diff --git a/tests/test_cli.py b/tests/test_cli.py
index cae8ec8..2b568b1 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -54,6 +54,11 @@ def run_main(monkeypatch, argv):
     cli.main()
 
 
+def patch_soundfile_write(monkeypatch):
+    soundfile_stub = types.SimpleNamespace(write=lambda *args, **kwargs: None)
+    monkeypatch.setitem(sys.modules, "soundfile", soundfile_stub)
+
+
 def test_parser_defaults_to_voxcpm2():
     parser = cli._build_parser()
     args = parser.parse_args(["design", "--text", "hello", "--output", "out.wav"])
@@ -70,7 +75,7 @@ def test_load_model_respects_no_optimize_for_local_model(monkeypatch):
             calls["kwargs"] = kwargs
             self.tts_model = DummyTTSModel()
 
-    monkeypatch.setattr(cli, "VoxCPM", FakeVoxCPM)
+    monkeypatch.setattr(core_stub, "VoxCPM", FakeVoxCPM)
     args = cli._build_parser().parse_args(
         [
             "design",
@@ -99,7 +104,7 @@ def test_load_model_defaults_optimize_for_hf(monkeypatch):
             calls["kwargs"] = kwargs
             return DummyModel()
 
-    monkeypatch.setattr(cli, "VoxCPM", FakeVoxCPM)
+    monkeypatch.setattr(core_stub, "VoxCPM", FakeVoxCPM)
     args = cli._build_parser().parse_args(
         [
             "design",
@@ -125,7 +130,7 @@ def test_load_model_respects_no_optimize_for_hf(monkeypatch):
             calls["kwargs"] = kwargs
             return DummyModel()
 
-    monkeypatch.setattr(cli, "VoxCPM", FakeVoxCPM)
+    monkeypatch.setattr(core_stub, "VoxCPM", FakeVoxCPM)
     args = cli._build_parser().parse_args(
         [
             "design",
@@ -152,7 +157,7 @@ def test_load_model_passes_explicit_device_to_hf(monkeypatch):
             calls["kwargs"] = kwargs
             return DummyModel()
 
-    monkeypatch.setattr(cli, "VoxCPM", FakeVoxCPM)
+    monkeypatch.setattr(core_stub, "VoxCPM", FakeVoxCPM)
     args = cli._build_parser().parse_args(
         [
             "design",
@@ -173,7 +178,7 @@ def test_load_model_passes_explicit_device_to_hf(monkeypatch):
 def test_design_subcommand_applies_control(monkeypatch, tmp_path):
     dummy_model = DummyModel()
     monkeypatch.setattr(cli, "load_model", lambda args: dummy_model)
-    monkeypatch.setattr(cli.sf, "write", lambda *args, **kwargs: None)
+    patch_soundfile_write(monkeypatch)
 
     run_main(
         monkeypatch,
@@ -201,7 +206,7 @@ def test_clone_subcommand_reads_prompt_file(monkeypatch, tmp_path):
     prompt_file.write_text("prompt transcript\n", encoding="utf-8")
 
     monkeypatch.setattr(cli, "load_model", lambda args: dummy_model)
-    monkeypatch.setattr(cli.sf, "write", lambda *args, **kwargs: None)
+    patch_soundfile_write(monkeypatch)
 
     run_main(
         monkeypatch,
@@ -273,7 +278,7 @@ def test_clone_rejects_reference_audio_for_v1_hf_model_id(monkeypatch, tmp_path)
 def test_legacy_root_args_still_work_and_warn(monkeypatch, tmp_path, capsys):
     dummy_model = DummyModel()
     monkeypatch.setattr(cli, "load_model", lambda args: dummy_model)
-    monkeypatch.setattr(cli.sf, "write", lambda *args, **kwargs: None)
+    patch_soundfile_write(monkeypatch)
 
     run_main(
         monkeypatch,
@@ -296,7 +301,7 @@ def test_batch_subcommand_applies_control(monkeypatch, tmp_path):
     input_file.write_text("hello\nworld\n", encoding="utf-8")
 
     monkeypatch.setattr(cli, "load_model", lambda args: dummy_model)
-    monkeypatch.setattr(cli.sf, "write", lambda *args, **kwargs: None)
+    patch_soundfile_write(monkeypatch)
 
     run_main(
         monkeypatch,
@@ -325,7 +330,7 @@ def test_legacy_clone_with_prompt_file_still_works(monkeypatch, tmp_path, capsys
     prompt_file.write_text("legacy transcript", encoding="utf-8")
 
     monkeypatch.setattr(cli, "load_model", lambda args: dummy_model)
-    monkeypatch.setattr(cli.sf, "write", lambda *args, **kwargs: None)
+    patch_soundfile_write(monkeypatch)
 
     run_main(
         monkeypatch,