diff --git a/evolution/hardware_optimizer.py b/evolution/hardware_optimizer.py
index 27866e1..67dd7da 100644
--- a/evolution/hardware_optimizer.py
+++ b/evolution/hardware_optimizer.py
@@ -1,5 +1,29 @@
-"""Phase 19: Hardware-Aware Inference Optimization.
-Part of the TurboQuant suite for local inference excellence.
+"""Backward-compatible shim for hardware-aware quantization selection.
+
+The original Phase 19 placeholder `hardware_optimizer.py` never shipped real
+logic. The canonical implementation now lives in `evolution.quant_selector`.
+This shim preserves the legacy import path for any downstream callers while
+making `quant_selector.py` the single source of truth.
 """
-import logging
-# ... (rest of the code)
+
+from evolution.quant_selector import (  # noqa: F401
+    HardwareInfo,
+    QuantLevel,
+    QuantSelection,
+    QUANT_LEVELS,
+    detect_hardware,
+    estimate_kv_cache_gb,
+    estimate_model_memory_gb,
+    select_quant_level,
+)
+
+__all__ = [
+    "HardwareInfo",
+    "QuantLevel",
+    "QuantSelection",
+    "QUANT_LEVELS",
+    "detect_hardware",
+    "estimate_kv_cache_gb",
+    "estimate_model_memory_gb",
+    "select_quant_level",
+]
diff --git a/tests/test_hardware_optimizer.py b/tests/test_hardware_optimizer.py
new file mode 100644
index 0000000..72358a1
--- /dev/null
+++ b/tests/test_hardware_optimizer.py
@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+"""Tests for hardware_optimizer compatibility shim."""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
+
+from evolution import hardware_optimizer, quant_selector
+
+
+def test_hardware_optimizer_reexports_quant_selector_api():
+    assert hardware_optimizer.select_quant_level is quant_selector.select_quant_level
+    assert hardware_optimizer.detect_hardware is quant_selector.detect_hardware
+    assert hardware_optimizer.HardwareInfo is quant_selector.HardwareInfo
+    assert hardware_optimizer.QuantSelection is quant_selector.QuantSelection
+
+
+def test_hardware_optimizer_exports_quant_level_definitions():
+    assert hardware_optimizer.QUANT_LEVELS is quant_selector.QUANT_LEVELS
+    assert hardware_optimizer.QuantLevel is quant_selector.QuantLevel