From 5ea447e295109b4079d1b41a70f82f1d88024e6a Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Tue, 8 Sep 2026 17:19:23 -0700
Subject: [PATCH] fix(azure): keep the model group segment exact and casefold
 only deployment names in the relay guard

---
 litellm/llms/azure/passthrough/transformation.py             | 5 ++---
 .../passthrough/test_azure_passthrough_transformation.py     | 4 ++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/litellm/llms/azure/passthrough/transformation.py b/litellm/llms/azure/passthrough/transformation.py
index 69767bb29a3..1b5a4083ebe 100644
--- a/litellm/llms/azure/passthrough/transformation.py
+++ b/litellm/llms/azure/passthrough/transformation.py
@@ -82,11 +82,10 @@ def foreign_azure_deployment(
     if match is None:
         return None
     deployment: Final = match.group(1)
-    folded: Final = deployment.casefold()
-    if folded == model_group.casefold():
+    if deployment == model_group:
         return None
     served: Final = frozenset(name.casefold() for name in served_models())
-    return None if folded in served else deployment
+    return None if deployment.casefold() in served else deployment
 
 
 def without_api_version(api_base: str) -> str:
diff --git a/tests/test_litellm/llms/azure/passthrough/test_azure_passthrough_transformation.py b/tests/test_litellm/llms/azure/passthrough/test_azure_passthrough_transformation.py
index 798ef1f5a4f..c7e86616ee2 100644
--- a/tests/test_litellm/llms/azure/passthrough/test_azure_passthrough_transformation.py
+++ b/tests/test_litellm/llms/azure/passthrough/test_azure_passthrough_transformation.py
@@ -457,7 +457,7 @@ def test_azure_passthrough_is_streaming_request_reads_the_stream_flag(request_da
         ("openai/deployments/gpt/chat/completions", None),
         ("gpt/openai/deployments/gpt-5.4-mini/chat/completions", None),
         ("gpt/openai/deployments/GPT-5.4-MINI/chat/completions", None),
-        ("gpt/openai/deployments/Gpt/chat/completions", None),
+        ("gpt/openai/deployments/Gpt/chat/completions", "Gpt"),
         ("gpt/models/chat/completions", None),
         ("gpt/openai/deployments/gpt-5.4/chat/completions", "gpt-5.4"),
         ("gpt/openai/deployments/other-group/chat/completions", "other-group"),
@@ -473,7 +473,7 @@ def test_foreign_azure_deployment_skips_the_router_when_the_segment_is_the_group
     def served_models():
         raise AssertionError("the router must not be consulted for the group's own name")
 
-    assert foreign_azure_deployment("gpt/openai/deployments/Gpt/chat/completions", "gpt", served_models) is None
+    assert foreign_azure_deployment("gpt/openai/deployments/gpt/chat/completions", "gpt", served_models) is None
 
 
 @pytest.mark.parametrize(