diff --git a/tools/unit_test_matrix.py b/tools/unit_test_matrix.py
new file mode 100644
index 0000000..3005007
--- /dev/null
+++ b/tools/unit_test_matrix.py
@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+"""Generate a reproducible validation matrix for MACA GPU testing."""
+
+from __future__ import annotations
+
+
+import argparse
+import itertools
+import json
+
+
+DEFAULT_TESTS = ["unit_test/test_rms_norm.py", "unit_test/test_fused_moe_gate.py"]
+DIMENSIONS = {"dtype": ["fp16", "bf16"], "scope": ["smoke", "full"]}
+
+
+def build_matrix(tests: list[str]) -> list[dict[str, str]]:
+    keys = list(DIMENSIONS)
+    rows = []
+    for test in tests:
+        for values in itertools.product(*(DIMENSIONS[k] for k in keys)):
+            row = {"test": test}
+            row.update(dict(zip(keys, values)))
+            rows.append(row)
+    return rows
+
+
+def self_test() -> None:
+    rows = build_matrix(DEFAULT_TESTS[:1])
+    if not rows or "test" not in rows[0]:
+        raise RuntimeError(f"self-test failed: {rows}")
+    print(json.dumps({"ok": True, "rows": len(rows)}, ensure_ascii=False))
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--test", action="append", default=[], help="Override or extend test names.")
+    parser.add_argument("--self-test", action="store_true")
+    args = parser.parse_args()
+    if args.self_test:
+        self_test()
+        return 0
+    tests = args.test or DEFAULT_TESTS
+    print(json.dumps(build_matrix(tests), ensure_ascii=False, indent=2))
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())