From e734cc2d05cf8296ca75e24d1b91c6bdf3577d17 Mon Sep 17 00:00:00 2001
From: Genmin <joey@joeyroth.com>
Date: Fri, 1 May 2026 07:44:04 -0700
Subject: [PATCH] fix: avoid standalone system separator blocks

---
 litellm/llms/base_llm/base_utils.py           | 28 ++++++++++++++++++-
 .../test_base_llm_base_utils.py               | 25 +++++++++++++++--
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/litellm/llms/base_llm/base_utils.py b/litellm/llms/base_llm/base_utils.py
index d365c942dec..13c18b9ce5f 100644
--- a/litellm/llms/base_llm/base_utils.py
+++ b/litellm/llms/base_llm/base_utils.py
@@ -272,7 +272,33 @@ def _merge_system_message_contents(contents: List[Any]) -> Union[str, List[Any]]
             continue
 
         if merged_blocks:
-            merged_blocks.append({"type": "text", "text": "\n\n"})
+            last_block = merged_blocks[-1]
+            first_block = content_blocks[0]
+            if (
+                isinstance(last_block, dict)
+                and last_block.get("type") == "text"
+                and isinstance(last_block.get("text"), str)
+                and isinstance(first_block, dict)
+                and first_block.get("type") == "text"
+                and isinstance(first_block.get("text"), str)
+            ):
+                last_block["text"] += "\n\n" + first_block["text"]
+                merged_blocks.extend(content_blocks[1:])
+                continue
+            if (
+                isinstance(last_block, dict)
+                and last_block.get("type") == "text"
+                and isinstance(last_block.get("text"), str)
+            ):
+                last_block["text"] += "\n\n"
+            elif (
+                isinstance(first_block, dict)
+                and first_block.get("type") == "text"
+                and isinstance(first_block.get("text"), str)
+            ):
+                first_block = dict(first_block)
+                first_block["text"] = "\n\n" + first_block["text"]
+                content_blocks = [first_block, *content_blocks[1:]]
         merged_blocks.extend(content_blocks)
     return merged_blocks
 
diff --git a/tests/test_litellm/litellm_core_utils/test_base_llm_base_utils.py b/tests/test_litellm/litellm_core_utils/test_base_llm_base_utils.py
index 7ed50edc1af..6794443d0a3 100644
--- a/tests/test_litellm/litellm_core_utils/test_base_llm_base_utils.py
+++ b/tests/test_litellm/litellm_core_utils/test_base_llm_base_utils.py
@@ -51,9 +51,28 @@ def test_map_developer_role_preserves_structured_leading_system_content():
         {
             "role": "system",
             "content": [
-                {"type": "text", "text": "System rules."},
-                {"type": "text", "text": "\n\n"},
-                {"type": "text", "text": "Developer rules."},
+                {"type": "text", "text": "System rules.\n\nDeveloper rules."},
+            ],
+        },
+        {"role": "user", "content": "Hello!"},
+    ]
+
+
+def test_map_developer_role_avoids_standalone_separator_blocks():
+    messages = [
+        {"role": "system", "content": [{"type": "image", "url": "policy.png"}]},
+        {"role": "developer", "content": "Developer rules."},
+        {"role": "user", "content": "Hello!"},
+    ]
+
+    result = map_developer_role_to_system_role(messages=messages)
+
+    assert result == [
+        {
+            "role": "system",
+            "content": [
+                {"type": "image", "url": "policy.png"},
+                {"type": "text", "text": "\n\nDeveloper rules."},
             ],
         },
         {"role": "user", "content": "Hello!"},