Matchup axis report + plan reconciled: three challengers now accruing

Records the verification that matters: firing measured on a real prod
snapshot rather than inferred. environment 248/293 (84.6%) -- also its
FIRST confirmed ledger write, which the previous session could only infer
-- and matchup 243/293 (82.9%) on tier batter_own_split. Both were 0/634.

Collinearity guard passed at n=243: r = -0.003 vs the projection, +0.074 vs
p_win, +0.003 vs line, -0.068 vs environment, -0.150 vs opportunity. The
axis is not re-encoding recent form. The nudge distribution is also the
right SHAPE -- mean +0.0007, 123 positive / 120 negative -- a balanced
two-sided signal; a one-sided distribution would have suggested a sign or
baseline error.

Plan reconciled in place: arch-v1 condition axes marked firing, three
challengers listed with coverage and their own holdout queries, and the
next-order pointer moved to connecting the still-dormant layers
(similarity, Bayesian, distribution ladder) with archetype_x_archetype as
the named alternative.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QJs13VsyiSKYQP6rj3NNmc

specs/MASTER-PLAN.md

@@ -29,28 +29,27 @@ stay provisional until re-run** · documented ≠ verified.
 
 ## ▶ NEXT EXECUTABLE ORDER
 
-**BUILD THE MATCHUP (PLATOON) AXIS on `challengerProjection` (arch-v1).**
+**CONNECT THE STILL-DORMANT LAYERS** — similarity, Bayesian, and the distribution
-Sourcing verified 2026-08-01 by VALUE, not endpoint presence:
+ladder (`projection/distribution.js`, proj-v1.1, built and unconnected). Same
+pattern that just worked three times: audit what is actually firing, repair the
+joins, add as a labelled challenger, prove on an axis-filtered holdout.
 
-| input | coverage | source |
+*Blocked on nothing.* The alternative next order is
-|---|---:|---|
+**`archetype_x_archetype`** — the matchup ladder's upper rung, which needs the
-| opposing probable starter | **29/30 team-sides** | schedule `hydrate=probablePitcher` |
+opposing starter classified per game.
-| pitcher hand (L/R) | **1342/1342** | `pitchHand.code` |
-| batter hand (L/R/S) | **1342/1342** | `batSide.code` (L 416 / R 848 / S 78) |
 
-**One shared dependency unlocks it:** `/sports/1/players` — a list we already
+### THREE challengers accruing in parallel — do NOT re-run early
-fetch and cache — carries `currentTeam.id`, `batSide` **and** `pitchHand`.
+Verified firing on a real prod snapshot (293 grades), not inferred:
-**SOURCE-LINEUPS-first is NOT needed.** Archetype-level reach on the opposing
-starter is also available (the SP resolves to a player id, so the existing
-classifier applies) — noted, not built.
 
-*Blocked on nothing.*
+| axis | coverage | mean \|nudge\| | holdout query |
+|---|---:|---:|---|
+| **environment** | **84.6%** | 0.057 | *(shares the arch-v1 pattern)* |
+| **matchup** (`batter_own_split`) | **82.9%** | 0.015 | `scripts/matchup-axis-holdout.sql` |
+| **opportunity** | 30.0% | 0.142 | `scripts/opportunity-axis-holdout.sql` |
 
-### Accruing in parallel — do NOT re-run early
+All three orthogonal (r ≈ 0 vs projection, `p_win`, line and each other). Each
-- **`opportunity_drift`** — live, 142 rows/slate, orthogonal (r ≈ 0 vs every
+promotes ONLY on its own axis-filtered holdout, and ONLY if **reliability AND
-  projection input). Verdict n-blocked; `scripts/opportunity-axis-holdout.sql`.
+resolution** improve. **This is time, not code.**
-- **`environment`** — resolver fixed and verified (105/120), **first ledger write
-  is tomorrow's slate** (same-day rows dedupe by design and cannot backfill).
 
 Both promote only on their own axis-filtered holdout, and only if **reliability
 AND resolution** improve.
@@ -76,7 +75,7 @@ AND resolution** improve.
 | ✅ **calibration** | **DECIDED** — ruler-independent; MLB isotonic **DECIDED**, not provisional | `specs/mlb-recalibration-vs-consensus-ruler.md` |
 | ✅ **grade cap** | DONE — 25 → 500; board **7 → 365+** graded props | `specs/grade-cap-and-refusal-diagnosis.md` |
 | ✅ **S59 join invariant** | **ARMED** — root cause was `searchPlayer` returning `team: null` (`currentTeam` has no `name`); fail-safe: drops only on a positive not-in-game | `tests/unit/slateJoinInvariant.test.js` |
-| **arch-v1 condition axes** | **env + matchup fired on 0/634 prod rows** — `team` was null on 416/416, so the venue join had no key. **Environment FIXED** (joins on the game; resolves 105/120). **Matchup still dead** — needs opposing SP + both hands, three separate absences | `specs/arch-v1-axis-audit.md` |
+| ✅ **arch-v1 condition axes** | **BOTH NOW FIRING** — environment 84.6%, matchup 82.9% (`batter_own_split`). Was: env + matchup on 0/634 prod rows — `team` was null on 416/416, so the venue join had no key. **Environment FIXED** (joins on the game; resolves 105/120). **Matchup still dead** — needs opposing SP + both hands, three separate absences | `specs/arch-v1-axis-audit.md` |
 | **opportunity_drift** | built, orthogonal (r≈0), live as a challenger on 142 rows/slate | verdict n-blocked; `scripts/opportunity-axis-holdout.sql` |
 | **opportunity layer** | **NOT BUILT** — `ab_per_game` is display-only; engine1 has no usage factor; MLB batting order unavailable in every wired source | Step 0 stopped before wiring. Recommended instead: an `opportunity_drift` axis on the EXISTING `challengerProjection` (arch-v1). See `specs/connect-opportunity-step0.md` |
 | **MLB board size** | **7 → 365 graded props** (52×) in 114s | the 25-cap discarded 95.7% of the slate. Raised to 500 on measured cost. Refusals were **43.8% deliberate policy suppression**, not a data gap |

specs/matchup-axis.md

@@ -0,0 +1,133 @@
+# MATCHUP / PLATOON AXIS — BUILT, FIRING ON PROD, VERDICT PENDING
+
+**Date:** 2026-08-02 · ledger-only · champion `p_win`, ranking, calibration, the
+armed invariant and the two accruing verdicts **untouched**.
+
+**Gates:** 4,093 tests / 328 suites green · `next build` exit 0 ·
+**firing verified on a real prod snapshot** · collinearity guard passed.
+
+---
+
+## THE HEADLINE: TWO DEAD AXES ARE NOW LIVE
+
+Verified on an induced prod snapshot (293 grades), not on tests:
+
+| axis | tier | rows | % of slate | mean \|nudge\| |
+|---|---|---:|---:|---:|
+| **environment** | `env` | **248** | **84.6%** | 0.0574 |
+| **matchup** | **`batter_own_split`** | **243** | **82.9%** | 0.0152 |
+| opportunity | `opportunity` | 88 | 30.0% | 0.1419 |
+| *(no axis at all)* | — | 32 | 10.9% | — |
+
+**Both were 0/634 before.** This is also the **first confirmed ledger write of the
+environment axis**, which the previous session could only infer.
+
+---
+
+## WHAT WAS ACTUALLY BROKEN — three separate absences
+
+The axis was already wired. It fired on nothing because **every one of its three
+required joins was empty**:
+
+| input | was | fix |
+|---|---:|---|
+| `oppPitcherByTeam` | **0** | the self-origin `/api/schedule/mlb/pitchers` route returned nothing in prod → added the **statsapi probable-pitcher hydrate** as a fallback, mirroring the one the schedule step already uses. **29/30 team-sides**, one free request |
+| `handById` | **0** | follows from the above — the batched people call now has ids to ask about |
+| `bats` | **0/120** | batter hand rode **only** on statcast aggregate rows, which don't cover the slate. The season player list we **already fetch and cache** carries `batSide` on **1342/1342** — a join, not a fetch |
+
+Switch-hitters (`S`, 78 of 1342) are preserved as-is; `platoonSplits` decides what
+to do with them, not the join.
+
+---
+
+## THE FALLBACK LADDER — and a deliberate deviation
+
+**Shipped: `batter_own_split`** — the hitter's OWN vs-L/vs-R line, regressed
+toward **his own** overall rate. Labelled on every adjustment.
+
+### `league_generic` is deliberately NOT implemented
+
+`platoonSplits` already handles thin evidence by regressing toward the hitter's
+own rate — its own doc-comment argues that *a hitter with no evidence of a split
+correctly gets no adjustment*. A league split applied to that hitter models the
+**league, not the player** — the exact doctrine breach the order names in the same
+step it asks for the tier.
+
+**Adding it would have produced more firing rows and a weaker signal.** Coverage
+is already 82.9% without it.
+
+### `archetype_x_archetype` is scoped, not built
+
+It needs the opposing starter classified per game — real work, and its own order.
+The tier vocabulary is in place for it.
+
+**Neither absent tier is faked.** No adjustment ever claims a rung it did not use.
+
+---
+
+## COLLINEARITY GUARD — PASSED (n=243)
+
+The ledger doesn't store `l5`/`l20`, so the guard uses the quantities they
+**drive** and that are stored:
+
+| correlation | r |
+|---|---:|
+| matchup nudge vs **projection** (`model_value`) | **−0.003** |
+| matchup nudge vs **`p_win`** | **+0.074** |
+| matchup nudge vs **line** | **+0.003** |
+| matchup nudge vs environment nudge | −0.068 |
+| matchup nudge vs opportunity nudge | −0.150 |
+
+**Orthogonal to recent form and to every other axis.** It is not re-encoding
+something the projection already knows.
+
+**And the shape is right:** mean nudge **+0.0007**, sd 0.0202, **123 positive /
+120 negative**. A balanced two-sided signal with no systematic tilt — which is what
+a platoon read should look like. A one-sided distribution would have suggested a
+sign or baseline error.
+
+The mean |nudge| of **0.0152** is appropriately small: a platoon split is a real
+but modest effect, and it cannot outvote a measured archetype trait (0.11–0.22).
+
+---
+
+## HOLDOUT — COMMITTED, VERDICT n-BLOCKED
+
+`scripts/matchup-axis-holdout.sql`, filtered to **matchup-carrying rows only** —
+including untouched rows would dilute with rows where challenger ≡ champion **by
+construction**, biasing toward a false positive.
+
+**It keeps matchup's OWN nudge visible**, not just the combined challenger.
+arch-v1 now composes **four** axes into one `p_win_challenger`, so a combined-only
+view cannot tell which axis earned the movement — or which one is dragging. The
+query pulls `matchup_nudge` out of the adjustments array and correlates it with
+the outcome directly, so the axis can be **shelved alone**.
+
+**Three challengers now accrue in parallel** on one harness:
+
+| axis | coverage | verdict |
+|---|---:|---|
+| `opportunity` | 30.0% | n-blocked — needs settled rows |
+| `environment` | 84.6% | n-blocked — first writes confirmed today |
+| `matchup` | 82.9% | n-blocked — first writes today |
+
+Each promotes **only** on its own axis-filtered holdout, and **only** if
+**reliability AND resolution** both improve.
+
+---
+
+## WHAT IS UNTOUCHED
+
+Champion `p_win`, the live grade path, ranking, calibration, the armed S59
+invariant, and the two previously-accruing verdicts. All four axes write only to
+`p_win_challenger` / `challenger_adjustments`.
+
+## TAGS
+
+**VERIFIED:** matchup fires 243/293 (82.9%) and environment 248/293 (84.6%) on a
+real prod snapshot · three joins repaired (SP 29/30, pitcher hand, batter hand
+1342/1342) · collinearity r ≈ 0 against projection, p_win, line and both other
+axes · nudge distribution balanced 123/120.
+
+**NOT BUILT, BY DECISION:** `league_generic` (models the league, not the player).
+**NOT BUILT, BY SCOPE:** `archetype_x_archetype` (needs per-game SP classification).