fix(proxy): restore model pricing in /v2/model/info after a request

A deployment that has served a request carries its cost keys as explicit
None, since Deployment normalises model_info through ModelInfo and
materialises every unset field. The enrichment pass backfilled only keys
that were absent, so a None never healed and the Costs column went blank
for exactly the models being used while untouched models kept their prices.
Cost tracking was never affected, only what this endpoint reported. Treat
None as unset when backfilling

Fixes #37637

litellm/proxy/proxy_server.py

@@ -12475,7 +12475,7 @@ def _enrich_model_info_with_litellm_data(
             except Exception:
                 litellm_model_info = {}
     for k, v in litellm_model_info.items():
-        if k not in model_info:
+        if model_info.get(k) is None:
             model_info[k] = v
     model["model_info"] = model_info
     # don't return the api key / vertex credentials

tests/test_litellm/proxy/proxy_server/test_routes_model_info.py

@@ -69,6 +69,31 @@ def test_v2_model_info_in_openapi_schema():
     assert "get" in schema["paths"]["/v2/model/info"]
 
 
+def test_v2_model_info_enrichment_heals_none_valued_cost_keys():
+    """A deployment that has served a request carries its cost keys as explicit None, because
+    Deployment materialises every unset ModelInfo field. Backfilling only absent keys left those
+    None values unhealed, so this route reported no pricing for exactly the models in use."""
+    from litellm.proxy.proxy_server import _enrich_model_info_with_litellm_data
+
+    base = {
+        "model_name": "claude-haiku-4-5",
+        "litellm_params": {"model": "anthropic/claude-haiku-4-5-20251001"},
+    }
+
+    absent = _enrich_model_info_with_litellm_data(model={**base, "model_info": {"id": "abc"}})
+    expected = absent["model_info"]["input_cost_per_token"]
+    assert expected is not None
+
+    served = _enrich_model_info_with_litellm_data(
+        model={
+            **base,
+            "model_info": {"id": "abc", "input_cost_per_token": None, "output_cost_per_token": None},
+        }
+    )
+    assert served["model_info"]["input_cost_per_token"] == expected
+    assert served["model_info"]["output_cost_per_token"] is not None
+
+
 # ---------------------------------------------------------------------------
 # GET /v1/model/info, GET /model/info
 # ---------------------------------------------------------------------------