From be8acac33fd5653aaaac2dfe426ef0c472e6c731 Mon Sep 17 00:00:00 2001
From: VectorPeak <167914171+VectorPeak@users.noreply.github.com>
Date: Wed, 24 Jun 2026 10:58:13 +0800
Subject: [PATCH] fix(cohere): normalize rerank v2 api base

---
 .../llms/cohere/rerank_v2/transformation.py   |  5 +++--
 .../rerank/test_rerank_v2_transformation.py   | 20 +++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 tests/test_litellm/llms/cohere/rerank/test_rerank_v2_transformation.py

diff --git a/litellm/llms/cohere/rerank_v2/transformation.py b/litellm/llms/cohere/rerank_v2/transformation.py
index 4c800d6455d..494f5e6fc8f 100644
--- a/litellm/llms/cohere/rerank_v2/transformation.py
+++ b/litellm/llms/cohere/rerank_v2/transformation.py
@@ -19,9 +19,10 @@ class CohereRerankV2Config(CohereRerankConfig):
         optional_params: Optional[dict] = None,
     ) -> str:
         if api_base:
-            # Remove trailing slashes and ensure clean base URL
             api_base = api_base.rstrip("/")
-            if not api_base.endswith("/v2/rerank"):
+            if api_base.endswith("/v2"):
+                api_base = f"{api_base}/rerank"
+            elif not api_base.endswith("/v2/rerank"):
                 api_base = f"{api_base}/v2/rerank"
             return api_base
         return "https://api.cohere.ai/v2/rerank"
diff --git a/tests/test_litellm/llms/cohere/rerank/test_rerank_v2_transformation.py b/tests/test_litellm/llms/cohere/rerank/test_rerank_v2_transformation.py
new file mode 100644
index 00000000000..4caf1354078
--- /dev/null
+++ b/tests/test_litellm/llms/cohere/rerank/test_rerank_v2_transformation.py
@@ -0,0 +1,20 @@
+import pytest
+
+from litellm.llms.cohere.rerank_v2.transformation import CohereRerankV2Config
+
+
+@pytest.mark.parametrize(
+    ("api_base", "expected_url"),
+    [
+        ("https://api.cohere.ai", "https://api.cohere.ai/v2/rerank"),
+        ("https://api.cohere.ai/v2", "https://api.cohere.ai/v2/rerank"),
+        ("https://api.cohere.ai/v2/rerank/", "https://api.cohere.ai/v2/rerank"),
+    ],
+)
+def test_get_complete_url_normalizes_cohere_rerank_v2_api_base(
+    api_base: str, expected_url: str
+) -> None:
+    assert (
+        CohereRerankV2Config().get_complete_url(api_base=api_base, model="rerank-v3.5")
+        == expected_url
+    )