diff --git a/docs/research/sr-levels-and-exits.md b/docs/research/sr-levels-and-exits.md
index 5dd3f01..3a7d48f 100644
--- a/docs/research/sr-levels-and-exits.md
+++ b/docs/research/sr-levels-and-exits.md
@@ -412,10 +412,22 @@ Detector evidence (`sources`, rejection count, last rejection age) stays in the
 pure backtest objects. It is deliberately not migrated into the production DB
 schema until a variant passes validation.
 
-Run the training matrix with `--entry-end 2024-06-30 --sr-audit`, choose one arm,
-and record that lock before running exactly control and the locked arm with
-`--entry-start 2024-07-01`. Use `scripts/compare_sr_variants.py` to produce the
-paired cohort CSV and summary JSON.
+The cross-platform matrix runner is only an orchestrator around the existing
+`run_backtest_snapshot.py`; it contains no duplicate backtest logic. On macOS:
+
+```bash
+.venv/bin/python scripts/run_sr_v2_matrix.py train --workers 14
+```
+
+Choose one arm and record that lock before running exactly control and that arm:
+
+```bash
+.venv/bin/python scripts/run_sr_v2_matrix.py validate \
+  --locked-arm confirmed_rounds --workers 14
+```
+
+Replace `confirmed_rounds` with the recorded winner. The validation command also
+calls `scripts/compare_sr_variants.py` to produce the paired cohort CSV and JSON.
 
 The post-2024 interval has informed earlier research, so this is validation rather
 than a pristine holdout; do not sweep variants on it. No deployment follows
diff --git a/scripts/run_sr_v2_matrix.py b/scripts/run_sr_v2_matrix.py
new file mode 100644
index 0000000..39a619e
--- /dev/null
+++ b/scripts/run_sr_v2_matrix.py
@@ -0,0 +1,128 @@
+"""Run the S/R v2 training matrix or one locked validation comparison.
+
+This is a cross-platform orchestrator around ``run_backtest_snapshot.py``. It
+contains no backtest logic; every arm still runs through the production-parity
+Python harness.
+"""
+
+from __future__ import annotations
+
+import argparse
+import subprocess
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+RUNNER = ROOT / "scripts" / "run_backtest_snapshot.py"
+COMPARE = ROOT / "scripts" / "compare_sr_variants.py"
+TRAINING_ARMS = (
+    "production_control",
+    "rr_aligned_control",
+    "rewrite",
+    "soft_zones",
+    "confirmed_rounds",
+    "gate_v2",
+)
+LOCKABLE_ARMS = TRAINING_ARMS[1:]
+
+
+def _add_common(parser: argparse.ArgumentParser) -> None:
+    parser.add_argument(
+        "--snapshot",
+        default="backtest_snapshots/prod.sqlite",
+        help="Local SQLite snapshot path.",
+    )
+    parser.add_argument("--workers", type=int, default=7)
+
+
+def _args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(description=__doc__)
+    commands = parser.add_subparsers(dest="command", required=True)
+    train = commands.add_parser("train", help="Run all arms before 2024-07-01.")
+    _add_common(train)
+    validate = commands.add_parser(
+        "validate",
+        help="Run production control and one locked arm from 2024-07-01.",
+    )
+    _add_common(validate)
+    validate.add_argument("--locked-arm", required=True, choices=LOCKABLE_ARMS)
+    return parser.parse_args()
+
+
+def _run_arm(
+    arm: str,
+    snapshot: str,
+    workers: int,
+    *,
+    entry_flag: str,
+    entry_date: str,
+    output: Path,
+) -> None:
+    print(f"Running S/R arm: {arm}", flush=True)
+    subprocess.run(
+        [
+            sys.executable,
+            str(RUNNER),
+            snapshot,
+            "--workers", str(workers),
+            "--allow-spawn",
+            "--sr-variant", arm,
+            entry_flag, entry_date,
+            "--sr-audit",
+            "--out", str(output),
+        ],
+        cwd=ROOT,
+        check=True,
+    )
+
+
+def _train(args: argparse.Namespace) -> None:
+    for arm in TRAINING_ARMS:
+        _run_arm(
+            arm,
+            args.snapshot,
+            args.workers,
+            entry_flag="--entry-end",
+            entry_date="2024-06-30",
+            output=ROOT / "reports" / f"backtest-sr-v2-train-{arm}.json",
+        )
+    print("Training matrix complete. Lock one arm before running validation.")
+
+
+def _validate(args: argparse.Namespace) -> None:
+    reports: dict[str, Path] = {}
+    for arm in ("production_control", args.locked_arm):
+        output = ROOT / "reports" / f"backtest-sr-v2-validation-{arm}.json"
+        reports[arm] = output
+        _run_arm(
+            arm,
+            args.snapshot,
+            args.workers,
+            entry_flag="--entry-start",
+            entry_date="2024-07-01",
+            output=output,
+        )
+    subprocess.run(
+        [
+            sys.executable,
+            str(COMPARE),
+            str(reports["production_control"]),
+            str(reports[args.locked_arm]),
+            "--out-csv", str(ROOT / "reports" / "sr-v2-validation-cohorts.csv"),
+            "--out-json", str(ROOT / "reports" / "sr-v2-validation-comparison.json"),
+        ],
+        cwd=ROOT,
+        check=True,
+    )
+
+
+def main() -> None:
+    args = _args()
+    if args.command == "train":
+        _train(args)
+    else:
+        _validate(args)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/run_sr_v2_training_matrix.ps1 b/scripts/run_sr_v2_training_matrix.ps1
deleted file mode 100644
index 066c169..0000000
--- a/scripts/run_sr_v2_training_matrix.ps1
+++ /dev/null
@@ -1,32 +0,0 @@
-param(
-    [string]$Snapshot = "backtest_snapshots\prod.sqlite",
-    [string]$Python = ".venv\Scripts\python.exe",
-    [int]$Workers = 7
-)
-
-$ErrorActionPreference = "Stop"
-$arms = @(
-    "production_control",
-    "rr_aligned_control",
-    "rewrite",
-    "soft_zones",
-    "confirmed_rounds",
-    "gate_v2"
-)
-
-foreach ($arm in $arms) {
-    $output = "reports\backtest-sr-v2-train-$arm.json"
-    Write-Host "Running S/R training arm: $arm"
-    & $Python scripts\run_backtest_snapshot.py $Snapshot `
-        --workers $Workers `
-        --allow-spawn `
-        --sr-variant $arm `
-        --entry-end 2024-06-30 `
-        --sr-audit `
-        --out $output
-    if ($LASTEXITCODE -ne 0) {
-        throw "S/R training arm failed: $arm"
-    }
-}
-
-Write-Host "Training matrix complete. Lock one arm before running validation."
diff --git a/scripts/run_sr_v2_validation.ps1 b/scripts/run_sr_v2_validation.ps1
deleted file mode 100644
index 0c49b74..0000000
--- a/scripts/run_sr_v2_validation.ps1
+++ /dev/null
@@ -1,34 +0,0 @@
-param(
-    [Parameter(Mandatory = $true)]
-    [ValidateSet("rr_aligned_control", "rewrite", "soft_zones", "confirmed_rounds", "gate_v2")]
-    [string]$LockedArm,
-    [string]$Snapshot = "backtest_snapshots\prod.sqlite",
-    [string]$Python = ".venv\Scripts\python.exe",
-    [int]$Workers = 7
-)
-
-$ErrorActionPreference = "Stop"
-$arms = @("production_control", $LockedArm)
-foreach ($arm in $arms) {
-    $output = "reports\backtest-sr-v2-validation-$arm.json"
-    Write-Host "Running locked S/R validation arm: $arm"
-    & $Python scripts\run_backtest_snapshot.py $Snapshot `
-        --workers $Workers `
-        --allow-spawn `
-        --sr-variant $arm `
-        --entry-start 2024-07-01 `
-        --sr-audit `
-        --out $output
-    if ($LASTEXITCODE -ne 0) {
-        throw "S/R validation arm failed: $arm"
-    }
-}
-
-& $Python scripts\compare_sr_variants.py `
-    reports\backtest-sr-v2-validation-production_control.json `
-    "reports\backtest-sr-v2-validation-$LockedArm.json" `
-    --out-csv reports\sr-v2-validation-cohorts.csv `
-    --out-json reports\sr-v2-validation-comparison.json
-if ($LASTEXITCODE -ne 0) {
-    throw "S/R validation comparison failed"
-}