diff --git a/docs/conf.py b/docs/conf.py
index b0c0214..4157705 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -68,7 +68,7 @@
 # You can specify multiple suffix as a list of string:
 #
 # source_suffix = ['.rst', '.md']
-source_suffix = ".rst"
+source_suffix = {".rst": "restructuredtext"}
 
 # The master toctree document.
 master_doc = "index"
@@ -170,8 +170,8 @@
 # Example configuration for intersphinx: refer to the Python standard library.
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3/", None),
-    "requests": ("https://docs.python-requests.org/en/master/", None),
-    "urllib3": ("https://urllib3.readthedocs.io/en/latest/", None),
+    "requests": ("https://docs.python-requests.org/en/latest", None),
+    "urllib3": ("https://urllib3.readthedocs.io/en/latest", None),
 }
 
 # -- Options for todo extension ----------------------------------------------
diff --git a/pyproject.toml b/pyproject.toml
index 9b446a2..6dbd511 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -132,7 +132,7 @@ commands = [
 [tool.tox.env.typecheck]
 deps = [
     { replace = "ref", of = ["tool", "tox", "env_run_base", "deps"], extend = true },
-    "mypy",
+    "mypy<1.12.0",  # https://github.com/python/mypy/issues/17960
     "typing_extensions",
     "types-requests",
     "types-urllib3",
diff --git a/src/apiron/service/base.py b/src/apiron/service/base.py
index a438b03..344e523 100644
--- a/src/apiron/service/base.py
+++ b/src/apiron/service/base.py
@@ -61,7 +61,7 @@ def get_hosts(cls) -> list[str]:
         return [cls.domain]
 
     def __str__(self) -> str:
-        return self.__class__.domain
+        return getattr(self.__class__, "domain", "UNKNOWN")
 
     def __repr__(self) -> str:
         return f"{self.__class__.__name__}(domain={self.__class__.domain})"