diff --git a/src/teilchensammler_cli/models.py b/src/teilchensammler_cli/models.py
index 4ed6afc..7d01b4a 100644
--- a/src/teilchensammler_cli/models.py
+++ b/src/teilchensammler_cli/models.py
@@ -82,7 +82,14 @@ async def make_teilchen_input(text: str) -> TeilchenCreate | None:
 
 
 async def load_initial_data(engine) -> Sequence[Teilchen]:
+    """Retrieve all Teilchen records from the database.
 
+    Args:
+        engine (sqlalchemy.Engine): the engine or connection or whatever
+
+    Returns:
+        List of Teilchen, potentially empty
+    """
     with Session(engine) as session:
         statement = select(
             Teilchen.id, Teilchen.name, Teilchen.description, Teilchen.number, Teilchen.tags
@@ -92,6 +99,15 @@ async def load_initial_data(engine) -> Sequence[Teilchen]:
 
 
 async def add_to_database(tc: TeilchenCreate, engine) -> Teilchen:
+    """Add given data as a new record into the database.
+
+    Args:
+        engine (sqlalchemy.Engine): the engine or connection or whatever
+        tc: Teilchen data (no `id` yet)
+
+    Returns:
+        The newly created Teilchen (this time with `id`)
+    """
     with Session(engine) as session:
         teilchen = Teilchen.model_validate(tc)
         session.add(teilchen)