diff --git a/astrbot/core/provider/sources/openai_source.py b/astrbot/core/provider/sources/openai_source.py
index e1aa08542..00c1f0a15 100644
--- a/astrbot/core/provider/sources/openai_source.py
+++ b/astrbot/core/provider/sources/openai_source.py
@@ -944,11 +944,13 @@ class ProviderOpenAIOfficial(Provider):
         """Finally convert the payload. Such as think part conversion, tool inject."""
         model = payloads.get("model", "").lower()
         is_gemini = "gemini" in model
-        deepseek_reasoning_models = {"deepseek-v4-pro", "deepseek-v4-flash"}
+        _deepseek_v4_markers = ("deepseek-v4-pro", "deepseek-v4-flash", "deepseek-v4")
         is_deepseek_v4_reasoning = (
-            model in deepseek_reasoning_models
+            any(marker in model for marker in _deepseek_v4_markers)
             or "api.deepseek.com" in self.client.base_url.host
         )
+        # deepseek-chat and deepseek-reasoner now point to V4 models (per official website)
+
         # MiMo 推理模型（MiMo-V2.5-Pro / MiMo-V2.5 / MiMo-V2-Pro / MiMo-V2-Omni / MiMo-V2-Flash）
         # 要求 assistant 历史消息必须回传 reasoning_content，否则返回 400
         mimo_reasoning_models = {