diff --git a/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/registry-static.ts b/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/registry-static.ts
index 832e1065ee..ca3878679e 100644
--- a/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/registry-static.ts
+++ b/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/registry-static.ts
@@ -113,6 +113,7 @@ import {
 	sleepRawWsDelayedSendOnSleep,
 	sleepWithWaitUntilInOnWake,
 	sleepAbortListenerVarsActor,
+	sleepRawWsVarsExceedsGrace,
 } from "./sleep";
 import {
 	sleepWithDb,
@@ -210,6 +211,7 @@ export const registry = setup({
 		sleepRawWsDelayedSendOnSleep,
 		sleepWithWaitUntilInOnWake,
 		sleepAbortListenerVarsActor,
+		sleepRawWsVarsExceedsGrace,
 		counterWaitUntilProbe,
 		// From sleep-db.ts
 		sleepWithDb,
diff --git a/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/sleep.ts b/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/sleep.ts
index 56fb3aa865..c8e2602a98 100644
--- a/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/sleep.ts
+++ b/rivetkit-typescript/packages/rivetkit/fixtures/driver-test-suite/sleep.ts
@@ -618,3 +618,71 @@ export const sleepWithNoSleepOption = actor({
 		noSleep: true,
 	},
 });
+
+// Reproduces a production crash where c.vars becomes undefined after the
+// grace deadline expires and clearNativeRuntimeState unrefs the NAPI
+// runtime state object. An async message handler accesses c.vars after an
+// await that outlasts the grace period.
+//
+// The close-handler variant cannot reproduce the bug because the tracked
+// websocket callback region blocks can_arm_sleep_timer. Instead we use a
+// message handler that starts slow async work, then the actor is told to
+// sleep programmatically while the handler is still running.
+export const VARS_EXCEEDS_GRACE_DELAY = 2000;
+export const VARS_EXCEEDS_GRACE_PERIOD = 200;
+export const VARS_EXCEEDS_GRACE_SLEEP_TIMEOUT = 100;
+
+export const sleepRawWsVarsExceedsGrace = actor({
+	state: {
+		startCount: 0,
+		sleepCount: 0,
+		handlerStarted: 0,
+		handlerFinished: 0,
+	},
+	createVars: () => ({
+		dirty: false,
+	}),
+	onWake: (c) => {
+		c.state.startCount += 1;
+	},
+	onSleep: (c) => {
+		c.state.sleepCount += 1;
+	},
+	onWebSocket: (c, websocket: UniversalWebSocket) => {
+		websocket.addEventListener("message", async (event: any) => {
+			if (event.data !== "slow-vars-work") return;
+
+			c.state.handlerStarted += 1;
+			websocket.send(JSON.stringify({ type: "started" }));
+
+			// Wait longer than the grace period so the runtime state
+			// gets cleared while this handler is still running.
+			await new Promise((resolve) =>
+				setTimeout(resolve, VARS_EXCEEDS_GRACE_DELAY),
+			);
+			// This c.vars access crashes with TypeError in prod because
+			// the NAPI runtime state reference has been unreffed.
+			// Do NOT wrap in try/catch: c.state also breaks after cleanup,
+			// so the error needs to propagate to the process level.
+			c.vars.dirty = true;
+			c.state.handlerFinished += 1;
+		});
+
+		websocket.send(JSON.stringify({ type: "connected" }));
+	},
+	actions: {
+		triggerSleep: (c) => {
+			c.sleep();
+		},
+		getStatus: (c) => ({
+			startCount: c.state.startCount,
+			sleepCount: c.state.sleepCount,
+			handlerStarted: c.state.handlerStarted,
+			handlerFinished: c.state.handlerFinished,
+		}),
+	},
+	options: {
+		sleepTimeout: VARS_EXCEEDS_GRACE_SLEEP_TIMEOUT,
+		sleepGracePeriod: VARS_EXCEEDS_GRACE_PERIOD,
+	},
+});
diff --git a/rivetkit-typescript/packages/rivetkit/src/registry/native.ts b/rivetkit-typescript/packages/rivetkit/src/registry/native.ts
index 633bddd9df..e64321b38e 100644
--- a/rivetkit-typescript/packages/rivetkit/src/registry/native.ts
+++ b/rivetkit-typescript/packages/rivetkit/src/registry/native.ts
@@ -2335,7 +2335,7 @@ class TrackedWebSocketHandleAdapter implements UniversalWebSocket {
 				return;
 			}
 			const callbackRegionId = this.#ctx.beginWebSocketCallback();
-			this.#ctx.waitUntil(
+			this.#ctx.keepAwake(
 				Promise.resolve(result)
 					.catch((error) => {
 						logger().error({
diff --git a/rivetkit-typescript/packages/rivetkit/tests/driver/actor-sleep.test.ts b/rivetkit-typescript/packages/rivetkit/tests/driver/actor-sleep.test.ts
index 28fc0a76d6..a3bd92f8d2 100644
--- a/rivetkit-typescript/packages/rivetkit/tests/driver/actor-sleep.test.ts
+++ b/rivetkit-typescript/packages/rivetkit/tests/driver/actor-sleep.test.ts
@@ -5,6 +5,8 @@ import {
 	RAW_WS_HANDLER_DELAY,
 	RAW_WS_HANDLER_SLEEP_TIMEOUT,
 	SLEEP_TIMEOUT,
+	VARS_EXCEEDS_GRACE_DELAY,
+	VARS_EXCEEDS_GRACE_SLEEP_TIMEOUT,
 } from "../../fixtures/driver-test-suite/sleep";
 import { describeDriverMatrix } from "./shared-matrix";
 import { setupDriverTest, waitFor } from "./shared-utils";
@@ -962,5 +964,69 @@ describeDriverMatrix("Actor Sleep", (driverTestConfig) => {
 				expect(startCount).toBe(2);
 			}
 		});
+
+		test(
+			"c.vars access in ws handler should not crash after grace deadline",
+			async (c) => {
+				const { client, getRuntimeOutput } = await setupDriverTest(
+					c,
+					driverTestConfig,
+				);
+
+				const actor =
+					client.sleepRawWsVarsExceedsGrace.getOrCreate([
+						"ws-vars-exceeds-grace",
+					]);
+				const ws = await connectRawWebSocket(actor);
+
+				// Send a message that starts slow async work (2000ms delay
+				// before accessing c.vars).
+				ws.send("slow-vars-work");
+
+				// Wait for the handler to confirm it started.
+				await new Promise<void>((resolve) => {
+					const onMessage = (event: MessageEvent) => {
+						const data = JSON.parse(String(event.data));
+						if (data.type === "started") {
+							ws.removeEventListener("message", onMessage);
+							resolve();
+						}
+					};
+					ws.addEventListener("message", onMessage);
+				});
+
+				// Trigger sleep while the handler is still doing slow work.
+				// The grace period (200ms) is much shorter than the handler
+				// delay (2000ms), so onSleep will clear the runtime state
+				// while the handler is still running.
+				await actor.triggerSleep();
+
+				// Wait for the handler to finish and the actor to complete
+				// its sleep cycle.
+				await waitFor(
+					driverTestConfig,
+					VARS_EXCEEDS_GRACE_DELAY +
+						VARS_EXCEEDS_GRACE_SLEEP_TIMEOUT +
+						500,
+				);
+
+				// Wake the actor and check what happened.
+				const status = await actor.getStatus();
+				expect(status.sleepCount).toBeGreaterThanOrEqual(1);
+				expect(status.handlerStarted).toBe(1);
+				// The runtime must not crash with TypeError when the
+				// handler accesses c.vars after the grace deadline.
+				// The deferred cleanup keeps the runtime state alive
+				// until the websocket callback region drains.
+				const output = getRuntimeOutput();
+				expect(output).not.toContain(
+					"Cannot set properties of undefined",
+				);
+				expect(output).not.toContain(
+					"Cannot read properties of undefined",
+				);
+			},
+			{ timeout: 15_000 },
+		);
 	});
 });