From 512157f63cc6fcd07771cf41d342048803c88588 Mon Sep 17 00:00:00 2001
From: Joshua Valluru <326636767+joshua-berri@users.noreply.github.com>
Date: Mon, 19 Oct 2026 15:49:10 -0700
Subject: [PATCH] fix(pricing): retain registered rates across metadata updates

---
 litellm/utils.py                   |  5 ++++-
 tests/unit/test_cost_calculator.py | 10 ++++++++++
 tests/unit/test_utils.py           | 18 +++++++++++++++---
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/litellm/utils.py b/litellm/utils.py
index 6281be334df..e45faeaf6b1 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -3740,7 +3740,10 @@ def register_model(
     if persist_across_reloads:
         _registrations: Final[Mapping[str, Mapping[str, object]]] = loaded_model_cost
         for _registered_key, _registered_value in _registrations.items():
-            _runtime_registered_model_cost[_registered_key] = dict(_registered_value)
+            _runtime_registered_model_cost[_registered_key] = update_dictionary(
+                dict(_runtime_registered_model_cost.get(_registered_key, {})),
+                _RATE_TABLE.validate_python(_registered_value),
+            )
 
     for key, value in loaded_model_cost.items():
         write = _register_on_current_map(str(key), value, custom_llm_provider, warning_display_name)
diff --git a/tests/unit/test_cost_calculator.py b/tests/unit/test_cost_calculator.py
index c0cdc246c0d..957a7e951eb 100644
--- a/tests/unit/test_cost_calculator.py
+++ b/tests/unit/test_cost_calculator.py
@@ -9856,6 +9856,7 @@ def test_bedrock_converse_profile_preserves_registered_price_override(
             }
         }
     )
+    litellm.register_model({model: {"supports_function_calling": True, "input_cost_per_token": None}})
     response: Final = ModelResponse(model=model, usage=Usage(prompt_tokens=10, completion_tokens=5, total_tokens=15))
 
     assert completion_cost(
@@ -9865,6 +9866,15 @@ def test_bedrock_converse_profile_preserves_registered_price_override(
         optional_params={"model_id": f"us.{model}"},
     ) == pytest.approx(15 * rate)
 
+    updated_rate: Final = rate + 0.002
+    litellm.register_model({model: {"input_cost_per_token": str(updated_rate)}})
+    assert completion_cost(
+        completion_response=response,
+        model=f"bedrock/converse/{model}",
+        custom_llm_provider="bedrock",
+        optional_params={"model_id": f"us.{model}"},
+    ) == pytest.approx(10 * updated_rate + 5 * rate)
+
 
 def test_bedrock_converse_profile_ignores_registered_capabilities_without_prices(
     _local_model_cost_map: None, monkeypatch: pytest.MonkeyPatch
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index c491af9de18..7764d71a622 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -4806,7 +4806,11 @@ async def test_builtin_string_callback_registers_when_subclass_already_active(
 
 @pytest.mark.usefixtures("isolated_openai_model_sets")
 @pytest.mark.usefixtures("isolated_openai_model_sets")
-def test_reapply_runtime_registrations_replays_register_model_overrides(monkeypatch):
+@pytest.mark.parametrize("rate", (0.0, 0.000123))
+@pytest.mark.parametrize("updated_rate", (None, 0.0, 0.000456))
+def test_reapply_runtime_registrations_replays_register_model_overrides(
+    monkeypatch: pytest.MonkeyPatch, rate: float, updated_rate: float | None
+) -> None:
     """
     register_model is the documented way to override pricing for a model. A
     price-data reload swaps litellm.model_cost for a freshly fetched catalog,
@@ -4837,11 +4841,17 @@ def test_reapply_runtime_registrations_replays_register_model_overrides(monkeypa
                 "openai/gpt-4o": {
                     "litellm_provider": "openai",
                     "mode": "chat",
-                    "input_cost_per_token": 0.000123,
+                    "input_cost_per_token": rate,
                 }
             }
         )
 
+        litellm.register_model({"openai/gpt-4o": {"supports_function_calling": True, "input_cost_per_token": None}})
+        litellm.register_model(
+            {"openai/gpt-4o": {"input_cost_per_token": str(updated_rate) if updated_rate is not None else None}}
+        )
+        litellm.register_model({"openai/gpt-4o": {"supports_function_calling": False}})
+
         litellm.model_cost = {
             "openai/gpt-4o": {
                 "litellm_provider": "openai",
@@ -4853,7 +4863,9 @@ def test_reapply_runtime_registrations_replays_register_model_overrides(monkeypa
         _invalidate_model_cost_lowercase_map()
         reapply_runtime_model_cost_registrations()
 
-        assert litellm.model_cost["openai/gpt-4o"]["input_cost_per_token"] == 0.000123
+        expected_rate: Final = rate if updated_rate is None else updated_rate
+        assert litellm.model_cost["openai/gpt-4o"]["input_cost_per_token"] == expected_rate
+        assert litellm.model_cost["openai/gpt-4o"]["supports_function_calling"] is False
         assert litellm.model_cost["openai/gpt-4o"]["max_input_tokens"] == 4242
     finally:
         litellm.model_cost = saved_model_cost