fix: auto-detect tailnet DNS hint

src/gateway/server.ts

@@ -77,6 +77,7 @@ import {
   pickPrimaryTailnetIPv4,
   pickPrimaryTailnetIPv6,
 } from "../infra/tailnet.js";
+import { getTailnetHostname } from "../infra/tailscale.js";
 import {
   defaultVoiceWakeTriggers,
   loadVoiceWakeConfig,
@@ -89,6 +90,7 @@ import {
 import { logError, logInfo, logWarn } from "../logger.js";
 import { getChildLogger, getResolvedLoggerSettings } from "../logging.js";
 import { setCommandLaneConcurrency } from "../process/command-queue.js";
+import { runExec } from "../process/exec.js";
 import { monitorWebProvider, webAuthExists } from "../providers/web/index.js";
 import { defaultRuntime } from "../runtime.js";
 import { monitorTelegramProvider } from "../telegram/monitor.js";
@@ -174,6 +176,20 @@ function formatBonjourInstanceName(displayName: string) {
   return `${trimmed} (Clawdis)`;
 }
 
+async function resolveTailnetDnsHint(): Promise<string | undefined> {
+  const envRaw = process.env.CLAWDIS_TAILNET_DNS?.trim();
+  const env = envRaw && envRaw.length > 0 ? envRaw.replace(/\.$/, "") : "";
+  if (env) return env;
+
+  const exec: typeof runExec = (command, args) =>
+    runExec(command, args, { timeoutMs: 1500, maxBuffer: 200_000 });
+  try {
+    return await getTailnetHostname(exec);
+  } catch {
+    return undefined;
+  }
+}
+
 type GatewaySessionsDefaults = {
   model: string | null;
   contextTokens: number | null;
@@ -2048,12 +2064,7 @@ export async function startGatewayServer(
         ? sshPortParsed
         : undefined;
 
-    const tailnetDnsEnv = process.env.CLAWDIS_TAILNET_DNS?.trim();
-    const tailnetDns = wideAreaDiscoveryEnabled
-      ? WIDE_AREA_DISCOVERY_DOMAIN
-      : tailnetDnsEnv && tailnetDnsEnv.length > 0
-        ? tailnetDnsEnv
-        : undefined;
+    const tailnetDns = await resolveTailnetDnsHint();
 
     const bonjour = await startGatewayBonjourAdvertiser({
       instanceName: formatBonjourInstanceName(machineDisplayName),

src/infra/tailscale.ts

@@ -1,3 +1,4 @@
+import { existsSync } from "node:fs";
 import chalk from "chalk";
 import { promptYesNo } from "../cli/prompt.js";
 import { danger, info, isVerbose, logVerbose, warn } from "../globals.js";
@@ -7,20 +8,37 @@ import { ensureBinary } from "./binaries.js";
 
 export async function getTailnetHostname(exec: typeof runExec = runExec) {
   // Derive tailnet hostname (or IP fallback) from tailscale status JSON.
-  const { stdout } = await exec("tailscale", ["status", "--json"]);
-  const parsed = stdout ? (JSON.parse(stdout) as Record<string, unknown>) : {};
-  const self =
-    typeof parsed.Self === "object" && parsed.Self !== null
-      ? (parsed.Self as Record<string, unknown>)
-      : undefined;
-  const dns =
-    typeof self?.DNSName === "string" ? (self.DNSName as string) : undefined;
-  const ips = Array.isArray(self?.TailscaleIPs)
-    ? (self.TailscaleIPs as string[])
-    : [];
-  if (dns && dns.length > 0) return dns.replace(/\.$/, "");
-  if (ips.length > 0) return ips[0];
-  throw new Error("Could not determine Tailscale DNS or IP");
+  const candidates = [
+    "tailscale",
+    "/Applications/Tailscale.app/Contents/MacOS/Tailscale",
+  ];
+  let lastError: unknown;
+
+  for (const candidate of candidates) {
+    if (candidate.startsWith("/") && !existsSync(candidate)) continue;
+    try {
+      const { stdout } = await exec(candidate, ["status", "--json"]);
+      const parsed = stdout
+        ? (JSON.parse(stdout) as Record<string, unknown>)
+        : {};
+      const self =
+        typeof parsed.Self === "object" && parsed.Self !== null
+          ? (parsed.Self as Record<string, unknown>)
+          : undefined;
+      const dns =
+        typeof self?.DNSName === "string" ? (self.DNSName as string) : undefined;
+      const ips = Array.isArray(self?.TailscaleIPs)
+        ? (self.TailscaleIPs as string[])
+        : [];
+      if (dns && dns.length > 0) return dns.replace(/\.$/, "");
+      if (ips.length > 0) return ips[0];
+      throw new Error("Could not determine Tailscale DNS or IP");
+    } catch (err) {
+      lastError = err;
+    }
+  }
+
+  throw lastError ?? new Error("Could not determine Tailscale DNS or IP");
 }
 
 export async function ensureGoInstalled(