diff --git a/src/app_model/_types.py b/src/app_model/_types.py
index 97b293d..aede66d 100644
--- a/src/app_model/_types.py
+++ b/src/app_model/_types.py
@@ -57,7 +57,12 @@ class KeybindingRuleDict(TypedDict, total=False):
 # ------------------ commands-related types --------------------
 
 
-class Icon(BaseModel):
+class _StrictModel(BaseModel):
+    class Config:
+        extra = "forbid"
+
+
+class Icon(_StrictModel):
     """Icons used to represent commands, or submenus.
 
     May provide both a light and dark variant.  If only one is provided, it is used
@@ -87,7 +92,7 @@ def validate(cls, v: Any) -> Icon:
         return cls(**v)
 
 
-class CommandRule(BaseModel):
+class CommandRule(_StrictModel):
     """Data representing a command and its presentation.
 
     Presentation of contributed commands depends on the containing menu. The Command
@@ -132,7 +137,7 @@ class CommandRule(BaseModel):
 # ------------------ keybinding-related types --------------------
 
 
-class KeybindingRule(BaseModel):
+class KeybindingRule(_StrictModel):
     """Data representing a keybinding and when it should be active.
 
     This model lacks a corresponding command. That gets linked up elsewhere,
@@ -174,7 +179,7 @@ def _bind_to_current_platform(self) -> Optional[KeyCodeStr]:
 # ------------------ menus-related types --------------------
 
 
-class _MenuItemBase(BaseModel):
+class _MenuItemBase(_StrictModel):
     """Data representing where and when a menu item should be shown."""
 
     when: Optional[context.Expr] = Field(
diff --git a/tests/test_actions.py b/tests/test_actions.py
index 6682572..459f065 100644
--- a/tests/test_actions.py
+++ b/tests/test_actions.py
@@ -23,7 +23,7 @@
     dict(keybindings=[{"primary": PRIMARY_KEY}]),
     dict(
         keybindings=[
-            {"primary": PRIMARY_KEY, "mac": OS_KEY, "windows": OS_KEY, "linux": OS_KEY}
+            {"primary": PRIMARY_KEY, "mac": OS_KEY, "win": OS_KEY, "linux": OS_KEY}
         ]
     ),
     dict(keybindings=[{"primary": "ctrl+a"}], menus=[{"id": MENUID}]),
diff --git a/tests/test_id.py b/tests/test_id.py
new file mode 100644
index 0000000..4e8cb70
--- /dev/null
+++ b/tests/test_id.py
@@ -0,0 +1,10 @@
+import os
+import platform
+import sys
+
+
+def test_plat():
+    print(f"{os.name=}")
+    print(f"{sys.platform=}")
+    print(f"{platform.system()=}")
+    print(f"{platform.release()=}")
diff --git a/tox.ini b/tox.ini
index 482d968..449e6ef 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,4 +26,4 @@ setenv =
 extras =
     test
 commands =
-    pytest -v --cov=app_model --cov-report=xml --color=yes --basetemp={envtmpdir} {posargs}
+    pytest -v -s --cov=app_model --cov-report=xml --color=yes --basetemp={envtmpdir} {posargs}