diff --git a/.jules/bolt.md b/.jules/bolt.md
index 2fd177f..84f6346 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -26,3 +26,8 @@
 ## 2024-05-18 - [SQLite Statement Caching]
 **Learning:** better-sqlite3 `db.prepare()` is expensive enough that calling it in a hot loop (like `cached()`) causes significant performance overhead (~4x slower). Statement caching per-database instance is required for hot path queries.
 **Action:** When using better-sqlite3 in frequently called functions (e.g. `cached()` wrapper or event loop hooks), lazily initialize and reuse prepared statements bound to the current database instance instead of preparing the statement on every call.
+
+## 2026-09-28 - Avoid chained map and slice in hot paths
+**Learning:** In `src/tools/technical.ts`, the `indicatorsTool` used chained array methods like `.map()` and `.slice().map()` to extract closes and construct the resulting bars array. This created intermediate array allocations causing significant garbage collection overhead during hot-path technical indicator computation.
+**Action:** Replaced the chained array methods with a single, highly optimized indexed `for` loop to reduce memory allocations and avoid GC pressure.
+
diff --git a/src/tools/technical.ts b/src/tools/technical.ts
index 96223bd..e389911 100644
--- a/src/tools/technical.ts
+++ b/src/tools/technical.ts
@@ -75,12 +75,27 @@ export const indicatorsTool = tool(
     bbStdDev,
   }) => {
     const series = await loadCloses(symbol, kind, resolution as Resolution, bars);
-    const closes = series.map((b) => b.close);
+
+    const len = series.length;
+    // Avoid chained .map() and .slice().map() to reduce memory allocation
+    const closes = new Array(len);
+    for (let i = 0; i < len; i++) {
+      closes[i] = series[i]!.close;
+    }
+
+    const sliceLen = Math.min(len, bars);
+    const startIdx = len - sliceLen;
+    const outBars = new Array(sliceLen);
+    for (let i = 0; i < sliceLen; i++) {
+      const b = series[startIdx + i]!;
+      outBars[i] = { time: b.time, close: b.close };
+    }
+
     const out: Record<string, unknown> = {
       symbol,
       kind,
       resolution,
-      bars: series.slice(-bars).map((b) => ({ time: b.time, close: b.close })),
+      bars: outBars,
       latest_close: last(closes),
     };