diff --git a/renku/command/command_builder/command.py b/renku/command/command_builder/command.py
index bcf973bdfe..bb4c1e00f2 100644
--- a/renku/command/command_builder/command.py
+++ b/renku/command/command_builder/command.py
@@ -21,7 +21,8 @@
 import functools
 import threading
 from collections import defaultdict
-from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional
+from pathlib import Path
+from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Union
 
 import click
 import inject
@@ -433,7 +434,7 @@ def with_commit(
         message: Optional[str] = None,
         commit_if_empty: bool = False,
         raise_if_empty: bool = False,
-        commit_only: Optional[bool] = None,
+        commit_only: Optional[Union[str, List[Union[str, Path]]]] = None,
         skip_staging: bool = False,
     ) -> "Command":
         """Create a commit.
diff --git a/renku/command/command_builder/repo.py b/renku/command/command_builder/repo.py
index 11141d82cb..815becf6b2 100644
--- a/renku/command/command_builder/repo.py
+++ b/renku/command/command_builder/repo.py
@@ -17,7 +17,8 @@
 # limitations under the License.
 """Command builder for repository."""
 
-from typing import Optional
+from pathlib import Path
+from typing import List, Optional, Union
 
 from renku.command.command_builder.command import Command, CommandResult, check_finalized
 from renku.core import errors
@@ -34,7 +35,7 @@ def __init__(
         message: Optional[str] = None,
         commit_if_empty: Optional[bool] = False,
         raise_if_empty: Optional[bool] = False,
-        commit_only: Optional[bool] = None,
+        commit_only: Optional[Union[str, List[Union[str, Path]]]] = None,
         skip_staging: bool = False,
     ) -> None:
         """__init__ of Commit.
diff --git a/renku/ui/cli/mergetool.py b/renku/ui/cli/mergetool.py
index 28e19a8103..0ebf4b6a7d 100644
--- a/renku/ui/cli/mergetool.py
+++ b/renku/ui/cli/mergetool.py
@@ -58,4 +58,4 @@ def install():
     """Setup mergetool locally."""
     from renku.command.mergetool import mergetool_install_command
 
-    mergetool_install_command().with_commit().build().execute()
+    mergetool_install_command().with_commit(commit_only=[".gitattributes"]).require_clean().build().execute()