fix(bonjour): default mdns host to system hostname

extensions/bonjour/src/advertiser.test.ts

@@ -704,11 +704,57 @@ describe("gateway bonjour advertiser", () => {
     });
 
     const [gatewayCall] = createService.mock.calls as Array<[ServiceCall]>;
-    expect(gatewayCall?.[0]?.name).toBe("openclaw (OpenClaw)");
+    expect(gatewayCall?.[0]?.name).toBe("Mac (OpenClaw)");
     expect(gatewayCall?.[0]?.domain).toBe("local");
+    expect(gatewayCall?.[0]?.hostname).toBe("Mac");
+    expect((gatewayCall?.[0]?.txt as Record<string, string>)?.lanHost).toBe("Mac.local");
+
+    await started.stop();
+  });
+
+  it("falls back to openclaw when system hostname is invalid for DNS", async () => {
+    // Allow advertiser to run in unit tests.
+    delete process.env.VITEST;
+    process.env.NODE_ENV = "development";
+    delete process.env.OPENCLAW_MDNS_HOSTNAME;
+    vi.spyOn(os, "hostname").mockReturnValue("My_Lobster Host");
+
+    const destroy = vi.fn().mockResolvedValue(undefined);
+    const advertise = vi.fn().mockResolvedValue(undefined);
+    mockCiaoService({ advertise, destroy });
+
+    const started = await startAdvertiser({
+      gatewayPort: 18789,
+      sshPort: 2222,
+    });
+
+    const [gatewayCall] = createService.mock.calls as Array<[ServiceCall]>;
     expect(gatewayCall?.[0]?.hostname).toBe("openclaw");
     expect((gatewayCall?.[0]?.txt as Record<string, string>)?.lanHost).toBe("openclaw.local");
 
     await started.stop();
   });
+
+  it("uses system hostname when OPENCLAW_MDNS_HOSTNAME is unset", async () => {
+    // Allow advertiser to run in unit tests.
+    delete process.env.VITEST;
+    process.env.NODE_ENV = "development";
+    delete process.env.OPENCLAW_MDNS_HOSTNAME;
+    vi.spyOn(os, "hostname").mockReturnValue("Lobster");
+
+    const destroy = vi.fn().mockResolvedValue(undefined);
+    const advertise = vi.fn().mockResolvedValue(undefined);
+    mockCiaoService({ advertise, destroy });
+
+    const started = await startAdvertiser({
+      gatewayPort: 18789,
+      sshPort: 2222,
+    });
+
+    const [gatewayCall] = createService.mock.calls as Array<[ServiceCall]>;
+    expect(gatewayCall?.[0]?.hostname).toBe("Lobster");
+    expect((gatewayCall?.[0]?.txt as Record<string, string>)?.lanHost).toBe("Lobster.local");
+
+    await started.stop();
+  });
 });

extensions/bonjour/src/advertiser.ts

@@ -1,6 +1,7 @@
 import type { ChildProcess } from "node:child_process";
 import fs from "node:fs";
 import { createRequire } from "node:module";
+import os from "node:os";
 import type { PluginLogger } from "openclaw/plugin-sdk/plugin-entry";
 import { isTruthyEnvValue } from "openclaw/plugin-sdk/runtime-env";
 import { classifyCiaoProcessError, type CiaoProcessErrorClassification } from "./ciao.js";
@@ -160,6 +161,28 @@ function isDisabledByEnv() {
   return false;
 }
 
+function resolveSystemMdnsHostname(): string | null {
+  let raw: string;
+  try {
+    raw = os.hostname();
+  } catch {
+    return null;
+  }
+  const trimmed = raw.trim();
+  if (!trimmed) {
+    return null;
+  }
+  const firstLabel =
+    trimmed
+      .replace(/\.local$/i, "")
+      .split(".")[0]
+      ?.trim() ?? "";
+  if (!/^[A-Za-z0-9](?:[A-Za-z0-9-]{0,61}[A-Za-z0-9])?$/.test(firstLabel)) {
+    return null;
+  }
+  return firstLabel;
+}
+
 function safeServiceName(name: string) {
   const trimmed = name.trim();
   return trimmed.length > 0 ? trimmed : "OpenClaw";
@@ -328,7 +351,8 @@ export async function startGatewayBonjourAdvertiser(
     cleanupUnhandledRejection = deps.registerUnhandledRejectionHandler?.(handleCiaoProcessError);
     cleanupUncaughtException = deps.registerUncaughtExceptionHandler?.(handleCiaoProcessError);
 
-    const hostnameRaw = process.env.OPENCLAW_MDNS_HOSTNAME?.trim() || "openclaw";
+    const hostnameRaw =
+      process.env.OPENCLAW_MDNS_HOSTNAME?.trim() || resolveSystemMdnsHostname() || "openclaw";
     const hostname =
       hostnameRaw
         .replace(/\.local$/i, "")