diff --git a/skore/src/skore/project/project.py b/skore/src/skore/project/project.py
index 289b04d10..b2ae7fcbc 100644
--- a/skore/src/skore/project/project.py
+++ b/skore/src/skore/project/project.py
@@ -1,7 +1,7 @@
 """Define a Project."""
 
 import logging
-from typing import Any, Optional, Union
+from typing import Any
 
 from skore.item import (
     CrossValidationItem,
@@ -25,9 +25,6 @@
 logger.setLevel(logging.INFO)
 
 
-MISSING = object()
-
-
 class Project:
     """
     A collection of items arranged in views and stored in a storage.
@@ -80,44 +77,18 @@ def __init__(
         self.item_repository = item_repository
         self.view_repository = view_repository
 
-    def put(self, key: Union[str, dict[str, Any]], value: Optional[Any] = MISSING):
-        """Add one or more key-value pairs to the Project.
+    def put(self, key: str, value: Any):
+        """Add a key-value pair to the Project.
 
         If an item with the same key already exists, its value is replaced by the new
         one.
 
-        If ``key`` is a string, then :func:`~skore.Project.put` adds the single
-        ``key``-``value`` pair mapping to the Project.
-        If ``key`` is a dict, it is interpreted as multiple key-value pairs to add to
-        the Project.
-
-        The dict format is equivalent to running :func:`~skore.Project.put`
-        for each individual key-value pair. In other words,
-
-        .. code-block:: python
-
-            project.put({"hello": 1, "goodbye": 2})
-
-        is equivalent to
-
-        .. code-block:: python
-
-            project.put("hello", 1)
-            project.put("goodbye", 2)
-
-        In particular, this means that if some key-value pair is invalid
-        (e.g. if a key is not a string, or a value's type is not supported),
-        then all the key-value pairs up to the first offending key-value pair will
-        be successfully inserted, *and then* an error will be raised.
-
         Parameters
         ----------
-        key : str | dict[str, Any]
-            The key to associate with ``value`` in the Project,
-            or dict of key-value pairs to add to the Project.
-        value : Any, optional
+        key : str
+            The key to associate with ``value`` in the Project.
+        value : Any
             The value to associate with ``key`` in the Project.
-            If ``key`` is a dict, this argument is ignored.
 
         Raises
         ------
@@ -127,21 +98,10 @@ def put(self, key: Union[str, dict[str, Any]], value: Optional[Any] = MISSING):
         NotImplementedError
             If the value type is not supported.
         """
-        if value is not MISSING:
-            key_to_item = {key: value}
-        elif isinstance(key, dict):
-            key_to_item = key
-        else:
-            raise TypeError(
-                f"Bad parameters. "
-                f"When value is not specified, key must be a dict (found '{type(key)}')"
-            )
-
-        for key, value in key_to_item.items():
-            if not isinstance(key, str):
-                raise TypeError(f"Key must be a string (found '{type(key)}')")
+        if not isinstance(key, str):
+            raise TypeError(f"Key must be a string (found '{type(key)}')")
 
-            self.item_repository.put_item(key, object_to_item(value))
+        self.item_repository.put_item(key, object_to_item(value))
 
     def put_item(self, key: str, item: Item):
         """Add an Item to the Project."""
diff --git a/skore/tests/unit/project/test_project.py b/skore/tests/unit/project/test_project.py
index 85cd8dbf0..866db9cf9 100644
--- a/skore/tests/unit/project/test_project.py
+++ b/skore/tests/unit/project/test_project.py
@@ -218,36 +218,6 @@ def test_list_view_keys(in_memory_project):
     assert in_memory_project.list_view_keys() == ["view"]
 
 
-def test_put_several_happy_path(in_memory_project):
-    in_memory_project.put({"a": "foo", "b": "bar"})
-    assert in_memory_project.list_item_keys() == ["a", "b"]
-
-
-def test_put_several_some_errors(in_memory_project):
-    with pytest.raises(TypeError):
-        in_memory_project.put({0: "hello", 1: "hello", 2: "hello"})
-    assert in_memory_project.list_item_keys() == []
-
-
-def test_put_several_nested(in_memory_project):
-    in_memory_project.put({"a": {"b": "baz"}})
-    assert in_memory_project.list_item_keys() == ["a"]
-    assert in_memory_project.get("a") == {"b": "baz"}
-
-
-def test_put_several_error(in_memory_project):
-    """If some key-value pairs are wrong, add all that are valid and print a warning."""
-    with pytest.raises(NotImplementedError):
-        in_memory_project.put(
-            {
-                "a": "foo",
-                "b": (lambda: "unsupported object"),
-            }
-        )
-
-    assert in_memory_project.list_item_keys() == ["a"]
-
-
 def test_put_key_is_a_tuple(in_memory_project):
     """If key is not a string, warn."""
     with pytest.raises(TypeError):