_hist_buckets) + bucket).(last)))
   in
   let expected =
     List.init Snapshot_schema.n_hist_buckets ~f:(fun k ->
@@ -180,6 +186,37 @@ let test_histogram_buckets _ =
   in
   assert_that counts (elements_are expected)
 
+(* Age banding (lever f): a resistance spike at week 0 of a 200-week series is
+   ~200 weeks old at the final day, so it lands in the 130-520w age band (band
+   3) — the histogram now MEASURES old supply the pre-lever-f 130w window
+   dropped. Non-spike weeks have high = close (5), so they are gated out
+   ([weekly_high > anchor] fails). Recent bands (0-2) are therefore empty and
+   band 3 holds exactly the one spike bar. *)
+let test_age_bands_separate_old_supply _ =
+  let week_shape w =
+    if w = 0 then Some (7.0, 6.0) (* mid 6.5 over anchor 5 -> bucket 7 *)
+    else Some (5.0, 4.0)
+    (* high = anchor -> not counted *)
+  in
+  let sketch, _, bars_arr = _compute (_weeks_bars ~n_weeks:200 ~week_shape) in
+  let last = Array.length bars_arr - 1 in
+  let n_buckets = Snapshot_schema.n_hist_buckets in
+  let band_total band =
+    List.sum
+      (module Float)
+      (List.init n_buckets ~f:Fn.id)
+      ~f:(fun bucket -> sketch.hist.((band * n_buckets) + bucket).(last))
+  in
+  let recent_total = List.sum (module Float) [ 0; 1; 2 ] ~f:band_total in
+  assert_that
+    (recent_total, band_total 3, sketch.hist.((3 * n_buckets) + 7).(last))
+    (all_of
+       [
+         field (fun (r, _, _) -> r) (float_equal 0.0);
+         field (fun (_, s, _) -> s) (float_equal 1.0);
+         field (fun (_, _, b) -> b) (float_equal 1.0);
+       ])
+
 let test_corrupt_close_degrades_to_nan _ =
   let bars =
     List.init 5 ~f:(fun d ->
@@ -412,6 +449,7 @@ let suite =
          >:: test_rolling_max_windows_and_eviction;
          "bars_seen counts weeks" >:: test_bars_seen_counts_weeks;
          "histogram buckets" >:: test_histogram_buckets;
+         "age bands separate old supply" >:: test_age_bands_separate_old_supply;
          "corrupt close degrades to NaN" >:: test_corrupt_close_degrades_to_nan;
          "virgin parity with v1 mapper" >:: test_virgin_parity_with_v1_mapper;
          "pipeline populates sketch columns"
diff --git a/trading/analysis/weinstein/stock_analysis/test/test_stock_analysis.ml b/trading/analysis/weinstein/stock_analysis/test/test_stock_analysis.ml
index 2bd2d1ee0..288f166bf 100644
--- a/trading/analysis/weinstein/stock_analysis/test/test_stock_analysis.ml
+++ b/trading/analysis/weinstein/stock_analysis/test/test_stock_analysis.ml
@@ -605,7 +605,8 @@ let make_sketch () : Resistance_supply.sketch =
     max_high_260w = 200.0;
     max_high_520w = 200.0;
     bars_seen = 200.0;
-    hist = Array.create ~len:20 0.0;
+    hist_bands =
+      Resistance_supply.hist_bands_of_legacy (Array.create ~len:20 0.0);
     anchor_close = 100.0;
   }
 
@@ -663,7 +664,10 @@ let virgin_sketch () : Resistance_supply.sketch =
 let overhead_sketch () : Resistance_supply.sketch =
   let hist = Array.create ~len:20 0.0 in
   hist.(0) <- 5.0;
-  { (make_sketch ()) with hist }
+  {
+    (make_sketch ()) with
+    hist_bands = Resistance_supply.hist_bands_of_legacy hist;
+  }
 
 (** Run [analyze_with_callbacks] over rising bars with [config] and a
     [get_sketch] closure returning [sketch_opt]; return [t.virgin_readmission].
diff --git a/trading/trading/data_panel/snapshot/lib/snapshot_schema.ml b/trading/trading/data_panel/snapshot/lib/snapshot_schema.ml
index 4906e41fa..adf558ebd 100644
--- a/trading/trading/data_panel/snapshot/lib/snapshot_schema.ml
+++ b/trading/trading/data_panel/snapshot/lib/snapshot_schema.ml
@@ -22,6 +22,8 @@ type field =
 [@@deriving sexp, compare, equal, show]
 
 let n_hist_buckets = 20
+let n_age_bands = 4
+let n_hist_cells = n_age_bands * n_hist_buckets
 
 let all_fields =
   [
@@ -43,7 +45,7 @@ let all_fields =
     Res_max_high_520w;
     Res_bars_seen;
   ]
-  @ List.init n_hist_buckets ~f:(fun k -> Res_hist k)
+  @ List.init n_hist_cells ~f:(fun k -> Res_hist k)
 
 let field_name = function
   | EMA_50 -> "EMA_50"
diff --git a/trading/trading/data_panel/snapshot/lib/snapshot_schema.mli b/trading/trading/data_panel/snapshot/lib/snapshot_schema.mli
index c6ce4f675..2e68431e6 100644
--- a/trading/trading/data_panel/snapshot/lib/snapshot_schema.mli
+++ b/trading/trading/data_panel/snapshot/lib/snapshot_schema.mli
@@ -64,9 +64,11 @@
 
     Precomputed point-in-time overhead-supply sketches, appended after
     [Adjusted_close] (same append discipline as the OHLCV addition; schema
-    width grows from 13 to 37). All values are weekly-cadence aggregates
+    width grows from 13 to 97: 4 scalar sketch columns + [n_hist_cells = 80]
+    age-banded histogram columns). All values are weekly-cadence aggregates
     computed causally from bars up to and including the row's day — see
-    [dev/plans/resistance-v2-supply-sketches-2026-07-15.md] §D1-D4:
+    [dev/plans/resistance-v2-supply-sketches-2026-07-15.md] §D1-D4 and the
+    age-banded histogram (lever f, sketch v3):
 
     - {!Res_max_high_130w} / {!Res_max_high_260w} / {!Res_max_high_520w}:
       maximum raw weekly high over the trailing 130/260/520 weekly bars
@@ -79,13 +81,24 @@
     - {!Res_bars_seen}: true count of weekly bars available up to the row's
       day, capped at 520 — the honest [Insufficient_history] input (a
       window-starved warehouse can no longer masquerade as virgin history).
-    - {!Res_hist k} for [k = 0 .. n_hist_buckets - 1]: trailing 130-weekly-bar
-      log-price histogram anchored at the row's raw close [C]. Bucket [k]
-      counts weekly bars whose mid-price [(high + low) / 2] falls in
-      [C * 2^(k/20), C * 2^((k+1)/20)) and whose high exceeds [C] — i.e.
-      supply sitting 0..100% above the row's price, ~3.5% per band. Bars
-      more than 2x above [C] are dropped (proximity-negligible; the max-high
-      family still detects non-virgin at any distance).
+    - {!Res_hist k} for [k = 0 .. n_hist_cells - 1]: {b age-banded}
+      log-price histogram anchored at the row's raw close [C]. The [n_hist_cells]
+      columns are laid out band-major: cell [k] holds age band
+      [k / n_hist_buckets] and price bucket [k mod n_hist_buckets]. The four
+      age bands (youngest first) cover a weekly-bar age relative to the row of
+      [0-26w / 26-78w / 78-130w / 130-520w] (half-open; the partial current week
+      is age 0). Within every band price bucket [b] counts weekly bars whose
+      mid-price [(high + low) / 2] falls in
+      [C * 2^(b/20), C * 2^((b+1)/20)) and whose high exceeds [C] — i.e. supply
+      sitting 0..100% above the row's price, ~3.5% per band. Bars more than 2x
+      above [C] are dropped (proximity-negligible; the max-high family still
+      detects non-virgin at any distance). Age decay is applied at SCORE time
+      by [Resistance_supply] per-band config weights, NOT baked in at build
+      time, so the decay is an [Overlay_validator] axis family (no warehouse
+      rebuild per value). Summing the three 0-130w bands reproduces the
+      pre-lever-f age-blind 130-weekly-bar histogram exactly, and the 130-520w
+      band makes older supply MEASURED rather than only floored by the max-high
+      horizons.
 
     Sketch cells are [Float.nan] when the row's raw close is non-positive or
     non-finite (corrupt bar guard). *)
@@ -111,9 +124,19 @@ type field =
 [@@deriving sexp, compare, equal, show]
 
 val n_hist_buckets : int
-(** [n_hist_buckets] is the number of {!Res_hist} bucket columns in the
-    canonical schema (20). [Res_hist k] is canonical only for
-    [0 <= k < n_hist_buckets]; {!all_fields} enumerates exactly that range. *)
+(** [n_hist_buckets] is the number of log-price buckets per age band in the
+    {!Res_hist} histogram (20). *)
+
+val n_age_bands : int
+(** [n_age_bands] is the number of weekly-bar age bands the {!Res_hist}
+    histogram is split into (4): [0-26w / 26-78w / 78-130w / 130-520w]. *)
+
+val n_hist_cells : int
+(** [n_hist_cells = n_age_bands * n_hist_buckets] is the total number of
+    {!Res_hist} columns in the canonical schema (80). [Res_hist k] is canonical
+    only for [0 <= k < n_hist_cells], laid out band-major (cell [k] is age band
+    [k / n_hist_buckets], price bucket [k mod n_hist_buckets]); {!all_fields}
+    enumerates exactly that range. *)
 
 val all_fields : field list
 (** [all_fields] enumerates every variant of {!field} in declaration order. Used
@@ -144,7 +167,7 @@ val create : fields:field list -> t
     well-defined) but produces a schema that no real snapshot can match. *)
 
 val default : t
-(** [default] is the canonical 37-field schema: every field in {!all_fields}
+(** [default] is the canonical 97-field schema: every field in {!all_fields}
     order. The single source of truth for snapshots produced by the offline
     pipeline. *)
 
diff --git a/trading/trading/data_panel/snapshot/test/test_snapshot.ml b/trading/trading/data_panel/snapshot/test/test_snapshot.ml
index a143af24a..84380d6a4 100644
--- a/trading/trading/data_panel/snapshot/test/test_snapshot.ml
+++ b/trading/trading/data_panel/snapshot/test/test_snapshot.ml
@@ -21,7 +21,9 @@ let test_create_ok _ =
             field
               (fun s -> Date.to_string s.Snapshot.date)
               (equal_to "2024-01-02");
-            field (fun s -> Array.length s.Snapshot.values) (equal_to 37);
+            field
+              (fun s -> Array.length s.Snapshot.values)
+              (equal_to (Snapshot_schema.n_fields Snapshot_schema.default));
           ]))
 
 let test_create_rejects_width_mismatch _ =
diff --git a/trading/trading/data_panel/snapshot/test/test_snapshot_schema.ml b/trading/trading/data_panel/snapshot/test/test_snapshot_schema.ml
index 6b7d77bd0..6cc47f1f6 100644
--- a/trading/trading/data_panel/snapshot/test/test_snapshot_schema.ml
+++ b/trading/trading/data_panel/snapshot/test/test_snapshot_schema.ml
@@ -48,10 +48,19 @@ let test_default_schema_locks_in_canonical_fields _ =
           equal_to Res_max_high_520w;
           equal_to Res_bars_seen;
         ]
-       @ List.init n_hist_buckets ~f:(fun k -> equal_to (Res_hist k))))
+       @ List.init n_hist_cells ~f:(fun k -> equal_to (Res_hist k))))
 
 let test_default_schema_n_fields _ =
-  assert_that (Snapshot_schema.n_fields Snapshot_schema.default) (equal_to 37)
+  assert_that (Snapshot_schema.n_fields Snapshot_schema.default) (equal_to 97)
+
+(* The age-banded histogram (lever f) is 4 age bands x 20 price buckets = 80
+   Res_hist columns, laid out band-major. *)
+let test_hist_layout_constants _ =
+  assert_that
+    ( Snapshot_schema.n_hist_buckets,
+      Snapshot_schema.n_age_bands,
+      Snapshot_schema.n_hist_cells )
+    (equal_to (20, 4, 80))
 
 (* The Phase A → Phase A.1 OHLCV addition deliberately bumps the schema hash —
    it is content-addressable, set-sensitive by construction. Pin both the
@@ -104,7 +113,7 @@ let test_field_name_round_trip _ =
           equal_to "Res_max_high_520w";
           equal_to "Res_bars_seen";
         ]
-       @ List.init Snapshot_schema.n_hist_buckets ~f:(fun k ->
+       @ List.init Snapshot_schema.n_hist_cells ~f:(fun k ->
            equal_to (Printf.sprintf "Res_hist_%02d" k))))
 
 let suite =
@@ -116,7 +125,8 @@ let suite =
          >:: test_compute_hash_field_set_sensitive;
          "default schema locks in canonical fields"
          >:: test_default_schema_locks_in_canonical_fields;
-         "default schema n_fields = 37" >:: test_default_schema_n_fields;
+         "default schema n_fields = 97" >:: test_default_schema_n_fields;
+         "hist layout constants (20/4/80)" >:: test_hist_layout_constants;
          "default schema hash differs from pre-OHLCV"
          >:: test_default_schema_hash_pinned_for_canonical_set;
          "index_of present and absent" >:: test_index_of_present_and_absent;
diff --git a/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml b/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
index 11adfbccb..684b0869d 100644
--- a/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
+++ b/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
@@ -2,18 +2,24 @@ open Core
 module Resistance_sketch = Snapshot_pipeline.Resistance_sketch
 
 (* Extract one day's scalar sketch (day index [i]) from the per-day sketch
-   columns. The column-major histogram [arrays.hist.(k).(i)] is transposed to
-   the per-bucket vector [Resistance_supply.sketch.hist], and the anchor is the
-   bar's raw close (the same value the snapshot [Close] column stores — see
-   [Resistance_sketch_reader]). *)
+   columns. The column-major band-major histogram [arrays.hist.(cell).(i)] is
+   transposed into the [Resistance_supply.sketch.hist_bands] age-band matrix
+   ([hist_bands.(band).(bucket)], cell [band * n_buckets + bucket]), and the
+   anchor is the bar's raw close (the same value the snapshot [Close] column
+   stores — see [Resistance_sketch_reader]). *)
 let _sketch_at ~(arrays : Resistance_sketch.t)
     ~(bars : Types.Daily_price.t array) ~i : Resistance_supply.sketch =
+  let n_bands = Resistance_supply.n_age_bands in
+  let n_buckets = Array.length arrays.hist / n_bands in
   {
     Resistance_supply.max_high_130w = arrays.max_high_130w.(i);
     max_high_260w = arrays.max_high_260w.(i);
     max_high_520w = arrays.max_high_520w.(i);
     bars_seen = arrays.bars_seen.(i);
-    hist = Array.map arrays.hist ~f:(fun col -> col.(i));
+    hist_bands =
+      Array.init n_bands ~f:(fun band ->
+          Array.init n_buckets ~f:(fun bucket ->
+              arrays.hist.((band * n_buckets) + bucket).(i)));
     anchor_close = bars.(i).Types.Daily_price.close_price;
   }
 
diff --git a/trading/trading/weinstein/snapshot/gen/test/test_live_resistance_sketch.ml b/trading/trading/weinstein/snapshot/gen/test/test_live_resistance_sketch.ml
index bebbdf24f..d98933693 100644
--- a/trading/trading/weinstein/snapshot/gen/test/test_live_resistance_sketch.ml
+++ b/trading/trading/weinstein/snapshot/gen/test/test_live_resistance_sketch.ml
@@ -66,11 +66,12 @@ let test_sketch_pins_known_cells _ =
               (fun (s : Resistance_supply.sketch) -> s.anchor_close)
               (float_equal 120.0);
             field
-              (fun (s : Resistance_supply.sketch) -> s.hist.(0))
+              (fun (s : Resistance_supply.sketch) -> s.hist_bands.(0).(0))
               (float_equal 1.0);
             field
               (fun (s : Resistance_supply.sketch) ->
-                Array.fold s.hist ~init:0.0 ~f:( +. ))
+                Array.fold s.hist_bands ~init:0.0 ~f:(fun acc band ->
+                    acc +. Array.fold band ~init:0.0 ~f:( +. )))
               (float_equal 1.0);
             field
               (fun (s : Resistance_supply.sketch) -> s.bars_seen)
diff --git a/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.ml b/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.ml
index 23285fca1..83d3711f6 100644
--- a/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.ml
+++ b/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.ml
@@ -3,6 +3,33 @@ module Snapshot_bar_views = Snapshot_runtime.Snapshot_bar_views
 module Snapshot_callbacks = Snapshot_runtime.Snapshot_callbacks
 module Snapshot_schema = Data_panel_snapshot.Snapshot_schema
 
+(* Reshape a flat band-major cell vector ([band * n_buckets + bucket]) into the
+   [Resistance_supply.sketch.hist_bands] age-band matrix. *)
+let _bands_of_flat cells ~n_buckets =
+  Array.init Snapshot_schema.n_age_bands ~f:(fun band ->
+      Array.init n_buckets ~f:(fun bucket ->
+          cells.((band * n_buckets) + bucket)))
+
+(* Read the histogram, detecting the warehouse width. A v4 (age-banded)
+   warehouse carries [n_hist_cells] columns; a v3 warehouse carries only the
+   [n_hist_buckets] age-blind columns (its trailing [Res_hist] cells are absent,
+   so the probe read fails). The v3 histogram maps to the youngest age band via
+   [hist_bands_of_legacy], scoring bit-identically under default band weights —
+   so existing v3 warehouses keep working with no rebuild. *)
+let _read_hist_bands ~read =
+  let n_buckets = Snapshot_schema.n_hist_buckets in
+  let n_cells = Snapshot_schema.n_hist_cells in
+  let read_cells n =
+    List.init n ~f:(fun k -> read (Snapshot_schema.Res_hist k)) |> Option.all
+  in
+  match read (Snapshot_schema.Res_hist (n_cells - 1)) with
+  | Some _ ->
+      Option.map (read_cells n_cells) ~f:(fun cells ->
+          _bands_of_flat (Array.of_list cells) ~n_buckets)
+  | None ->
+      Option.map (read_cells n_buckets) ~f:(fun flat ->
+          Resistance_supply.hist_bands_of_legacy (Array.of_list flat))
+
 let read_sketch ~(cb : Snapshot_callbacks.t) ~symbol ~as_of :
     Resistance_supply.sketch option =
   let read field =
@@ -16,18 +43,14 @@ let read_sketch ~(cb : Snapshot_callbacks.t) ~symbol ~as_of :
   let%bind max_high_520w = read Snapshot_schema.Res_max_high_520w in
   let%bind bars_seen = read Snapshot_schema.Res_bars_seen in
   let%bind anchor_close = read Snapshot_schema.Close in
-  let%map hist =
-    List.init Snapshot_schema.n_hist_buckets ~f:(fun k ->
-        read (Snapshot_schema.Res_hist k))
-    |> Option.all
-  in
+  let%map hist_bands = _read_hist_bands ~read in
   Resistance_supply.
     {
       max_high_130w;
       max_high_260w;
       max_high_520w;
       bars_seen;
-      hist = Array.of_list hist;
+      hist_bands;
       anchor_close;
     }
 
diff --git a/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.mli b/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.mli
index fbe7e6ae0..4c47b796c 100644
--- a/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.mli
+++ b/trading/trading/weinstein/strategy/lib/resistance_sketch_reader.mli
@@ -14,11 +14,21 @@ val read_sketch :
   as_of:Core.Date.t ->
   Resistance_supply.sketch option
 (** [read_sketch ~cb ~symbol ~as_of] reads the sketch columns
-    ([Res_max_high_130/260/520w], [Res_bars_seen], [Res_hist k] for
-    [k = 0 .. n_hist_buckets - 1], and [Close] as the histogram anchor) at
-    [(symbol, as_of)]. Returns [None] if ANY required cell read fails (missing
-    row, a schema without the sketch columns, or a decode error) — a partial
-    read never fabricates a sketch. *)
+    ([Res_max_high_130/260/520w], [Res_bars_seen], the [Res_hist] histogram, and
+    [Close] as the histogram anchor) at [(symbol, as_of)]. Returns [None] if ANY
+    required scalar cell read fails (missing row, a schema without the sketch
+    columns, or a decode error) — a partial read never fabricates a sketch.
+
+    {b Warehouse-width detection (v3 back-compat).} A v4 (age-banded) warehouse
+    carries [Snapshot_schema.n_hist_cells] histogram columns; the reader reads
+    all of them and reshapes into the {!Resistance_supply.sketch.hist_bands}
+    age-band matrix. An older v3 warehouse carries only the [n_hist_buckets]
+    age-blind columns (the trailing [Res_hist] cells are absent, so a probe read
+    of the last v4 cell fails); the reader falls back to reading those
+    [n_hist_buckets] cells and packs them into the youngest age band via
+    {!Resistance_supply.hist_bands_of_legacy}, which under default band weights
+    scores bit-identically to before lever f. Existing v3 warehouses therefore
+    keep working with no rebuild. *)
 
 val closure :
   ?snapshot_cb:Snapshot_callbacks.t ->
diff --git a/trading/trading/weinstein/strategy/test/test_resistance_sketch_reader.ml b/trading/trading/weinstein/strategy/test/test_resistance_sketch_reader.ml
index e10bac78a..e1159b8bb 100644
--- a/trading/trading/weinstein/strategy/test/test_resistance_sketch_reader.ml
+++ b/trading/trading/weinstein/strategy/test/test_resistance_sketch_reader.ml
@@ -5,9 +5,10 @@
     bypass by injecting [get_sketch] directly:
 
     - [read_sketch]: every required cell [Ok] -> [Some] sketch with the read
-      field values ([anchor_close] from the raw [Close] column; [hist] length
-      [= Snapshot_schema.n_hist_buckets]); ANY required cell read failing
-      (scalar or a histogram bucket via [Option.all]) -> [None] — a partial read
+      field values ([anchor_close] from the raw [Close] column; the age-banded
+      histogram reshaped into [n_age_bands] bands of [n_hist_buckets], with the
+      v3-width fallback packing the 20 age-blind columns into the youngest
+      band); ANY required scalar cell read failing -> [None] — a partial read
       never fabricates a sketch (the read-layer expression of "a window-starved
       warehouse can no longer masquerade as virgin").
     - [closure]: a [fun () -> None] thunk when [snapshot_cb] / [stock_symbol] is
@@ -36,14 +37,23 @@ let stub_value : Snapshot_schema.field -> float = function
   | _ -> 0.0
 
 (* A stub [Snapshot_callbacks.t] whose [read_field] returns [Ok (stub_value
-   field)], except any field in [fail_on] returns [Error NotFound]. The two
-   remaining closures are unused by [read_sketch] and fail loudly if touched. *)
-let stub_cb ?(fail_on = []) () : Snapshot_callbacks.t =
+   field)], except any field in [fail_on] returns [Error NotFound]. [hist_width]
+   models a warehouse's [Res_hist] column count: reads of [Res_hist k] for
+   [k >= hist_width] return [Error] (a v3 warehouse has [hist_width =
+   n_hist_buckets], a v4 has [n_hist_cells]). The two remaining closures are
+   unused by [read_sketch] and fail loudly if touched. *)
+let stub_cb ?(fail_on = []) ?(hist_width = Snapshot_schema.n_hist_cells) () :
+    Snapshot_callbacks.t =
   {
     Snapshot_callbacks.read_field =
       (fun ~symbol:_ ~date:_ ~field ->
-        if List.mem fail_on field ~equal:Snapshot_schema.equal_field then
-          Status.error_not_found "stub: field forced to fail"
+        let absent =
+          match field with
+          | Snapshot_schema.Res_hist k -> k >= hist_width
+          | _ -> false
+        in
+        if absent || List.mem fail_on field ~equal:Snapshot_schema.equal_field
+        then Status.error_not_found "stub: field forced to fail"
         else Ok (stub_value field));
     read_field_history =
       (fun ~symbol:_ ~from:_ ~until:_ ~field:_ ->
@@ -73,8 +83,10 @@ let empty_view : Snapshot_bar_views.weekly_view =
     n = 0;
   }
 
-(* Happy path: all cells Ok -> Some sketch whose fields equal the stubbed reads,
-   incl. anchor_close from the raw Close column and hist length = n_hist_buckets. *)
+(* Happy path (v4 warehouse): all 80 cells Ok -> Some sketch whose fields equal
+   the stubbed reads. The band-major histogram reshapes into [n_age_bands] bands
+   of [n_hist_buckets] each: cell [k] -> band [k / 20], bucket [k mod 20], so
+   [hist_bands.(0).(3)] = cell 3 = 3.0 and [hist_bands.(1).(0)] = cell 20 = 20. *)
 let test_read_sketch_all_ok_reads_fields _ =
   assert_that
     (Reader.read_sketch ~cb:(stub_cb ()) ~symbol:"AAPL" ~as_of)
@@ -97,11 +109,50 @@ let test_read_sketch_all_ok_reads_fields _ =
               (fun (s : Resistance_supply.sketch) -> s.anchor_close)
               (float_equal 150.0);
             field
-              (fun (s : Resistance_supply.sketch) -> Array.length s.hist)
+              (fun (s : Resistance_supply.sketch) -> Array.length s.hist_bands)
+              (equal_to Snapshot_schema.n_age_bands);
+            field
+              (fun (s : Resistance_supply.sketch) ->
+                Array.length s.hist_bands.(0))
               (equal_to Snapshot_schema.n_hist_buckets);
             field
-              (fun (s : Resistance_supply.sketch) -> s.hist.(3))
+              (fun (s : Resistance_supply.sketch) -> s.hist_bands.(0).(3))
+              (float_equal 3.0);
+            field
+              (fun (s : Resistance_supply.sketch) -> s.hist_bands.(1).(0))
+              (float_equal 20.0);
+            field
+              (fun (s : Resistance_supply.sketch) -> s.hist_bands.(3).(0))
+              (float_equal 60.0);
+          ]))
+
+(* v3 back-compat: a warehouse with only the 20 age-blind [Res_hist] columns
+   (the trailing v4 cells absent) reads via the width-detection fallback — the
+   20 cells pack into the youngest age band, the rest zero. [hist_bands.(0).(3)]
+   = cell 3 = 3.0; the older bands are empty (a NaN/absent cell never
+   fabricated). This is the "v3-shaped sketch reads with no rebuild" gate. *)
+let test_read_sketch_v3_width_packs_youngest_band _ =
+  assert_that
+    (Reader.read_sketch
+       ~cb:(stub_cb ~hist_width:Snapshot_schema.n_hist_buckets ())
+       ~symbol:"AAPL" ~as_of)
+    (is_some_and
+       (all_of
+          [
+            field
+              (fun (s : Resistance_supply.sketch) -> Array.length s.hist_bands)
+              (equal_to Snapshot_schema.n_age_bands);
+            field
+              (fun (s : Resistance_supply.sketch) -> s.hist_bands.(0).(3))
               (float_equal 3.0);
+            field
+              (fun (s : Resistance_supply.sketch) ->
+                Array.count s.hist_bands.(1) ~f:(fun c -> Float.(c <> 0.0)))
+              (equal_to 0);
+            field
+              (fun (s : Resistance_supply.sketch) ->
+                Array.count s.hist_bands.(3) ~f:(fun c -> Float.(c <> 0.0)))
+              (equal_to 0);
           ]))
 
 (* A failing scalar cell collapses the whole read to None. *)
@@ -154,8 +205,10 @@ let test_closure_reads_sketch_at_last_bar _ =
 let suite =
   "Resistance_sketch_reader"
   >::: [
-         "read_sketch all Ok reads fields"
+         "read_sketch all Ok reads fields (v4)"
          >:: test_read_sketch_all_ok_reads_fields;
+         "read_sketch v3 width packs youngest band"
+         >:: test_read_sketch_v3_width_packs_youngest_band;
          "read_sketch scalar cell error -> None"
          >:: test_read_sketch_scalar_cell_error_none;
          "read_sketch hist cell error -> None"

From 175512ff015a87101bdb41146b8ba235f159feb4 Mon Sep 17 00:00:00 2001
From: dayfine <difancpa@gmail.com>
Date: Sun, 19 Jul 2026 19:08:09 -0400
Subject: [PATCH 2/2] =?UTF-8?q?fix(review):=20address=20QC=20rework=20iter?=
 =?UTF-8?q?ation=201=20=E2=80=94=20extract=20histogram=20reshape=20helper?=
 =?UTF-8?q?=20(nesting=20depth)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../gen/lib/live_resistance_sketch.ml         | 25 +++++++++++--------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml b/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
index 684b0869d..43230301f 100644
--- a/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
+++ b/trading/trading/weinstein/snapshot/gen/lib/live_resistance_sketch.ml
@@ -1,25 +1,28 @@
 open Core
 module Resistance_sketch = Snapshot_pipeline.Resistance_sketch
 
+(* Transpose day [i]'s band-major histogram columns [arrays.hist.(cell).(i)]
+   (cell [band * n_buckets + bucket]) into the [Resistance_supply.sketch]
+   age-band matrix [hist_bands.(band).(bucket)]. Extracted from [_sketch_at] to
+   keep that record literal within the nesting limit. *)
+let _hist_bands_at ~(arrays : Resistance_sketch.t) ~i =
+  let n_bands = Resistance_supply.n_age_bands in
+  let n_buckets = Array.length arrays.hist / n_bands in
+  let cell ~band ~bucket = arrays.hist.((band * n_buckets) + bucket).(i) in
+  Array.init n_bands ~f:(fun band ->
+      Array.init n_buckets ~f:(fun bucket -> cell ~band ~bucket))
+
 (* Extract one day's scalar sketch (day index [i]) from the per-day sketch
-   columns. The column-major band-major histogram [arrays.hist.(cell).(i)] is
-   transposed into the [Resistance_supply.sketch.hist_bands] age-band matrix
-   ([hist_bands.(band).(bucket)], cell [band * n_buckets + bucket]), and the
-   anchor is the bar's raw close (the same value the snapshot [Close] column
-   stores — see [Resistance_sketch_reader]). *)
+   columns. The anchor is the bar's raw close (the same value the snapshot
+   [Close] column stores — see [Resistance_sketch_reader]). *)
 let _sketch_at ~(arrays : Resistance_sketch.t)
     ~(bars : Types.Daily_price.t array) ~i : Resistance_supply.sketch =
-  let n_bands = Resistance_supply.n_age_bands in
-  let n_buckets = Array.length arrays.hist / n_bands in
   {
     Resistance_supply.max_high_130w = arrays.max_high_130w.(i);
     max_high_260w = arrays.max_high_260w.(i);
     max_high_520w = arrays.max_high_520w.(i);
     bars_seen = arrays.bars_seen.(i);
-    hist_bands =
-      Array.init n_bands ~f:(fun band ->
-          Array.init n_buckets ~f:(fun bucket ->
-              arrays.hist.((band * n_buckets) + bucket).(i)));
+    hist_bands = _hist_bands_at ~arrays ~i;
     anchor_close = bars.(i).Types.Daily_price.close_price;
   }