diff --git a/rivetkit-typescript/packages/rivetkit/tests/fixtures/napi-runtime-server.ts b/rivetkit-typescript/packages/rivetkit/tests/fixtures/napi-runtime-server.ts
index a7fedd554d..0a95c209db 100644
--- a/rivetkit-typescript/packages/rivetkit/tests/fixtures/napi-runtime-server.ts
+++ b/rivetkit-typescript/packages/rivetkit/tests/fixtures/napi-runtime-server.ts
@@ -7,7 +7,6 @@ import { db } from "../../src/db/mod";
 import { actor, event, queue, setup, UserError } from "../../src/mod";
 import { buildNativeRegistry } from "../../src/registry/native";
 
-const textDecoder = new TextDecoder();
 const fixtureDir = dirname(fileURLToPath(import.meta.url));
 const repoEngineBinary = resolve(
 	fixtureDir,
@@ -79,9 +78,10 @@ const integrationActor = actor({
 			await c.db.execute(
 				"CREATE TABLE IF NOT EXISTS increments (value INTEGER NOT NULL)",
 			);
-			await c.db.execute("INSERT INTO increments (value) VALUES (?)", [
+			await c.db.execute(
+				"INSERT INTO increments (value) VALUES (?)",
 				c.state.count,
-			]);
+			);
 
 			const rows = await c.db.execute<{ value: number }>(
 				"SELECT value FROM increments ORDER BY rowid ASC",
@@ -102,7 +102,7 @@ const integrationActor = actor({
 
 			return {
 				count: c.state.count,
-				kvCount: kvValue ? Number(textDecoder.decode(kvValue)) : null,
+				kvCount: kvValue ? Number(kvValue) : null,
 				sqliteValues: rows.map(({ value }) => Number(value)),
 			};
 		},
@@ -117,12 +117,14 @@ const integrationActor = actor({
 			const kvValue = await c.kv.get("count");
 			return {
 				count: c.state.count,
-				kvCount: kvValue ? Number(textDecoder.decode(kvValue)) : null,
+				kvCount: kvValue ? Number(kvValue) : null,
 			};
 		},
 		getCountViaClient: async (c) => {
 			const client = c.client<any>();
-			return await client.integrationActor.getForId(c.actorId).getCount();
+			return await client.integrationActor
+				.getForId(c.actorId, { params: c.conn.params })
+				.getCount();
 		},
 		throwTypedError: async () => {
 			throw new UserError("native typed error", {
@@ -159,4 +161,20 @@ const { registry: nativeRegistry, serveConfig } = await buildNativeRegistry(
 );
 serveConfig.engineBinaryPath = resolveEngineBinaryPath();
 
-await nativeRegistry.serve(serveConfig);
+const shutdown = new Promise<"signal">((resolve) => {
+	process.once("SIGINT", () => resolve("signal"));
+});
+const serving = nativeRegistry.serve(serveConfig);
+
+await nativeRegistry.waitReady();
+const stopReason = await Promise.race([
+	shutdown,
+	serving.then(() => "registry" as const),
+]);
+if (stopReason === "registry") {
+	throw new Error(
+		"native registry stopped before the test requested shutdown",
+	);
+}
+await nativeRegistry.shutdown();
+await serving;
diff --git a/rivetkit-typescript/packages/rivetkit/tests/napi-runtime-integration.test.ts b/rivetkit-typescript/packages/rivetkit/tests/napi-runtime-integration.test.ts
index c5c605017b..ade7af7afb 100644
--- a/rivetkit-typescript/packages/rivetkit/tests/napi-runtime-integration.test.ts
+++ b/rivetkit-typescript/packages/rivetkit/tests/napi-runtime-integration.test.ts
@@ -291,9 +291,10 @@ describe.sequential("native NAPI runtime integration", () => {
 
 		const handle = await waitForActorReady(
 			() =>
-				client.integrationActor.create([
-					`napi-runtime-${crypto.randomUUID()}`,
-				]),
+				client.integrationActor.create(
+					[`napi-runtime-${crypto.randomUUID()}`],
+					{ params: { userId: "native-integration-test" } },
+				),
 			30_000,
 		);
 		const actorId = await handle.resolve();
@@ -384,7 +385,7 @@ describe.sequential("native NAPI runtime integration", () => {
 			},
 		});
 		await expect(handle.throwUntypedError()).rejects.toMatchObject({
-			group: "core",
+			group: "rivetkit",
 			code: "internal_error",
 			message: "An internal error occurred",
 		});