diff --git a/astrbot/core/provider/sources/openai_source.py b/astrbot/core/provider/sources/openai_source.py
index 2fae94e1a7..6848c5d43a 100644
--- a/astrbot/core/provider/sources/openai_source.py
+++ b/astrbot/core/provider/sources/openai_source.py
@@ -313,7 +313,8 @@ async def _query_stream(
                 logger.warning("Saving chunk state error: " + str(e))
             if not chunk.choices:
                 continue
-            delta = chunk.choices[0].delta
+            choice = chunk.choices[0]
+            delta = choice.delta
             # logger.debug(f"chunk delta: {delta}")
             # handle the content delta
             reasoning = self._extract_reasoning_content(chunk)
@@ -331,6 +332,11 @@ async def _query_stream(
                 _y = True
             if chunk.usage:
                 llm_response.usage = self._extract_usage(chunk.usage)
+            elif choice_usage := getattr(choice, "usage", None):
+                # Workaround for some providers that only return usage in choices[].usage, e.g. MoonshotAI
+                # See https://github.com/AstrBotDevs/AstrBot/issues/6614
+                llm_response.usage = self._extract_usage(choice_usage)
+                state.current_completion_snapshot.usage = choice_usage
             if _y:
                 yield llm_response
 
@@ -359,13 +365,11 @@ def _extract_reasoning_content(
                 reasoning_text = str(reasoning_attr)
         return reasoning_text
 
-    def _extract_usage(self, usage: CompletionUsage) -> TokenUsage:
-        ptd = usage.prompt_tokens_details
-        cached = ptd.cached_tokens if ptd and ptd.cached_tokens else 0
-        prompt_tokens = 0 if usage.prompt_tokens is None else usage.prompt_tokens
-        completion_tokens = (
-            0 if usage.completion_tokens is None else usage.completion_tokens
-        )
+    def _extract_usage(self, usage: CompletionUsage | dict) -> TokenUsage:
+        ptd = getattr(usage, "prompt_tokens_details", None)
+        cached = getattr(ptd, "cached_tokens", 0) if ptd else 0
+        prompt_tokens = getattr(usage, "prompt_tokens", 0) or 0
+        completion_tokens = getattr(usage, "completion_tokens", 0) or 0
         return TokenUsage(
             input_other=prompt_tokens - cached,
             input_cached=cached,