fix: harden node bridge keepalive

src/infra/bridge/server.test.ts

@@ -3,10 +3,10 @@ import net from "node:net";
 import os from "node:os";
 import path from "node:path";
 
-import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { afterAll, beforeAll, describe, expect, it, vi } from "vitest";
 
 import { approveNodePairing, listNodePairing } from "../node-pairing.js";
-import { startNodeBridgeServer } from "./server.js";
+import { configureNodeBridgeSocket, startNodeBridgeServer } from "./server.js";
 
 function createLineReader(socket: net.Socket) {
   let buffer = "";
@@ -70,6 +70,16 @@ describe("node bridge server", () => {
     delete process.env.CLAWDBOT_ENABLE_BRIDGE_IN_TESTS;
   });
 
+  it("enables keepalive on sockets", () => {
+    const socket = {
+      setNoDelay: vi.fn(),
+      setKeepAlive: vi.fn(),
+    };
+    configureNodeBridgeSocket(socket);
+    expect(socket.setNoDelay).toHaveBeenCalledWith(true);
+    expect(socket.setKeepAlive).toHaveBeenCalledWith(true, 15_000);
+  });
+
   it("rejects hello when not paired", async () => {
     const server = await startNodeBridgeServer({
       host: "127.0.0.1",

src/infra/bridge/server.ts

@@ -160,6 +160,14 @@ function isTestEnv() {
   return process.env.NODE_ENV === "test" || Boolean(process.env.VITEST);
 }
 
+export function configureNodeBridgeSocket(socket: {
+  setNoDelay: (noDelay?: boolean) => void;
+  setKeepAlive: (enable?: boolean, initialDelay?: number) => void;
+}) {
+  socket.setNoDelay(true);
+  socket.setKeepAlive(true, 15_000);
+}
+
 function encodeLine(frame: AnyBridgeFrame) {
   return `${JSON.stringify(frame)}\n`;
 }
@@ -228,7 +236,7 @@ export async function startNodeBridgeServer(
   const loopbackHost = "127.0.0.1";
 
   const onConnection = (socket: net.Socket) => {
-    socket.setNoDelay(true);
+    configureNodeBridgeSocket(socket);
 
     let buffer = "";
     let isAuthenticated = false;