From 6251142e3868d67c9a8e00430e0ffec0b5a1ddfc Mon Sep 17 00:00:00 2001
From: TobiMayr <tobi.mayr@proton.me>
Date: Wed, 14 Oct 2026 12:58:50 +0100
Subject: [PATCH] fix(router): read rpm through a typed mapping so the skip
 stays type-clean

---
 litellm/router.py | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/litellm/router.py b/litellm/router.py
index d7a3e54fac0..c6dd4e2d08b 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -14022,6 +14022,16 @@ class Router:
             if param in _PRE_CALL_CHECK_FILTERED_PARAMS and not isinstance(value, str)
         )
 
+    def _deployment_configures_rpm(self, deployment: object) -> bool:
+        if not isinstance(deployment, dict):
+            return False
+        fields: Final[Mapping[str, object]] = cast(Mapping[str, object], deployment)  # cast-ok: untyped dict
+        params: Final = fields.get("litellm_params")
+        if not isinstance(params, dict):
+            return False
+        parsed_params: Final[Mapping[str, object]] = cast(Mapping[str, object], params)  # cast-ok: untyped dict
+        return parsed_params.get("rpm") is not None
+
     def _pre_call_checks(
         self,
         model: str,
@@ -14080,18 +14090,19 @@ class Router:
         # Safe to check statically since `rpm` is a direct litellm_params setting, unlike
         # max_input_tokens which get_router_model_info() can also derive from the cost map.
         any_deployment_has_rpm: Final = self.routing_strategy != "usage-based-routing-v2" and any(
-            isinstance(litellm_params := d.get("litellm_params"), dict) and litellm_params.get("rpm") is not None
-            for d in _returned_deployments
+            self._deployment_configures_rpm(
+                deployment  # pyright: ignore[reportUnknownArgumentType]  # untyped deployment list
+            )
+            for deployment in _returned_deployments  # pyright: ignore[reportUnknownVariableType]  # untyped list
         )
 
         ## get model group RPM ##
         rpm_key: Final = f"{model}:rpm:{get_utc_datetime().strftime('%H-%M')}"
-        cached_model_group: Final = (
-            self.cache.get_cache(key=rpm_key, local_only=True, parent_otel_span=parent_otel_span)
+        model_group_cache: Final = (
+            (self.cache.get_cache(key=rpm_key, local_only=True, parent_otel_span=parent_otel_span) or {})
             if any_deployment_has_rpm
-            else None
+            else {}
         )
-        model_group_cache: Final = cached_model_group if isinstance(cached_model_group, dict) else {}
         for idx, deployment in enumerate(_returned_deployments):
             # Cache nested dict access to avoid repeated temporary dict allocations
             _litellm_params = deployment.get("litellm_params", {})
@@ -14115,7 +14126,7 @@ class Router:
                 continue
 
             ## RPM CHECK ##
-            if any_deployment_has_rpm:
+            if any_deployment_has_rpm and isinstance(model_group_cache, dict):
                 model_id = _model_info.get("id", "")
                 ### get local router cache ###
                 current_request_cache_local = (