diff --git a/tests/local_testing/conftest.py b/tests/local_testing/conftest.py
index 6a746041f15..401a1fb85ec 100644
--- a/tests/local_testing/conftest.py
+++ b/tests/local_testing/conftest.py
@@ -22,6 +22,20 @@ sys.path.insert(
 )  # Adds the parent directory to the system path
 import litellm
 
+# ``litellm.model_cost`` is loaded at import time from the URL pinned to ``main``
+# (``LITELLM_MODEL_COST_MAP_URL``).  The in-tree backup ships with this branch
+# and can include pricing entries that ``main`` has not yet picked up (e.g.
+# Mistral now returns ``ministral-8b-2512`` from ``mistral-tiny`` and the entry
+# was added on this branch).  Backfill any entries that are missing from the
+# remote-fetched map so cost-calculator lookups in tests succeed against the
+# cassette state the branch is being tested with.
+from litellm.litellm_core_utils.get_model_cost_map import GetModelCostMap
+
+_local_cost_map = GetModelCostMap.load_local_model_cost_map()
+for _k, _v in _local_cost_map.items():
+    litellm.model_cost.setdefault(_k, _v)
+del _local_cost_map
+
 from tests._vcr_conftest_common import (  # noqa: E402,F401
     VerboseReporterState,
     _pin_multipart_boundary,