diff --git a/packages/memory-host-sdk/src/host/qmd-query-parser.test.ts b/packages/memory-host-sdk/src/host/qmd-query-parser.test.ts
index 8f14646cb8b4..e41d16069f64 100644
--- a/packages/memory-host-sdk/src/host/qmd-query-parser.test.ts
+++ b/packages/memory-host-sdk/src/host/qmd-query-parser.test.ts
@@ -60,6 +60,15 @@ complete`,
     expect(parseQmdQueryJson("", "[qmd] warning: no results found\n")).toStrictEqual([]);
   });
 
+  it("keeps bounded stderr context UTF-16 safe", () => {
+    const prefix = "a".repeat(116);
+    const stderr = `${prefix}😀${"b".repeat(120)}`;
+
+    expect(() => parseQmdQueryJson("", stderr)).toThrow(
+      `qmd query returned invalid JSON: stdout empty (stderr: ${prefix}...)`,
+    );
+  });
+
   it("does not treat arbitrary non-marker text as no-results output", () => {
     expect(() =>
       parseQmdQueryJson("warning: search completed; no results found for this query", ""),
diff --git a/packages/memory-host-sdk/src/host/qmd-query-parser.ts b/packages/memory-host-sdk/src/host/qmd-query-parser.ts
index a8be1db36958..5a31a376a07e 100644
--- a/packages/memory-host-sdk/src/host/qmd-query-parser.ts
+++ b/packages/memory-host-sdk/src/host/qmd-query-parser.ts
@@ -1,4 +1,5 @@
 // Memory Host SDK module implements qmd query parser behavior.
+import { truncateUtf16Safe } from "@openclaw/normalization-core/utf16-slice";
 import { formatErrorMessage } from "./error-utils.js";
 import { normalizeLowercaseStringOrEmpty } from "./string-utils.js";
 
@@ -81,7 +82,7 @@ function isQmdNoResultsLine(line: string): boolean {
 
 /** Bound stderr context included in parse errors. */
 function summarizeQmdStderr(raw: string): string {
-  return raw.length <= 120 ? raw : `${raw.slice(0, 117)}...`;
+  return raw.length <= 120 ? raw : `${truncateUtf16Safe(raw, 117)}...`;
 }
 
 /** Parse and normalize a strict qmd JSON array payload. */