diff --git a/src/pipecat/services/deepseek/llm.py b/src/pipecat/services/deepseek/llm.py
index cfb69cb9a..177a87e63 100644
--- a/src/pipecat/services/deepseek/llm.py
+++ b/src/pipecat/services/deepseek/llm.py
@@ -30,6 +30,10 @@ class DeepSeekLLMService(OpenAILLMService):
     maintaining full compatibility with OpenAI's interface and functionality.
     """
 
+    # DeepSeek doesn't support the "developer" message role.
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = DeepSeekLLMSettings
     _settings: Settings
 
diff --git a/src/pipecat/services/mistral/llm.py b/src/pipecat/services/mistral/llm.py
index a2edb4cb6..d280aaada 100644
--- a/src/pipecat/services/mistral/llm.py
+++ b/src/pipecat/services/mistral/llm.py
@@ -32,6 +32,10 @@ class MistralLLMService(OpenAILLMService):
     maintaining full compatibility with OpenAI's interface and functionality.
     """
 
+    # Mistral doesn't support the "developer" message role.
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = MistralLLMSettings
     _settings: Settings
 
diff --git a/src/pipecat/services/ollama/llm.py b/src/pipecat/services/ollama/llm.py
index a24ebfcaf..89488787e 100644
--- a/src/pipecat/services/ollama/llm.py
+++ b/src/pipecat/services/ollama/llm.py
@@ -29,6 +29,11 @@ class OLLamaLLMService(OpenAILLMService):
     providing a compatible interface for running large language models locally.
     """
 
+    # OLLama doesn't support the "developer" message role (it seems to quietly
+    # ignore "developer" messages).
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = OllamaLLMSettings
     _settings: Settings
 
diff --git a/src/pipecat/services/qwen/llm.py b/src/pipecat/services/qwen/llm.py
index 857c89bea..df07467ba 100644
--- a/src/pipecat/services/qwen/llm.py
+++ b/src/pipecat/services/qwen/llm.py
@@ -29,6 +29,10 @@ class QwenLLMService(OpenAILLMService):
     maintaining full compatibility with OpenAI's interface and functionality.
     """
 
+    # Qwen doesn't support the "developer" message role.
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = QwenLLMSettings
     _settings: Settings
 
diff --git a/src/pipecat/services/sambanova/llm.py b/src/pipecat/services/sambanova/llm.py
index 35cf60886..20e17b4f2 100644
--- a/src/pipecat/services/sambanova/llm.py
+++ b/src/pipecat/services/sambanova/llm.py
@@ -41,6 +41,10 @@ class SambaNovaLLMService(OpenAILLMService):  # type: ignore
     maintaining full compatibility with OpenAI's interface and functionality.
     """
 
+    # SambaNova doesn't support the "developer" message role.
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = SambaNovaLLMSettings
     _settings: Settings
 
diff --git a/src/pipecat/services/together/llm.py b/src/pipecat/services/together/llm.py
index 4ec2f8244..80aa91590 100644
--- a/src/pipecat/services/together/llm.py
+++ b/src/pipecat/services/together/llm.py
@@ -29,6 +29,11 @@ class TogetherLLMService(OpenAILLMService):
     maintaining full compatibility with OpenAI's interface and functionality.
     """
 
+    # Together.ai doesn't support the "developer" message role (it seems to quietly
+    # ignore "developer" messages).
+    # This value is used by BaseOpenAILLMService when calling the adapter.
+    supports_developer_role = False
+
     Settings = TogetherLLMSettings
     _settings: Settings