diff --git a/pkgs/clan-cli/clan_cli/dirs.py b/pkgs/clan-cli/clan_cli/dirs.py
index e895df0..514bbe1 100644
--- a/pkgs/clan-cli/clan_cli/dirs.py
+++ b/pkgs/clan-cli/clan_cli/dirs.py
@@ -2,18 +2,19 @@ import os
 import sys
 from pathlib import Path
 
+from .errors import ClanError
+
 
 def get_clan_flake_toplevel() -> Path:
     """Returns the path to the toplevel of the clan flake"""
-    initial_path = Path(os.getcwd())
-    path = Path(initial_path)
-    while path.parent == path:
-        project_files = [".clan-flake"]
-        for project_file in project_files:
+    for project_file in [".clan-flake", ".git", ".hg", ".svn", "flake.nix"]:
+        initial_path = Path(os.getcwd())
+        path = Path(initial_path)
+        while path.parent == path:
             if (path / project_file).exists():
                 return path
-        path = path.parent
-    return initial_path
+            path = path.parent
+    raise ClanError("Could not find clan flake toplevel directory")
 
 
 def user_data_dir() -> Path:
diff --git a/pkgs/clan-cli/tests/conftest.py b/pkgs/clan-cli/tests/conftest.py
index b389b36..f9b5b00 100644
--- a/pkgs/clan-cli/tests/conftest.py
+++ b/pkgs/clan-cli/tests/conftest.py
@@ -1,2 +1,6 @@
 import os
-sys.path.append(os.path.join(os.path.dirname(__file__), 'helpers'))
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), "helpers"))
+
+pytest_plugins = ["temporary_dir"]
diff --git a/pkgs/clan-cli/tests/temporary_dir.py b/pkgs/clan-cli/tests/temporary_dir.py
new file mode 100644
index 0000000..91310f9
--- /dev/null
+++ b/pkgs/clan-cli/tests/temporary_dir.py
@@ -0,0 +1,11 @@
+import tempfile
+from pathlib import Path
+from typing import Iterator
+
+import pytest
+
+
+@pytest.fixture
+def temporary_dir() -> Iterator[Path]:
+    with tempfile.TemporaryDirectory(prefix="pytest-") as dirpath:
+        yield Path(dirpath)
diff --git a/pkgs/clan-cli/tests/test_dirs.py b/pkgs/clan-cli/tests/test_dirs.py
new file mode 100644
index 0000000..e379490
--- /dev/null
+++ b/pkgs/clan-cli/tests/test_dirs.py
@@ -0,0 +1,14 @@
+from pathlib import Path
+
+import pytest
+
+from clan_cli.dirs import get_clan_flake_toplevel
+from clan_cli.errors import ClanError
+
+
+def test_get_clan_flake_toplevel(
+    monkeypatch: pytest.MonkeyPatch, temporary_dir: Path
+) -> None:
+    monkeypatch.chdir(temporary_dir)
+    with pytest.raises(ClanError):
+        get_clan_flake_toplevel()