diff --git a/mergify_cli/ci/scopes/config/scopes.py b/mergify_cli/ci/scopes/config/scopes.py
index 3e171b4..b784783 100644
--- a/mergify_cli/ci/scopes/config/scopes.py
+++ b/mergify_cli/ci/scopes/config/scopes.py
@@ -15,6 +15,8 @@
 
 
 class FileFilters(pydantic.BaseModel):
+    model_config = pydantic.ConfigDict(extra="forbid")
+
     include: tuple[str, ...] = pydantic.Field(
         default_factory=lambda: ("**/*",),
         description=(
@@ -34,6 +36,8 @@ class FileFilters(pydantic.BaseModel):
 
 
 class SourceFiles(pydantic.BaseModel):
+    model_config = pydantic.ConfigDict(extra="forbid")
+
     files: dict[ScopeName, FileFilters] = pydantic.Field(
         description=(
             "Mapping of scope name to its file filters. "
@@ -44,6 +48,8 @@ class SourceFiles(pydantic.BaseModel):
 
 
 class SourceManual(pydantic.BaseModel):
+    model_config = pydantic.ConfigDict(extra="forbid")
+
     manual: None = pydantic.Field(
         description="Scopes are manually sent via API or `mergify scopes-send`",
     )
diff --git a/mergify_cli/tests/ci/scopes/test_cli.py b/mergify_cli/tests/ci/scopes/test_cli.py
index 4bf0a89..1ad1e0a 100644
--- a/mergify_cli/tests/ci/scopes/test_cli.py
+++ b/mergify_cli/tests/ci/scopes/test_cli.py
@@ -106,7 +106,7 @@ def test_from_yaml_invalid_config(tmp_path: pathlib.Path) -> None:
     )
 
     # Bad name and missing dict
-    with pytest.raises(config.ConfigInvalidError, match="3 validation errors"):
+    with pytest.raises(config.ConfigInvalidError, match="4 validation errors"):
         config.Config.from_yaml(str(config_file))
 
 
@@ -481,6 +481,22 @@ def test_detect_no_matches(
     assert result.scopes == set()
 
 
+def test_match_scopes_invalid() -> None:
+    with pytest.raises(config.ConfigInvalidError, match="4 validation errors"):
+        config.Config.from_dict(
+            {
+                "scopes": {
+                    "source": {
+                        "files": {
+                            "backend": {"includes": ("api/**/*.py",)},
+                            "frontend": {"includes": ("ui/**/*.js",)},
+                        },
+                    },
+                },
+            },
+        )
+
+
 @mock.patch("mergify_cli.ci.scopes.changed_files.git_changed_files")
 def test_detect_debug_output(
     mock_git_changed: mock.Mock,