diff --git a/index/src/pixelrag_index/pipelines.py b/index/src/pixelrag_index/pipelines.py
index f943ec8..0f4800f 100644
--- a/index/src/pixelrag_index/pipelines.py
+++ b/index/src/pixelrag_index/pipelines.py
@@ -217,7 +217,10 @@ def main():
     )
     parser.add_argument("--output", "-o", default=None, help="Output directory")
     parser.add_argument(
-        "--device", default=None, choices=["cpu", "cuda"], help="Embedding device"
+        "--device",
+        default=None,
+        choices=["auto", "cpu", "mps", "cuda"],
+        help="Embedding device (default: from config; auto-detects cuda/mps/cpu)",
     )
     parser.add_argument(
         "--limit", "-n", type=int, default=None, help="Max documents to process"
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 1c43df2..2d32016 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -32,6 +32,14 @@ def test_pixelrag_umbrella_help():
         assert stage in out
 
 
+def test_index_build_device_choices():
+    # CLI must offer every device the embedder supports (auto/mps were missing).
+    # Assert the argparse-rendered choices token, not loose words in the help prose.
+    r = _run("pixelrag", "index", "build", "--help")
+    assert r.returncode == 0
+    assert "{auto,cpu,mps,cuda}" in r.stdout
+
+
 def test_pixelrag_unknown_stage_errors():
     r = _run("pixelrag", "definitely-not-a-stage")
     assert r.returncode != 0