diff --git a/mergify_cli/ci/cli.py b/mergify_cli/ci/cli.py
index 9ee84bd..78ae31b 100644
--- a/mergify_cli/ci/cli.py
+++ b/mergify_cli/ci/cli.py
@@ -217,6 +217,14 @@ def git_refs() -> None:
     default=".mergify.yml",
     help="Path to YAML config file.",
 )
+@click.option(
+    "--base",
+    help="The base git reference to use to look for changed files",
+)
+@click.option(
+    "--head",
+    help="The head git reference to use to look for changed files",
+)
 @click.option(
     "--write",
     "-w",
@@ -226,9 +234,17 @@ def git_refs() -> None:
 def scopes(
     config_path: str,
     write: str | None = None,
+    head: str | None = None,
+    base: str | None = None,
 ) -> None:
+    ref = git_refs_detector.detect()
     try:
-        scopes = scopes_cli.detect(config_path=config_path)
+        scopes = scopes_cli.detect(
+            config_path=config_path,
+            base=base or ref.base,
+            head=head or ref.head,
+            is_merge_queue=ref.is_merge_queue,
+        )
     except scopes_exc.ScopesError as e:
         raise click.ClickException(str(e)) from e
 
diff --git a/mergify_cli/ci/scopes/cli.py b/mergify_cli/ci/scopes/cli.py
index 530e381..dd08fe2 100644
--- a/mergify_cli/ci/scopes/cli.py
+++ b/mergify_cli/ci/scopes/cli.py
@@ -10,7 +10,6 @@
 import pydantic
 
 from mergify_cli import utils
-from mergify_cli.ci.git_refs import detector as git_refs_detector
 from mergify_cli.ci.scopes import changed_files
 from mergify_cli.ci.scopes import config
 from mergify_cli.ci.scopes import exceptions
@@ -100,8 +99,6 @@ class InvalidDetectedScopeError(exceptions.ScopesError):
 
 
 class DetectedScope(pydantic.BaseModel):
-    base_ref: str
-    head_ref: str
     scopes: set[str]
 
     def save_to_file(self, file: str) -> None:
@@ -117,12 +114,17 @@ def load_from_file(cls, filename: str) -> DetectedScope:
                 raise InvalidDetectedScopeError(str(e))
 
 
-def detect(config_path: str) -> DetectedScope:
+def detect(
+    config_path: str,
+    *,
+    base: str,
+    head: str,
+    is_merge_queue: bool,
+) -> DetectedScope:
     cfg = config.Config.from_yaml(config_path)
-    git_refs = git_refs_detector.detect()
 
-    click.echo(f"Base: {git_refs.base}")
-    click.echo(f"Head: {git_refs.head}")
+    click.echo(f"Base: {base}")
+    click.echo(f"Head: {head}")
 
     scopes_hit: set[str]
     per_scope: dict[str, list[str]]
@@ -133,7 +135,7 @@ def detect(config_path: str) -> DetectedScope:
         scopes_hit = set()
         per_scope = {}
     elif isinstance(source, config.SourceFiles):
-        changed = changed_files.git_changed_files(git_refs.base, git_refs.head)
+        changed = changed_files.git_changed_files(base, head)
         click.echo("Changed files detected:")
         for file in changed:
             click.echo(f"- {file}")
@@ -148,7 +150,7 @@ def detect(config_path: str) -> DetectedScope:
 
     if cfg.scopes.merge_queue_scope is not None:
         all_scopes.add(cfg.scopes.merge_queue_scope)
-        if git_refs.is_merge_queue:
+        if is_merge_queue:
             scopes_hit.add(cfg.scopes.merge_queue_scope)
 
     if scopes_hit:
@@ -161,19 +163,14 @@ def detect(config_path: str) -> DetectedScope:
     else:
         click.echo("No scopes matched.")
 
-    git_refs.maybe_write_to_github_outputs()
     maybe_write_github_outputs(all_scopes, scopes_hit)
     maybe_write_github_step_summary(
-        git_refs.base,
-        git_refs.head,
+        base,
+        head,
         all_scopes,
         scopes_hit,
     )
-    return DetectedScope(
-        base_ref=git_refs.base,
-        head_ref=git_refs.head,
-        scopes=scopes_hit,
-    )
+    return DetectedScope(scopes=scopes_hit)
 
 
 async def send_scopes(
diff --git a/mergify_cli/tests/ci/scopes/test_cli.py b/mergify_cli/tests/ci/scopes/test_cli.py
index b4002a6..ccae011 100644
--- a/mergify_cli/tests/ci/scopes/test_cli.py
+++ b/mergify_cli/tests/ci/scopes/test_cli.py
@@ -8,7 +8,6 @@
 import respx
 import yaml
 
-from mergify_cli.ci.git_refs import detector
 from mergify_cli.ci.scopes import cli
 from mergify_cli.ci.scopes import config
 from mergify_cli.ci.scopes import exceptions
@@ -337,13 +336,11 @@ def test_maybe_write_github_outputs_no_env(
     cli.maybe_write_github_outputs(["backend"], {"backend"})
 
 
-@mock.patch("mergify_cli.ci.git_refs.detector.detect")
 @mock.patch("mergify_cli.ci.scopes.changed_files.git_changed_files")
 @mock.patch("mergify_cli.ci.scopes.cli.maybe_write_github_outputs")
 def test_detect_with_matches(
     mock_github_outputs: mock.Mock,
     mock_git_changed: mock.Mock,
-    mock_detect_base: mock.Mock,
     tmp_path: pathlib.Path,
 ) -> None:
     # Setup config file
@@ -361,19 +358,18 @@ def test_detect_with_matches(
     config_file.write_text(yaml.dump(config_data))
 
     # Setup mocks
-    mock_detect_base.return_value = detector.References(
-        "old",
-        "new",
-        is_merge_queue=True,
-    )
     mock_git_changed.return_value = ["api/models.py", "other.txt"]
 
     # Capture output
     with mock.patch("click.echo") as mock_echo:
-        result = cli.detect(str(config_file))
+        result = cli.detect(
+            str(config_file),
+            base="old",
+            head="new",
+            is_merge_queue=True,
+        )
 
     # Verify calls
-    mock_detect_base.assert_called_once()
     mock_git_changed.assert_called_once_with("old", "new")
     mock_github_outputs.assert_called_once()
 
@@ -385,16 +381,12 @@ def test_detect_with_matches(
     assert "- backend" in calls
     assert "- merge-queue" in calls
 
-    assert result.base_ref == "old"
-    assert result.head_ref == "new"
     assert result.scopes == {"backend", "merge-queue"}
 
 
-@mock.patch("mergify_cli.ci.git_refs.detector.detect")
 @mock.patch("mergify_cli.ci.scopes.cli.maybe_write_github_outputs")
 def test_detect_manual(
     _: mock.Mock,
-    mock_detect_base: mock.Mock,
     tmp_path: pathlib.Path,
 ) -> None:
     # Setup config file
@@ -404,28 +396,24 @@ def test_detect_manual(
     config_file = tmp_path / ".mergify-ci.yml"
     config_file.write_text(yaml.dump(config_data))
 
-    # Setup mocks
-    mock_detect_base.return_value = detector.References(
-        "old",
-        "new",
-        is_merge_queue=False,
-    )
-
     # Capture output
     with pytest.raises(
         exceptions.ScopesError,
         match="source `manual` has been set, scopes must be sent with `scopes-send` or API",
     ):
-        cli.detect(str(config_file))
+        cli.detect(
+            str(config_file),
+            base="old",
+            head="new",
+            is_merge_queue=False,
+        )
 
 
-@mock.patch("mergify_cli.ci.git_refs.detector.detect")
 @mock.patch("mergify_cli.ci.scopes.changed_files.git_changed_files")
 @mock.patch("mergify_cli.ci.scopes.cli.maybe_write_github_outputs")
 def test_detect_no_matches(
     _: mock.Mock,
     mock_git_changed: mock.Mock,
-    mock_detect_base: mock.Mock,
     tmp_path: pathlib.Path,
 ) -> None:
     # Setup config file
@@ -436,16 +424,16 @@ def test_detect_no_matches(
     config_file.write_text(yaml.dump(config_data))
 
     # Setup mocks
-    mock_detect_base.return_value = detector.References(
-        "old",
-        "new",
-        is_merge_queue=False,
-    )
     mock_git_changed.return_value = ["other.txt"]
 
     # Capture output
     with mock.patch("click.echo") as mock_echo:
-        result = cli.detect(str(config_file))
+        result = cli.detect(
+            str(config_file),
+            base="old",
+            head="new",
+            is_merge_queue=False,
+        )
 
     # Verify output
     calls = [call.args[0] for call in mock_echo.call_args_list]
@@ -453,15 +441,11 @@ def test_detect_no_matches(
     assert "Head: new" in calls
     assert "No scopes matched." in calls
     assert result.scopes == set()
-    assert result.base_ref == "old"
-    assert result.head_ref == "new"
 
 
-@mock.patch("mergify_cli.ci.git_refs.detector.detect")
 @mock.patch("mergify_cli.ci.scopes.changed_files.git_changed_files")
 def test_detect_debug_output(
     mock_git_changed: mock.Mock,
-    mock_detect_base: mock.Mock,
     tmp_path: pathlib.Path,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -476,23 +460,21 @@ def test_detect_debug_output(
     config_file.write_text(yaml.dump(config_data))
 
     # Setup mocks
-    mock_detect_base.return_value = detector.References(
-        "main",
-        "HEAD",
-        is_merge_queue=False,
-    )
     mock_git_changed.return_value = ["api/models.py", "api/views.py"]
 
     # Capture output
     with mock.patch("click.echo") as mock_echo:
-        result = cli.detect(str(config_file))
-
+        result = cli.detect(
+            str(config_file),
+            base="old",
+            head="new",
+            is_merge_queue=False,
+        )
     # Verify debug output includes file details
     calls = [call.args[0] for call in mock_echo.call_args_list]
     assert any("    api/models.py" in call for call in calls)
     assert any("    api/views.py" in call for call in calls)
 
-    assert result.base_ref == "main"
     assert result.scopes == {"backend"}
 
 
@@ -535,12 +517,9 @@ async def test_upload_scopes(respx_mock: respx.MockRouter) -> None:
 def test_dump(tmp_path: pathlib.Path) -> None:
     config_file = tmp_path / "scopes.json"
     saved = cli.DetectedScope(
-        base_ref="base",
-        head_ref="head",
         scopes={"backend", "merge-queue"},
     )
     saved.save_to_file(str(config_file))
 
     loaded = cli.DetectedScope.load_from_file(str(config_file))
     assert loaded.scopes == saved.scopes
-    assert loaded.base_ref == saved.base_ref