diff --git a/extensions/active-memory/index.test.ts b/extensions/active-memory/index.test.ts
index f06ac70a61b..16863c882ba 100644
--- a/extensions/active-memory/index.test.ts
+++ b/extensions/active-memory/index.test.ts
@@ -4812,13 +4812,14 @@ describe("active-memory plugin", () => {
     ).not.toEqual([]);
   });
 
-  it("caps active-memory log field lengths", async () => {
+  it("caps active-memory log field lengths without splitting surrogate pairs", async () => {
     api.pluginConfig = {
       agents: ["main"],
       logging: true,
     };
     plugin.register(api as unknown as OpenClawPluginApi);
-    const hugeSession = `agent:main:${"x".repeat(500)}`;
+    const sessionPrefix = `agent:main:${"x".repeat(288)}`;
+    const hugeSession = `${sessionPrefix}😀tail`;
 
     await hooks.before_prompt_build(
       { prompt: "what wings should i order? long log value", messages: [] },
@@ -4836,7 +4837,8 @@ describe("active-memory plugin", () => {
     const startLine = infoLines.find((line: string) => line.includes(" start timeoutMs="));
     const line = requireNonEmptyString(startLine, "active memory start log line missing");
     expect(line.length).toBeLessThan(500);
-    expect(line).toContain("...");
+    expect(line).toContain(`session=${sessionPrefix}...`);
+    expect(line).not.toMatch(/[\uD800-\uDFFF]/u);
   });
 
   it("uses a canonical agent session key when only sessionId is available", async () => {
diff --git a/extensions/active-memory/index.ts b/extensions/active-memory/index.ts
index 594b1e5f037..a06458ff3d4 100644
--- a/extensions/active-memory/index.ts
+++ b/extensions/active-memory/index.ts
@@ -1434,7 +1434,7 @@ function toSingleLineLogValue(value: unknown): string {
     .replace(/\s+/g, " ")
     .trim();
   return singleLine.length > MAX_LOG_VALUE_CHARS
-    ? `${singleLine.slice(0, MAX_LOG_VALUE_CHARS)}...`
+    ? `${truncateUtf16Safe(singleLine, MAX_LOG_VALUE_CHARS)}...`
     : singleLine;
 }