fix(llm): adapt async tool results for compatible APIs

backend/services/pipecat/service_factory.py

@@ -117,7 +117,7 @@ def create_llm(cfg: AssistantConfig):
         raise ValueError(f"不支持的 LLM 接口类型: {cfg.llm_interface_type}")
     extra_body = cfg.llm_values.get("extraBody")
     extra = {"extra_body": extra_body} if isinstance(extra_body, dict) else {}
-    return OpenAILLMService(
+    service = OpenAILLMService(
         api_key=_require(cfg.llm_api_key, "LLM apiKey"),
         base_url=_require(cfg.llm_base_url, "LLM apiUrl"),
         settings=OpenAILLMService.Settings(
@@ -125,6 +125,15 @@ def create_llm(cfg: AssistantConfig):
             extra=extra,
         ),
     )
+    # Pipecat represents late async-tool results with the newer `developer`
+    # role. Most OpenAI-compatible providers (including DeepSeek) only accept
+    # system/assistant/user/tool. This flag uses Pipecat's built-in adapter to
+    # downgrade developer messages before sending the request. Official or
+    # otherwise compatible endpoints can opt in through the resource values.
+    service.supports_developer_role = (
+        cfg.llm_values.get("supportsDeveloperRole") is True
+    )
+    return service
 
 
 def create_tts(cfg: AssistantConfig):