diff --git a/docs/research/distill-scan-pangtong.py b/docs/research/distill-scan-pangtong.py
index 25f67d9..3eb5bbb 100644
--- a/docs/research/distill-scan-pangtong.py
+++ b/docs/research/distill-scan-pangtong.py
@@ -363,6 +363,10 @@ def scan_trial_error(messages: list) -> list:
 
 def scan_success(messages: list) -> list:
     """Pattern ③: Complex task (5+ tool_use in a session) with no correction."""
+    # Need at least 4 messages to be meaningful
+    if len(messages) < 4:
+        return []
+
     # First check if the session has any corrections
     has_correction = any(
         m.role == 'user' and match_signals(m.text, CORRECTION_SIGNALS)
@@ -379,29 +383,27 @@ def scan_success(messages: list) -> list:
     if len(all_tools) < 5:
         return []
 
-    # Find the richest assistant message (most tool_use)
-    best_msg = None
-    best_count = 0
-    for m in messages:
-        if m.role == 'assistant' and len(m.tool_names) > best_count:
-            best_count = len(m.tool_names)
-            best_msg = m
-
-    if not best_msg:
+    # Use the last assistant message as the completion point
+    last_asst = None
+    for m in reversed(messages):
+        if m.role == 'assistant':
+            last_asst = m
+            break
+    if not last_asst:
         return []
 
-    ctx_before, ctx_after = get_context(messages, best_msg.idx)
-    tools = get_tools_in_context(messages, best_msg.idx)
+    ctx_before, ctx_after = get_context(messages, last_asst.idx)
+    tools = get_tools_in_context(messages, last_asst.idx)
 
     return [{
         'mode': 'success',
-        'timestamp': best_msg.timestamp,
-        'trigger_message': best_msg.raw_text_snippet,
+        'timestamp': last_asst.timestamp,
+        'trigger_message': last_asst.raw_text_snippet,
         'trigger_role': 'assistant',
         'context_before': ctx_before,
         'context_after': ctx_after,
         'tool_calls_in_context': tools,
-        'summary': f"复杂任务成功完成，共使用 {len(all_tools)} 次 tool_call"
+        'summary': f"复杂任务成功完成，共使用 {len(all_tools)} 次 tool_call，无用户纠正"
     }]