diff --git a/mypy.ini b/mypy.ini
index 01cbb57a8..e6e7d16ff 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1,3 +1,10 @@
 [mypy]
 ignore_missing_imports = True
 plugins=mypy_zope:plugin
+show_column_numbers = True
+pretty = True
+show_error_codes = True
+warn_unused_configs =True
+no_implicit_optional = True
+warn_redundant_casts = True
+strict_equality = True
\ No newline at end of file
diff --git a/newsfragments/3971.minor b/newsfragments/3971.minor
new file mode 100644
index 000000000..a6cbb6a89
--- /dev/null
+++ b/newsfragments/3971.minor
@@ -0,0 +1 @@
+Changes made to mypy.ini to make mypy more 'strict' and prevent future regressions.
\ No newline at end of file
diff --git a/src/allmydata/web/common.py b/src/allmydata/web/common.py
index c49354217..3d85b1c4d 100644
--- a/src/allmydata/web/common.py
+++ b/src/allmydata/web/common.py
@@ -707,12 +707,12 @@ def url_for_string(req, url_string):
 T = TypeVar("T")
 
 @overload
-def get_arg(req: IRequest, argname: str | bytes, default: T = None, *, multiple: Literal[False] = False) -> T | bytes: ...
+def get_arg(req: IRequest, argname: str | bytes, default: Optional[T] = None, *, multiple: Literal[False] = False) -> T | bytes: ...
 
 @overload
-def get_arg(req: IRequest, argname: str | bytes, default: T = None, *, multiple: Literal[True]) -> T | tuple[bytes, ...]: ...
+def get_arg(req: IRequest, argname: str | bytes, default: Optional[T] = None, *, multiple: Literal[True]) -> T | tuple[bytes, ...]: ...
 
-def get_arg(req: IRequest, argname: str | bytes, default: T = None, *, multiple: bool = False) -> None | T | bytes | tuple[bytes, ...]:
+def get_arg(req: IRequest, argname: str | bytes, default: Optional[T] = None, *, multiple: bool = False) -> None | T | bytes | tuple[bytes, ...]:
     """Extract an argument from either the query args (req.args) or the form
     body fields (req.fields). If multiple=False, this returns a single value
     (or the default, which defaults to None), and the query args take