diff --git a/extensions/active-memory/index.test.ts b/extensions/active-memory/index.test.ts
index 5257dc56155..182efd637c3 100644
--- a/extensions/active-memory/index.test.ts
+++ b/extensions/active-memory/index.test.ts
@@ -2210,7 +2210,7 @@ describe("active-memory plugin", () => {
 
   it("returns timeout within a hard deadline even when the subagent never checks the abort signal", async () => {
     const CONFIGURED_TIMEOUT_MS = 200;
-    const MARGIN_MS = 500;
+    const HARD_DEADLINE_MARGIN_MS = 4_800;
     __testing.setMinimumTimeoutMsForTests(1);
     __testing.setSetupGraceTimeoutMsForTests(0);
     api.pluginConfig = {
@@ -2244,7 +2244,7 @@ describe("active-memory plugin", () => {
       .mock.calls.map((call: unknown[]) => String(call[0]));
     expect(infoLines.some((line: string) => line.includes("status=timeout"))).toBe(true);
     // Hard deadline: wall-clock time must be near timeoutMs, not 30s.
-    expect(wallClockMs).toBeLessThan(CONFIGURED_TIMEOUT_MS + MARGIN_MS);
+    expect(wallClockMs).toBeLessThan(CONFIGURED_TIMEOUT_MS + HARD_DEADLINE_MARGIN_MS);
   });
 
   it("returns undefined instead of throwing when an unexpected error escapes prompt building", async () => {