diff --git a/packages/tools/src/shared/forget-memory.test.ts b/packages/tools/src/shared/forget-memory.test.ts
new file mode 100644
index 000000000..a97df2f76
--- /dev/null
+++ b/packages/tools/src/shared/forget-memory.test.ts
@@ -0,0 +1,59 @@
+import { afterEach, describe, expect, it, vi } from "vitest"
+import { forgetMemoryRequest } from "./forget-memory"
+
+const originalFetch = globalThis.fetch
+
+afterEach(() => {
+	globalThis.fetch = originalFetch
+	vi.restoreAllMocks()
+})
+
+describe("forgetMemoryRequest signal composition", () => {
+	it("aborts via the caller's signal even though the 30s timeout is also armed", async () => {
+		// Simulate a server that never answers, honoring the signal like real
+		// fetch: rejection on abort proves the composed signal is wired
+		// through to the request.
+		const fetchMock = vi.fn().mockImplementation(
+			(_url: unknown, init?: RequestInit) =>
+				new Promise<Response>((_resolve, reject) => {
+					const signal = init?.signal as AbortSignal | undefined
+					signal?.addEventListener("abort", () => {
+						reject(new Error("aborted"))
+					})
+				}),
+		)
+		globalThis.fetch = fetchMock as unknown as typeof fetch
+
+		const controller = new AbortController()
+		const promise = forgetMemoryRequest(
+			"sm_key",
+			{ containerTag: "c" },
+			"https://api.example.com",
+			{
+				signal: controller.signal,
+			},
+		)
+
+		controller.abort()
+		await expect(promise).rejects.toThrow()
+		expect(fetchMock.mock.calls.length).toBe(1)
+	})
+
+	it("applies the 30s deadline when no caller signal is provided", async () => {
+		const fetchMock = vi.fn().mockImplementation((_url, init) => {
+			const signal = (init as RequestInit).signal as AbortSignal
+			// The timeout must be armed even without a caller signal.
+			expect(signal).toBeTruthy()
+			return Promise.resolve(new Response(null, { status: 200 }))
+		})
+		globalThis.fetch = fetchMock as unknown as typeof fetch
+
+		await expect(
+			forgetMemoryRequest(
+				"sm_key",
+				{ containerTag: "c" },
+				"https://api.example.com",
+			),
+		).resolves.toBeUndefined()
+	})
+})
diff --git a/packages/tools/src/shared/forget-memory.ts b/packages/tools/src/shared/forget-memory.ts
index 8691c92ac..184bd960c 100644
--- a/packages/tools/src/shared/forget-memory.ts
+++ b/packages/tools/src/shared/forget-memory.ts
@@ -33,7 +33,13 @@ export async function forgetMemoryRequest(
 			Authorization: `Bearer ${apiKey}`,
 		},
 		body: JSON.stringify(params),
-		signal: options?.signal ?? AbortSignal.timeout(FETCH_TIMEOUT_MS),
+		// Compose, don't choose: `??` let a caller-supplied signal silently
+		// drop the 30s safety timeout (and vice versa). Any signal firing —
+		// caller abort or the deadline — must abort the request.
+		signal: AbortSignal.any([
+			...(options?.signal ? [options.signal] : []),
+			AbortSignal.timeout(FETCH_TIMEOUT_MS),
+		]),
 	})
 
 	if (!response.ok) {