diff --git a/.jules/bolt.md b/.jules/bolt.md
index 341c7c91..4c84e31d 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -67,3 +67,6 @@
 ## 2025-02-12 - [Fast Path Execution in Directory Traversal and Log Parsing]
 **Learning:** Checking for string existence (`if "silence_" not in stderr`) before invoking regex matchers provides significant speed improvements when parsing large blocks of text. Similarly, moving expensive I/O operations like `os.path.realpath` inside conditional blocks prevents redundant disk access when configuration (like path exclusions) isn't utilized.
 **Action:** When working on large text processing or disk operations, verify if early exit conditions or conditional execution can bypass the expensive system or library calls.
+## 2024-10-11 - Optimize set intersection in TranscriptIndex
+**Learning:** In Python, when iteratively intersecting sets within a loop, using the `.intersection_update()` method modifies the set in-place, avoiding intermediate memory allocations compared to the `&` operator.
+**Action:** Use `.intersection_update()` for set intersections in hot loops.
diff --git a/transcript_search.py b/transcript_search.py
index 1660c1f2..36f493df 100644
--- a/transcript_search.py
+++ b/transcript_search.py
@@ -241,9 +241,11 @@ def search(self, query: str) -> list[Match]:
             postings = self._postings.get(term)
             if not postings:
                 return []
-            candidates = (
-                set(postings) if candidates is None else candidates & postings
-            )
+            if candidates is None:
+                candidates = set(postings)
+            else:
+                # ⚡ Bolt: in-place 교집합 연산으로 중간 세트 메모리 할당 방지
+                candidates.intersection_update(postings)
             if not candidates:
                 return []