diff --git a/plugins/ai_auto_response/main.py b/plugins/ai_auto_response/main.py
index e1bf312..d190ed6 100644
--- a/plugins/ai_auto_response/main.py
+++ b/plugins/ai_auto_response/main.py
@@ -608,6 +608,21 @@ class AIAutoResponsePlugin(MessagePluginInterface):
                 fallback_reply_mode=reply_mode,
                 fallback_topic=trigger.topic or "",
             )
+            # 这里补一条完整的模型决策日志：
+            # 1. 无论模型最终决定回还是不回，都先把 should_reply / reply_mode / topic / reply 预览记下来；
+            # 2. 同时保留 sanitize 后的原始响应预览，方便排查“模型其实回了什么 JSON / 文本”；
+            # 3. 这样后面即使被 cooldown、过期、去重拦住，也能明确看到“模型本来想怎么做”。
+            self._log_event(
+                "llm_result",
+                room_id=room_id,
+                sender=sender,
+                trigger_type=trigger.trigger_type,
+                should_reply=bool(llm_result.get("should_reply", True)),
+                reply_mode=str(llm_result.get("reply_mode", reply_mode) or reply_mode),
+                topic=str(llm_result.get("topic_summary", "") or llm_result.get("topic_id", "") or trigger.topic or ""),
+                response_preview=preview_text(str(llm_result.get("reply", "") or ""), 120),
+                raw_response_preview=preview_text(response, 160),
+            )
             if not llm_result.get("should_reply", True):
                 self._log_event(
                     "skip",
@@ -639,6 +654,16 @@ class AIAutoResponsePlugin(MessagePluginInterface):
             # 2. 模型先统一判断 should_reply，只有当它明确想回时，才进入频率控制；
             # 3. 仍然保留冷却，是为了守住群内刷屏风险，但职责已经变成“限制发送”，不是“替模型做语义裁决”。
             if not self.cooldown.pass_cooldown(room_id, sender, trigger.__dict__):
+                self._log_event(
+                    "blocked_reply",
+                    room_id=room_id,
+                    sender=sender,
+                    reason=f"post_llm_{trigger.__dict__.get('_cooldown_reason', 'cooldown')}",
+                    trigger_type=trigger.trigger_type,
+                    reply_mode=reply_mode,
+                    topic=selected_topic,
+                    response_preview=preview_text(reply_text, 120),
+                )
                 self._log_event(
                     "skip",
                     room_id=room_id,
@@ -657,6 +682,17 @@ class AIAutoResponsePlugin(MessagePluginInterface):
             # 2. 即使消息进模型时还新鲜，等模型回完也可能已经跟不上群聊了；
             # 3. 这种情况下直接放弃发送，比突然补回旧话更自然。
             if self._is_message_stale(message):
+                self._log_event(
+                    "blocked_reply",
+                    room_id=room_id,
+                    sender=sender,
+                    reason="stale_before_send",
+                    trigger_type=trigger.trigger_type,
+                    reply_mode=reply_mode,
+                    topic=selected_topic,
+                    response_preview=preview_text(final_response_text, 120),
+                    age_sec=round(self._get_message_queue_age_sec(message), 2),
+                )
                 self._log_event(
                     "skip",
                     room_id=room_id,
@@ -673,6 +709,16 @@ class AIAutoResponsePlugin(MessagePluginInterface):
             # 2. 这时即使模型产出了结果，也不应该再把旧回复补发出去；
             # 3. 直接丢弃旧结果，让群里只看到贴着最新现场的回复。
             if self._is_message_superseded(message):
+                self._log_event(
+                    "blocked_reply",
+                    room_id=room_id,
+                    sender=sender,
+                    reason="superseded_before_send",
+                    trigger_type=trigger.trigger_type,
+                    reply_mode=reply_mode,
+                    topic=selected_topic,
+                    response_preview=preview_text(final_response_text, 120),
+                )
                 self._log_event(
                     "skip",
                     room_id=room_id,
@@ -690,6 +736,16 @@ class AIAutoResponsePlugin(MessagePluginInterface):
                 reply_text=final_response_text,
                 expiry_sec=reply_dedup_expiry,
             ):
+                self._log_event(
+                    "blocked_reply",
+                    room_id=room_id,
+                    sender=sender,
+                    reason="duplicate_reply",
+                    trigger_type=trigger.trigger_type,
+                    reply_mode=reply_mode,
+                    topic=selected_topic,
+                    response_preview=preview_text(final_response_text, 120),
+                )
                 self._log_event(
                     "skip",
                     room_id=room_id,
diff --git a/plugins/ai_auto_response/runtime/logging.py b/plugins/ai_auto_response/runtime/logging.py
index c9353a3..555f348 100644
--- a/plugins/ai_auto_response/runtime/logging.py
+++ b/plugins/ai_auto_response/runtime/logging.py
@@ -76,6 +76,31 @@ def build_log_summary(event: str, data: Dict[str, Any]) -> str:
             f"err={data.get('last_error', '')}"
         ).strip()
 
+    if event == "llm_result":
+        return (
+            f"[XIAONIU] LLM_RESULT room={room} user={sender} "
+            f"trigger={data.get('trigger_type', 'none')} "
+            f"want={yn(data.get('should_reply'))} "
+            f"mode={data.get('reply_mode', '')} "
+            f"topic={data.get('topic', '-') or '-'} "
+            f"reply={data.get('response_preview', '')} "
+            f"raw={data.get('raw_response_preview', '')}"
+        ).strip()
+
+    if event == "blocked_reply":
+        age_text = ""
+        if data.get("age_sec") not in (None, ""):
+            age_text = f" age={data.get('age_sec')}"
+        return (
+            f"[XIAONIU] BLOCKED_REPLY room={room} user={sender} "
+            f"reason={data.get('reason', '')} "
+            f"trigger={data.get('trigger_type', 'none')} "
+            f"mode={data.get('reply_mode', '')} "
+            f"topic={data.get('topic', '-') or '-'} "
+            f"reply={data.get('response_preview', '')}"
+            f"{age_text}"
+        ).strip()
+
     if event == "sent":
         return (
             f"[XIAONIU] SENT room={room} user={sender_name}/{sender} "