From 9b645f0e537011a0efbf1ac11dc94a8fa26ff1e3 Mon Sep 17 00:00:00 2001
From: Bohdan Triapitsyn <artmore@protonmail.com>
Date: Mon, 13 Jul 2026 01:29:35 +0300
Subject: [PATCH] perf: fast relay connect on mobile and desktop + connect
 splash + edit-safe instances
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Relay connect used to serialize a dead LAN probe (up to 8s per stale address
on mobile, 2-4s on desktop) in front of the relay attempt, then paid a second
WebSocket connect + E2EE handshake because the probe tunnel was thrown away.

- mobile probeConnectionCandidates: race the relay probe against the direct
  chain with a 1.5s direct headstart; a live LAN still wins, a dead one no
  longer delays startup
- relay probes adopt their tunnel as the runtime tunnel (adoptRelayTunnel)
  instead of dialing a fresh one — applies to auto-connect, pairing redeem,
  password login, and the desktop host switcher's relay fallback
- relay probe drops the /health round-trip: the E2EE handshake already proves
  the server identity, /auth/session alone proves liveness and auth
- desktop restoreDesktopRelayRuntime: same headstart race; a late direct
  success hot-switches back (stable runtimeKey); startup probe now passes
  expectedServerId so a re-leased LAN address never sees the token
- launch splash shows 'Connecting to device: <label>' with animated dots
  under the (still centered) logo, translated in all locales
- editing a saved instance no longer rebuilds it from the URL field alone:
  the id is passed through, relay/https candidates are preserved, and a
  token-key change migrates the Keychain token instead of orphaning it
---
 packages/ui/src/apps/MobileApp.tsx            |  26 +-
 packages/ui/src/apps/mobileConnections.ts     | 312 +++++++++++++-----
 .../desktop/DesktopHostSwitcher.tsx           |  17 +-
 packages/ui/src/lib/desktopHosts.ts           |  16 +-
 packages/ui/src/lib/desktopRelayRestore.ts    |  82 +++--
 packages/ui/src/lib/i18n/messages/en.ts       |   1 +
 packages/ui/src/lib/i18n/messages/es.ts       |   1 +
 packages/ui/src/lib/i18n/messages/fr.ts       |   1 +
 packages/ui/src/lib/i18n/messages/ja.ts       |   1 +
 packages/ui/src/lib/i18n/messages/ko.ts       |   1 +
 packages/ui/src/lib/i18n/messages/pl.ts       |   1 +
 packages/ui/src/lib/i18n/messages/pt-BR.ts    |   1 +
 packages/ui/src/lib/i18n/messages/uk.ts       |   1 +
 packages/ui/src/lib/i18n/messages/zh-CN.ts    |   1 +
 packages/ui/src/lib/i18n/messages/zh-TW.ts    |   1 +
 packages/ui/src/lib/relay/runtime-tunnel.ts   |  13 +
 16 files changed, 372 insertions(+), 104 deletions(-)

diff --git a/packages/ui/src/apps/MobileApp.tsx b/packages/ui/src/apps/MobileApp.tsx
index bc67b397..4e377934 100644
--- a/packages/ui/src/apps/MobileApp.tsx
+++ b/packages/ui/src/apps/MobileApp.tsx
@@ -57,10 +57,11 @@ import { SyncProvider, useSession, useSessionMessages } from '@/sync/sync-contex
 import { SyncAppEffects } from './AppEffects';
 import { MobileChangesSurface } from './MobileChangesSurface';
 import { MobileFilesSurface } from './MobileFilesSurface';
+import { BusyDots } from '@/components/chat/message/parts/BusyDots';
 import { MobileSessionsSheet } from './MobileSessionsSheet';
 import { MobileSurfaceShell } from './MobileSurfaceShell';
 import { DedicatedMobileAppProvider, type MobileAppActions } from './mobileAppContext';
-import { autoConnectLastInstance, connectionDisplayUrl, isActiveRuntimeConnection, reprobeActiveConnection, useMobileConnection } from './mobileConnections';
+import { autoConnectLastInstance, connectionDisplayUrl, getAutoConnectTargetLabel, isActiveRuntimeConnection, reprobeActiveConnection, useMobileConnection } from './mobileConnections';
 import { isRelayModeActive } from '@/lib/relay/runtime-tunnel';
 import { isQrScanSupported, parseConnectionPayload, scanConnectionQr } from './mobileQrScan';
 import { reconnectAppForTransportSwitch, resetAppForRuntimeEndpointChange } from './runtimeEndpointReset';
@@ -981,10 +982,13 @@ const MobileInstancesSurface: React.FC<{
 
   const saveInstance = React.useCallback((event: React.FormEvent) => {
     event.preventDefault();
-    void saveConnection({ url, label, clientToken }).then((saved) => {
+    // The id is what makes this an EDIT: saveConnection uses it to preserve the
+    // existing relay/https candidates (and the Keychain token they key) instead
+    // of rebuilding the instance from the single URL field.
+    void saveConnection({ id: editingId ?? undefined, url, label, clientToken }).then((saved) => {
       if (saved) resetForm();
     });
-  }, [clientToken, label, resetForm, saveConnection, url]);
+  }, [clientToken, editingId, label, resetForm, saveConnection, url]);
 
   // Scan a pairing QR into the add/edit form fields (does not change edit mode, so
   // the form-reset effect doesn't wipe the scanned values). The user reviews + saves.
@@ -2688,6 +2692,9 @@ export function MobileApp({ apis }: MobileAppProps) {
   // splash so we don't flash the connect screen; 'done' means we either connected or
   // exhausted the attempt (then the connect screen shows).
   const [autoConnectPhase, setAutoConnectPhase] = React.useState<'pending' | 'attempting' | 'done'>('pending');
+  // The instance the splash says we are connecting to. Read once on mount —
+  // auto-connect targets the most-recent saved connection from the same list.
+  const autoConnectLabel = React.useMemo(() => getAutoConnectTargetLabel(), []);
   // Bumped to force a re-render (and thus a fresh `sdk` prop for SyncProvider)
   // after a same-device transport swap — reconnects the sync layer in place with
   // no remount. The value itself is unused; only the re-render matters.
@@ -3052,8 +3059,19 @@ export function MobileApp({ apis }: MobileAppProps) {
     // (no saved instance, unreachable, or needs re-login).
     if (autoConnectPhase !== 'done') {
       return (
-        <main className="flex min-h-dvh items-center justify-center bg-background text-foreground">
+        <main className="relative flex min-h-dvh items-center justify-center bg-background text-foreground">
           <OpenChamberLogo width={120} height={120} isAnimated />
+          {/* Absolutely positioned below the (still perfectly centered) logo so
+              the text never pushes it up. 50% + half the 120px logo + a gap. */}
+          {autoConnectLabel ? (
+            <div className="absolute inset-x-0 top-[calc(50%+84px)] flex flex-col items-center gap-0.5 px-6 text-center">
+              <p className="typography-small text-muted-foreground">{t('mobile.connect.splash.connectingTo')}</p>
+              <p className="typography-small text-foreground">
+                {autoConnectLabel}
+                <BusyDots />
+              </p>
+            </div>
+          ) : null}
         </main>
       );
     }
diff --git a/packages/ui/src/apps/mobileConnections.ts b/packages/ui/src/apps/mobileConnections.ts
index 9ed852da..697acf9a 100644
--- a/packages/ui/src/apps/mobileConnections.ts
+++ b/packages/ui/src/apps/mobileConnections.ts
@@ -21,7 +21,7 @@ import React from 'react';
 import { useI18n } from '@/lib/i18n';
 import type { PairingConnectionPayload, PairingEndpointCandidate } from '@/lib/connectionPayload';
 import { isCapacitorApp } from '@/lib/platform';
-import { isRelayModeActive } from '@/lib/relay/runtime-tunnel';
+import { adoptRelayTunnel, isRelayModeActive } from '@/lib/relay/runtime-tunnel';
 import { createRelayTunnelClient } from '@/lib/relay/tunnel-client';
 import { runtimeFetch } from '@/lib/runtime-fetch';
 import { getRuntimeApiBaseUrl, getRuntimeKey, switchRuntimeEndpoint } from '@/lib/runtime-switch';
@@ -406,60 +406,87 @@ const RELAY_CONNECT_TIMEOUT_MS = 15_000;
 
 type RelayProbeOutcome = 'ok' | 'needs-login' | 'auth-failed' | 'unreachable';
 
-// Probe /health + /auth/session through a short-lived tunnel — the relay
-// counterpart of the direct flow's pre-switch reachability/auth probe. The
-// throwaway client is always closed; the long-lived runtime tunnel is created
-// by switchRuntimeEndpoint afterwards. Cookies never ride the tunnel, so the
-// cookie-only-session special case from the direct flow does not apply here.
+type RelayProbeResult = {
+  outcome: RelayProbeOutcome;
+  // The live tunnel on 'ok' when the caller asked to keep it (adopted as the
+  // runtime tunnel by switchToTransport, saving a second connect+handshake).
+  tunnel?: ReturnType<typeof createRelayTunnelClient>;
+};
+
+// Probe /auth/session through a tunnel — the relay counterpart of the direct
+// flow's pre-switch reachability/auth probe. No /health round-trip: the E2EE
+// handshake already proves the host's identity (only the paired server owns
+// the private key for the pinned hostEncPubJwk), and /auth/session proves both
+// liveness and token validity in one request. Cookies never ride the tunnel,
+// so the cookie-only-session special case from the direct flow does not apply.
+// With `keepTunnel`, an 'ok' result RETURNS the open tunnel (caller owns it);
+// every other path closes it.
 const probeRelaySession = async (
   relay: MobileRelayConfig,
   token?: string,
   grant?: string,
   timeoutMs: number = RELAY_CONNECT_TIMEOUT_MS,
-): Promise<RelayProbeOutcome> => {
+  options?: { keepTunnel?: boolean },
+): Promise<RelayProbeResult> => {
   const tunnel = createRelayTunnelClient({
     relayUrl: relay.relayUrl,
     serverId: relay.serverId,
     hostEncPubJwk: relay.hostEncPubJwk,
     ...(grant ? { grant } : {}),
   });
+  const finish = (outcome: RelayProbeOutcome): RelayProbeResult => {
+    if (outcome === 'ok' && options?.keepTunnel) return { outcome, tunnel };
+    tunnel.close();
+    return { outcome };
+  };
   try {
     const headers = token ? { Authorization: `Bearer ${token}` } : undefined;
-    const health = await raceWithTimeout(timeoutMs, tunnel.fetch('/health', { headers }).catch(() => null));
-    logConnect('relay:health', { ok: health?.ok === true, status: health?.status ?? null });
-    if (!health?.ok) return 'unreachable';
     const session = await raceWithTimeout(timeoutMs, tunnel.fetch('/auth/session', { headers }).catch(() => null));
     logConnect('relay:session', { ok: session?.ok === true, status: session?.status ?? null, hasToken: Boolean(token) });
-    if (!session) return 'unreachable';
-    if (session.status === 401) return token ? 'auth-failed' : 'needs-login';
-    if (!session.ok && session.status !== 404) return 'auth-failed';
+    if (!session) return finish('unreachable');
+    if (session.status === 401) return finish(token ? 'auth-failed' : 'needs-login');
+    if (!session.ok && session.status !== 404) return finish('auth-failed');
     const status = await readSessionStatus(session);
     if (status && status.disabled !== true && status.authenticated === false) {
-      return token ? 'auth-failed' : 'needs-login';
+      return finish(token ? 'auth-failed' : 'needs-login');
     }
-    return 'ok';
-  } finally {
+    return finish('ok');
+  } catch (error) {
     tunnel.close();
+    throw error;
   }
 };
 
-const switchToRelayRuntime = (relay: MobileRelayConfig, clientToken: string | null, grant?: string, runtimeKey?: string): void => {
+const switchToRelayRuntime = (
+  relay: MobileRelayConfig,
+  clientToken: string | null,
+  grant?: string,
+  runtimeKey?: string,
+  liveTunnel?: ReturnType<typeof createRelayTunnelClient>,
+): void => {
   // Relay mode has no network base URL: runtimeFetch intercepts runtime paths on
   // the current window origin and rides the E2EE tunnel, so the window origin is
   // the correct virtual API base. The runtime key carries the real device
   // identity (stable across a device's transports so LAN⇄relay is not treated
   // as an instance switch).
   const apiBaseUrl = typeof window !== 'undefined' ? window.location.origin : '';
+  const descriptor = {
+    relayUrl: relay.relayUrl,
+    serverId: relay.serverId,
+    hostEncPubJwk: relay.hostEncPubJwk,
+    ...(grant ? { grant } : {}),
+  };
+  // Adopt the probe/redeem tunnel as the runtime tunnel BEFORE the switch: the
+  // activate call inside switchRuntimeEndpoint sees an equal descriptor and
+  // reuses it, skipping a second WebSocket connect + E2EE handshake.
+  if (liveTunnel) {
+    adoptRelayTunnel(descriptor, liveTunnel);
+  }
   switchRuntimeEndpoint({
     apiBaseUrl,
     clientToken,
     runtimeKey: runtimeKey ?? relayConnectionRuntimeKey(relay),
-    relay: {
-      relayUrl: relay.relayUrl,
-      serverId: relay.serverId,
-      hostEncPubJwk: relay.hostEncPubJwk,
-      ...(grant ? { grant } : {}),
-    },
+    relay: descriptor,
   });
 };
 
@@ -712,22 +739,33 @@ export const deleteMobileConnection = async (id: string): Promise<MobileSavedCon
   return next;
 };
 
-// The transport a connect/reconnect settled on.
+// The transport a connect/reconnect settled on. A relay transport MAY carry
+// the already-open probe tunnel; switchToTransport adopts it as the runtime
+// tunnel instead of dialing a fresh one.
 type ChosenTransport =
   | { kind: 'direct'; url: string }
-  | { kind: 'relay'; relay: MobileRelayConfig };
+  | { kind: 'relay'; relay: MobileRelayConfig; tunnel?: ReturnType<typeof createRelayTunnelClient> };
 
 type ProbeResult =
   | { status: 'ok'; transport: ChosenTransport }
   | { status: 'needs-login' }
   | { status: 'unreachable' };
 
-// Probe a saved device's candidates IN ORDER with its bearer token and return
-// the first transport that is both reachable AND accepts the token. This is the
-// heart of "one device, many transports": at home the LAN candidate answers; away
-// it is unreachable so we fall through to relay — no re-pairing. An explicit auth
-// rejection (401 / authenticated:false) applies to every transport (same token),
-// so it short-circuits to needs-login; a merely unreachable candidate is skipped.
+// How long the direct (LAN/tunnel) candidates keep the track to themselves
+// before the relay probe starts. At home a live LAN answers well inside this
+// window, so nothing changes there; with a dead/stale LAN candidate the relay
+// probe is already mid-flight instead of queued behind the full direct timeout
+// (which alone cost up to MOBILE_CONNECT_TIMEOUT_MS per stale address).
+const RELAY_RACE_HEADSTART_MS = 1_500;
+
+// Probe a saved device's candidates and return the first transport that is both
+// reachable AND accepts the token. This is the heart of "one device, many
+// transports": at home the LAN candidate answers; away it is unreachable so we
+// fall through to relay — no re-pairing. Direct candidates are probed in order
+// and keep priority; the relay probe races them after a short headstart instead
+// of waiting for every direct timeout. An explicit auth rejection (401 /
+// authenticated:false) applies to every transport (same token), so it
+// short-circuits to needs-login; a merely unreachable candidate is skipped.
 const probeConnectionCandidates = async (
   candidates: MobileTransportCandidate[],
   token: string | undefined,
@@ -740,40 +778,120 @@ const probeConnectionCandidates = async (
   // now belong to a different machine. Older servers omit serverId from /health;
   // the gate only rejects an explicit mismatch (matching today's behavior otherwise).
   const expectedServerId = relayCandidateOf({ candidates })?.serverId ?? null;
-  for (const candidate of candidates) {
-    if (candidate.kind === 'relay') {
-      const outcome = await probeRelaySession(candidate.relay, token, undefined, options?.fast ? MOBILE_FAST_PROBE_TIMEOUT_MS : undefined);
-      if (outcome === 'ok') return { status: 'ok', transport: { kind: 'relay', relay: candidate.relay } };
-      if (outcome === 'needs-login' || outcome === 'auth-failed') return { status: 'needs-login' };
-      continue; // unreachable → try the next candidate
-    }
-    const url = normalizeConnectionUrl(candidate.url) || candidate.url;
-    const headers = token ? { Authorization: `Bearer ${token}` } : undefined;
-    // /health is unauthenticated by design — never send the bearer token to an
-    // address whose identity has not been checked yet.
-    const health = await requestWithTimeout(`${url}/health`, { method: 'GET' }, requestOptions);
-    if (!health?.ok) continue;
-    if (expectedServerId) {
-      const payload = await health.json().catch(() => null);
-      const reported = payload && typeof payload === 'object' ? (payload as Record<string, unknown>).serverId : null;
-      if (typeof reported === 'string' && reported && reported !== expectedServerId) {
-        logConnect('probe:server-id-mismatch', { url });
-        continue;
+  const relayCandidate = candidates.find((c): c is Extract<MobileTransportCandidate, { kind: 'relay' }> => c.kind === 'relay') ?? null;
+  const directList = candidates.filter((c): c is Extract<MobileTransportCandidate, { kind: 'direct' }> => c.kind === 'direct');
+
+  const probeDirectChain = async (): Promise<ProbeResult> => {
+    for (const candidate of directList) {
+      const url = normalizeConnectionUrl(candidate.url) || candidate.url;
+      const headers = token ? { Authorization: `Bearer ${token}` } : undefined;
+      // /health is unauthenticated by design — never send the bearer token to an
+      // address whose identity has not been checked yet.
+      const health = await requestWithTimeout(`${url}/health`, { method: 'GET' }, requestOptions);
+      if (!health?.ok) continue;
+      if (expectedServerId) {
+        const payload = await health.json().catch(() => null);
+        const reported = payload && typeof payload === 'object' ? (payload as Record<string, unknown>).serverId : null;
+        if (typeof reported === 'string' && reported && reported !== expectedServerId) {
+          logConnect('probe:server-id-mismatch', { url });
+          continue;
+        }
       }
+      const session = await requestWithTimeout(`${url}/auth/session`, { method: 'GET', credentials: 'include', headers }, requestOptions);
+      if (session?.status === 401) return { status: 'needs-login' };
+      if (!session || (!session.ok && session.status !== 404)) continue;
+      const status = await readSessionStatus(session);
+      if (status && status.disabled !== true && status.authenticated === false) return { status: 'needs-login' };
+      // A cookie-only native session (authenticated, but not a `client` bearer scope
+      // and not auth-disabled) is not enough — the native runtime transport needs a
+      // bearer token, so fall through to the password flow to mint one.
+      const authDisabled = status?.disabled === true;
+      if (!token && isCapacitorApp() && !authDisabled && status?.scope !== 'client') return { status: 'needs-login' };
+      return { status: 'ok', transport: { kind: 'direct', url } };
     }
-    const session = await requestWithTimeout(`${url}/auth/session`, { method: 'GET', credentials: 'include', headers }, requestOptions);
-    if (session?.status === 401) return { status: 'needs-login' };
-    if (!session || (!session.ok && session.status !== 404)) continue;
-    const status = await readSessionStatus(session);
-    if (status && status.disabled !== true && status.authenticated === false) return { status: 'needs-login' };
-    // A cookie-only native session (authenticated, but not a `client` bearer scope
-    // and not auth-disabled) is not enough — the native runtime transport needs a
-    // bearer token, so fall through to the password flow to mint one.
-    const authDisabled = status?.disabled === true;
-    if (!token && isCapacitorApp() && !authDisabled && status?.scope !== 'client') return { status: 'needs-login' };
-    return { status: 'ok', transport: { kind: 'direct', url } };
-  }
-  return { status: 'unreachable' };
+    return { status: 'unreachable' };
+  };
+
+  const probeRelay = async (): Promise<ProbeResult> => {
+    if (!relayCandidate) return { status: 'unreachable' };
+    // keepTunnel: an 'ok' probe hands its live tunnel to switchToTransport,
+    // which adopts it as the runtime tunnel — no second connect + handshake.
+    const { outcome, tunnel } = await probeRelaySession(
+      relayCandidate.relay,
+      token,
+      undefined,
+      options?.fast ? MOBILE_FAST_PROBE_TIMEOUT_MS : undefined,
+      { keepTunnel: true },
+    );
+    if (outcome === 'ok') return { status: 'ok', transport: { kind: 'relay', relay: relayCandidate.relay, tunnel } };
+    if (outcome === 'needs-login' || outcome === 'auth-failed') return { status: 'needs-login' };
+    return { status: 'unreachable' };
+  };
+
+  if (!relayCandidate) return probeDirectChain();
+  if (directList.length === 0) return probeRelay();
+
+  // Race: direct keeps its priority via the headstart; the loser's work is
+  // discarded (an unused relay tunnel is closed, a late direct success is
+  // reconciled later by reprobe/candidate-refresh which already prefer direct).
+  return new Promise<ProbeResult>((resolve) => {
+    let settled = false;
+    let relayCancelled = false;
+    let headstartTimer: number | undefined;
+    let directResult: ProbeResult | null = null;
+    let relayResult: ProbeResult | null = null;
+
+    const closeUnusedRelayTunnel = (result: ProbeResult | null) => {
+      if (result?.status === 'ok' && result.transport.kind === 'relay') result.transport.tunnel?.close();
+    };
+    const finish = (result: ProbeResult) => {
+      if (settled) return;
+      settled = true;
+      resolve(result);
+    };
+
+    const startRelayProbe = () => {
+      if (relayCancelled || settled) return;
+      if (headstartTimer !== undefined) {
+        window.clearTimeout(headstartTimer);
+        headstartTimer = undefined;
+      }
+      void probeRelay().then((result) => {
+        relayResult = result;
+        if (settled || relayCancelled) {
+          closeUnusedRelayTunnel(result);
+          return;
+        }
+        if (result.status === 'ok' || result.status === 'needs-login') {
+          finish(result);
+          return;
+        }
+        // Relay unreachable: direct is the only hope left.
+        if (directResult) finish(directResult);
+      });
+    };
+
+    void probeDirectChain().then((result) => {
+      directResult = result;
+      if (settled) return;
+      if (result.status === 'ok' || result.status === 'needs-login') {
+        relayCancelled = true;
+        if (headstartTimer !== undefined) window.clearTimeout(headstartTimer);
+        closeUnusedRelayTunnel(relayResult);
+        finish(result);
+        return;
+      }
+      // Every direct candidate is unreachable: hand over to relay immediately
+      // (skipping any remaining headstart) or settle on its finished verdict.
+      if (relayResult) {
+        finish(relayResult);
+        return;
+      }
+      startRelayProbe();
+    });
+
+    headstartTimer = window.setTimeout(startRelayProbe, RELAY_RACE_HEADSTART_MS);
+  });
 };
 
 // Switch the runtime to a chosen transport. `runtimeKey` is the STABLE device
@@ -786,7 +904,7 @@ const switchToTransport = (
   options?: { runtimeKey?: string; grant?: string },
 ): void => {
   if (transport.kind === 'relay') {
-    switchToRelayRuntime(transport.relay, token, options?.grant, options?.runtimeKey);
+    switchToRelayRuntime(transport.relay, token, options?.grant, options?.runtimeKey, transport.tunnel);
   } else {
     switchRuntimeEndpoint({ apiBaseUrl: transport.url, clientToken: token, runtimeKey: options?.runtimeKey });
   }
@@ -796,6 +914,14 @@ const switchToTransport = (
   scheduleCandidateRefresh();
 };
 
+// The display label of the instance cold-launch auto-connect will try (the
+// most-recently-used saved connection) — shown on the launch splash while the
+// connect races run. Null when there is nothing to auto-connect to.
+export const getAutoConnectTargetLabel = (): string | null => {
+  const candidate = readConnections()[0];
+  return candidate?.label?.trim() ? candidate.label : null;
+};
+
 // Cold-launch auto-connect: silently reconnect to the most-recently-used saved
 // instance so a returning user (and notification deep-links) land straight in the
 // app instead of the connect screen. Probes the device's candidates in order, so
@@ -1255,8 +1381,10 @@ export const useMobileConnection = (onConnected: () => void): UseMobileConnectio
     setError(null);
     beginBusy('pairing');
     const deviceCandidates = pairingCandidatesToMobile(payload.candidates);
-    // A chosen relay transport owns an open tunnel; always close it.
+    // A chosen relay transport owns an open tunnel; close it unless the switch
+    // adopted it as the runtime tunnel.
     let chosen: LiveTransport | null = null;
+    let adopted = false;
     try {
       // 1. Find the first reachable transport across all candidates.
       chosen = await establishLiveTransport(deviceCandidates);
@@ -1313,17 +1441,20 @@ export const useMobileConnection = (onConnected: () => void): UseMobileConnectio
         }
       }
       persistMetadata({ label, candidates: deviceCandidates, clientToken: issuedToken });
+      // A relay transport hands its live redeem tunnel to the runtime (adopted
+      // inside switchToTransport) — closing it here would tear down the runtime.
       switchToTransport(
-        chosen.kind === 'relay' ? { kind: 'relay', relay: chosen.relay } : { kind: 'direct', url: chosen.url },
+        chosen.kind === 'relay' ? { kind: 'relay', relay: chosen.relay, tunnel: chosen.tunnel } : { kind: 'direct', url: chosen.url },
         issuedToken,
         { runtimeKey: secureTokenKeyOf({ candidates: deviceCandidates }) },
       );
+      adopted = chosen.kind === 'relay';
       onConnected();
     } catch (error) {
       console.warn('[mobile-connect] pairing threw', error);
       setError(t('mobile.connect.error.authRequired'));
     } finally {
-      if (chosen?.kind === 'relay') chosen.tunnel.close();
+      if (!adopted && chosen?.kind === 'relay') chosen.tunnel.close();
       endBusy('pairing');
     }
   }, [beginBusy, endBusy, onConnected, persistMetadata, t]);
@@ -1333,8 +1464,10 @@ export const useMobileConnection = (onConnected: () => void): UseMobileConnectio
     setError(null);
     beginBusy('password');
     const { id, label, candidates } = pendingConnection;
-    // A chosen relay transport owns an open tunnel; always close it.
+    // A chosen relay transport owns an open tunnel; close it unless the switch
+    // adopted it as the runtime tunnel.
     let chosen: LiveTransport | null = null;
+    let adopted = false;
     try {
       // Log in over whichever transport is reachable. Relay login rides the
       // tunnel; cookies never cross it, so an issued bearer token is mandatory
@@ -1386,17 +1519,20 @@ export const useMobileConnection = (onConnected: () => void): UseMobileConnectio
       }
       persistMetadata({ id, label, candidates, clientToken: issuedToken });
       setPendingConnection(null);
+      // A relay transport hands its live login tunnel to the runtime (adopted
+      // inside switchToTransport) — closing it here would tear down the runtime.
       switchToTransport(
-        chosen.kind === 'relay' ? { kind: 'relay', relay: chosen.relay } : { kind: 'direct', url: chosen.url },
+        chosen.kind === 'relay' ? { kind: 'relay', relay: chosen.relay, tunnel: chosen.tunnel } : { kind: 'direct', url: chosen.url },
         issuedToken,
         { runtimeKey: secureTokenKeyOf({ candidates }) },
       );
+      adopted = chosen.kind === 'relay';
       onConnected();
     } catch (error) {
       console.warn('[mobile-connect] password threw', error);
       setError(t('mobile.connect.error.passwordFailed'));
     } finally {
-      if (chosen?.kind === 'relay') chosen.tunnel.close();
+      if (!adopted && chosen?.kind === 'relay') chosen.tunnel.close();
       endBusy('password');
     }
   }, [beginBusy, endBusy, onConnected, pendingConnection, persistMetadata, t]);
@@ -1408,16 +1544,44 @@ export const useMobileConnection = (onConnected: () => void): UseMobileConnectio
 
   const saveConnection = React.useCallback(async (input: MobileConnectInput): Promise<MobileSavedConnection | null> => {
     setError(null);
-    const candidates = buildCandidatesFromInput(input);
+    let candidates = buildCandidatesFromInput(input);
+    const existing = input.id ? connectionsRef.current.find((connection) => connection.id === input.id) ?? null : null;
+    if (existing) {
+      // EDIT must never silently drop transports the form does not show. The
+      // form carries one URL, but a paired device also has a relay candidate
+      // (whose identity derives the Keychain token key) and possibly https
+      // tunnel candidates. Same merge policy as the background candidate
+      // refresh: the typed URL replaces the http:// (LAN-class) directs;
+      // https:// directs and the relay candidate are preserved. Dropping the
+      // relay here used to change the token key and orphan the stored token.
+      const inputDirects = candidates.filter((c): c is Extract<MobileTransportCandidate, { kind: 'direct' }> => c.kind === 'direct');
+      const preservedHttps = directCandidates(existing).filter(
+        (c) => c.url.startsWith('https://') && !inputDirects.some((n) => isSameConnectionUrl(n.url, c.url)),
+      );
+      const relay = relayCandidateOf(existing);
+      candidates = [...inputDirects, ...preservedHttps, ...(relay ? [{ kind: 'relay' as const, relay }] : [])];
+    }
     if (candidates.length === 0) {
       setError(t('mobile.connect.error.urlRequired'));
       return null;
     }
     const clientToken = input.clientToken?.trim() || undefined;
     const label = input.label?.trim() || getConnectionLabel(connectionDisplayUrl({ candidates }));
-    // Awaited token write so "Save" truly persisted the secret before returning.
-    if (isCapacitorApp() && clientToken) {
-      await writeSecureToken(secureTokenKeyOf({ candidates }), clientToken);
+    // Awaited token writes so "Save" truly persisted the secret before returning.
+    if (isCapacitorApp()) {
+      const nextKey = secureTokenKeyOf({ candidates });
+      if (clientToken) {
+        await writeSecureToken(nextKey, clientToken);
+      } else if (existing?.hasToken) {
+        // No new token typed but the edit changed the token key (e.g. a
+        // direct-only instance got a new URL): move the stored token to the
+        // new key instead of leaving it stranded under the old one.
+        const previousKey = secureTokenKeyOf(existing);
+        if (previousKey && nextKey && previousKey !== nextKey) {
+          const storedToken = await readSecureToken(previousKey);
+          if (storedToken) await writeSecureToken(nextKey, storedToken);
+        }
+      }
     }
     const next = persistMetadata({ id: input.id, label, candidates, clientToken });
     return next.find((connection) => candidateSetsMatch(connection.candidates, candidates)) ?? null;
diff --git a/packages/ui/src/components/desktop/DesktopHostSwitcher.tsx b/packages/ui/src/components/desktop/DesktopHostSwitcher.tsx
index e70f40cd..cf953a8d 100644
--- a/packages/ui/src/components/desktop/DesktopHostSwitcher.tsx
+++ b/packages/ui/src/components/desktop/DesktopHostSwitcher.tsx
@@ -32,6 +32,8 @@ import {
   type HostProbeResult,
 } from '@/lib/desktopHosts';
 import { scheduleDesktopHostCandidateRefresh } from '@/lib/desktopRelayRestore';
+import { adoptRelayTunnel } from '@/lib/relay/runtime-tunnel';
+import { createRelayTunnelClient } from '@/lib/relay/tunnel-client';
 import { getRuntimeApiBaseUrl, getRuntimeKey, subscribeRuntimeEndpointChanged, switchRuntimeEndpoint } from '@/lib/runtime-switch';
 import {
   desktopSshConnect,
@@ -513,7 +515,13 @@ export function DesktopHostSwitcherDialog({
     // Relay legs ride the E2EE tunnel activated in-renderer via
     // switchRuntimeEndpoint({ relay }); the runtime fetch/socket layers route
     // through the tunnel from the singleton registry.
-    const activateRelay = (relay: NonNullable<DesktopHost['relay']>) => {
+    const activateRelay = (relay: NonNullable<DesktopHost['relay']>, liveTunnel?: ReturnType<typeof createRelayTunnelClient>) => {
+      // Adopt the probe's live tunnel (when it kept one) BEFORE the switch: the
+      // activate call inside switchRuntimeEndpoint sees an equal descriptor and
+      // reuses it — no second WebSocket connect + E2EE handshake.
+      if (liveTunnel) {
+        adoptRelayTunnel({ relayUrl: relay.relayUrl, serverId: relay.serverId, hostEncPubJwk: relay.hostEncPubJwk }, liveTunnel);
+      }
       switchRuntimeEndpoint({
         apiBaseUrl: typeof window !== 'undefined' ? window.location.origin : '',
         clientToken: host.clientToken || null,
@@ -562,11 +570,14 @@ export function DesktopHostSwitcherDialog({
         finalStatus = { status: probe.status, latencyMs: probe.latencyMs };
         if (!isBlockedHostStatus(probe.status)) transport = 'direct';
       }
+      let relayProbeTunnel: ReturnType<typeof createRelayTunnelClient> | undefined;
       if (!transport && host.relay) {
-        const probe = await probeRelayDesktopHost(host.relay).catch((): HostProbeResult => ({ status: 'unreachable', latencyMs: 0 }));
+        const probe = await probeRelayDesktopHost(host.relay, { keepTunnel: true })
+          .catch((): HostProbeResult => ({ status: 'unreachable', latencyMs: 0 }));
         if (probe.status === 'ok') {
           finalStatus = { status: probe.status, latencyMs: probe.latencyMs, via: 'relay' };
           transport = 'relay';
+          relayProbeTunnel = 'tunnel' in probe ? probe.tunnel : undefined;
         }
       }
       setStatusById((prev) => ({ ...prev, [host.id]: finalStatus }));
@@ -577,7 +588,7 @@ export function DesktopHostSwitcherDialog({
         return;
       }
       if (transport === 'relay' && host.relay) {
-        activateRelay(host.relay);
+        activateRelay(host.relay, relayProbeTunnel);
       } else {
         switchRuntimeEndpoint({ apiBaseUrl: apiOrigin, clientToken: clientToken || null, requestHeaders: host.requestHeaders || null, runtimeKey: runtimeKeyForHost(host) });
       }
diff --git a/packages/ui/src/lib/desktopHosts.ts b/packages/ui/src/lib/desktopHosts.ts
index 353fa18d..d89f5cbb 100644
--- a/packages/ui/src/lib/desktopHosts.ts
+++ b/packages/ui/src/lib/desktopHosts.ts
@@ -299,13 +299,20 @@ const RELAY_PROBE_TIMEOUT_MS = 8_000;
  * leaves the tunnel in `connecting` forever — the probe must report
  * unreachable instead of hanging every status/switch flow with it.
  */
-export const probeRelayDesktopHost = async (relay: DesktopHostRelay): Promise<HostProbeResult> => {
+export const probeRelayDesktopHost = async (
+  relay: DesktopHostRelay,
+  // With `keepTunnel`, an 'ok' probe RETURNS its live tunnel (the caller owns
+  // it — typically adopting it as the runtime tunnel, skipping a second
+  // WebSocket connect + E2EE handshake); every other outcome closes it.
+  options?: { keepTunnel?: boolean },
+): Promise<HostProbeResult & { tunnel?: ReturnType<typeof createRelayTunnelClient> }> => {
   const tunnel = createRelayTunnelClient({
     relayUrl: relay.relayUrl,
     serverId: relay.serverId,
     hostEncPubJwk: relay.hostEncPubJwk,
   });
   const startedAt = Date.now();
+  let keep = false;
   try {
     const response = await Promise.race([
       tunnel.fetch('/health'),
@@ -316,12 +323,13 @@ export const probeRelayDesktopHost = async (relay: DesktopHostRelay): Promise<Ho
         }
       }),
     ]);
-    if (!response) return { status: 'unreachable', latencyMs: 0 };
-    return { status: response.ok ? 'ok' : 'unreachable', latencyMs: Math.max(0, Date.now() - startedAt) };
+    if (!response?.ok) return { status: 'unreachable', latencyMs: 0 };
+    keep = options?.keepTunnel === true;
+    return { status: 'ok', latencyMs: Math.max(0, Date.now() - startedAt), ...(keep ? { tunnel } : {}) };
   } catch {
     return { status: 'unreachable', latencyMs: 0 };
   } finally {
-    tunnel.close();
+    if (!keep) tunnel.close();
   }
 };
 
diff --git a/packages/ui/src/lib/desktopRelayRestore.ts b/packages/ui/src/lib/desktopRelayRestore.ts
index 3b92effa..7cf99e0f 100644
--- a/packages/ui/src/lib/desktopRelayRestore.ts
+++ b/packages/ui/src/lib/desktopRelayRestore.ts
@@ -6,6 +6,11 @@ import { getRuntimeKey, switchRuntimeEndpoint } from '@/lib/runtime-switch';
 // Let the post-switch bootstrap traffic settle before the background refresh.
 const CANDIDATE_REFRESH_DELAY_MS = 5_000;
 
+// How long the stored direct address keeps startup to itself before the relay
+// takes over. A live LAN probe answers well inside this window; a dead one no
+// longer stalls startup for the probe's full timeout.
+const DIRECT_PROBE_HEADSTART_MS = 1_500;
+
 let candidateRefreshInFlight = false;
 
 /**
@@ -120,28 +125,67 @@ export const restoreDesktopRelayRuntime = async (targetHostId?: string): Promise
   const runtimeKey = `host:${host.id}`;
   if (getRuntimeKey() === runtimeKey) return;
 
+  const switchToDirect = (url: string) => {
+    switchRuntimeEndpoint({
+      apiBaseUrl: url,
+      clientToken: host.clientToken || null,
+      requestHeaders: host.requestHeaders || null,
+      runtimeKey,
+    });
+  };
+  const switchToRelay = () => {
+    switchRuntimeEndpoint({
+      apiBaseUrl: typeof window !== 'undefined' ? window.location.origin : '',
+      clientToken: host.clientToken || null,
+      runtimeKey,
+      relay: host.relay ?? undefined,
+    });
+    // On the relay because the stored direct address did not answer (yet) —
+    // ask the server for its current LAN address in the background and
+    // hot-switch back to direct if it simply moved (DHCP re-lease).
+    scheduleDesktopHostCandidateRefresh(host.id);
+  };
+
   const directUrl = host.apiUrl ? normalizeHostUrl(getDesktopHostApiUrl(host)) : null;
-  if (directUrl) {
-    const probe = await desktopHostProbe(directUrl, { clientToken: host.clientToken || null, requestHeaders: host.requestHeaders || null })
-      .catch(() => ({ status: 'unreachable' as const, latencyMs: 0 }));
-    if (probe.status !== 'unreachable' && probe.status !== 'wrong-service' && probe.status !== 'incompatible') {
-      switchRuntimeEndpoint({
-        apiBaseUrl: directUrl,
-        clientToken: host.clientToken || null,
-        requestHeaders: host.requestHeaders || null,
-        runtimeKey,
-      });
+  if (!directUrl) {
+    switchToRelay();
+    return;
+  }
+
+  // Race the direct probe against a short headstart instead of serializing the
+  // full probe timeout in front of the relay fallback: a live LAN answers well
+  // inside the window (direct keeps priority); a dead one no longer delays
+  // startup — the relay takes over and a late direct success hot-switches back
+  // (stable runtimeKey → transport-only swap, same as the candidate refresh).
+  const probeOk = (probe: { status: string }) =>
+    probe.status !== 'unreachable' && probe.status !== 'wrong-service' && probe.status !== 'incompatible';
+  const probePromise = desktopHostProbe(directUrl, {
+    clientToken: host.clientToken || null,
+    requestHeaders: host.requestHeaders || null,
+    // Identity gate: a re-leased LAN address may now belong to a different
+    // machine; the probe must not send the token on a serverId mismatch.
+    expectedServerId: host.relay.serverId,
+  }).catch(() => ({ status: 'unreachable' as const, latencyMs: 0 }));
+
+  const winner = await Promise.race([
+    probePromise,
+    new Promise<null>((resolve) => setTimeout(() => resolve(null), DIRECT_PROBE_HEADSTART_MS)),
+  ]);
+  if (winner) {
+    if (probeOk(winner)) {
+      switchToDirect(directUrl);
       return;
     }
+    switchToRelay();
+    return;
   }
-  switchRuntimeEndpoint({
-    apiBaseUrl: typeof window !== 'undefined' ? window.location.origin : '',
-    clientToken: host.clientToken || null,
-    runtimeKey,
-    relay: host.relay,
+
+  // Headstart expired: connect via relay now; adopt the direct transport if the
+  // still-running probe succeeds a moment later.
+  switchToRelay();
+  void probePromise.then((probe) => {
+    if (!probeOk(probe)) return;
+    if (getRuntimeKey() !== runtimeKey) return; // user switched away meanwhile
+    switchToDirect(directUrl);
   });
-  // Landed on the relay because the stored direct address failed — ask the
-  // server for its current LAN address in the background and hot-switch back
-  // to direct if it simply moved (DHCP re-lease).
-  scheduleDesktopHostCandidateRefresh(host.id);
 };
diff --git a/packages/ui/src/lib/i18n/messages/en.ts b/packages/ui/src/lib/i18n/messages/en.ts
index ae4cf7f7..1b251f85 100644
--- a/packages/ui/src/lib/i18n/messages/en.ts
+++ b/packages/ui/src/lib/i18n/messages/en.ts
@@ -62,6 +62,7 @@ export const dict = {
   'mobile.connect.saved.empty': 'No saved connections yet.',
   'mobile.connect.relay.badge': 'via OpenChamber Relay',
   'mobile.connect.error.urlRequired': 'Enter a server URL.',
+  'mobile.connect.splash.connectingTo': 'Connecting to device:',
   'mobile.connect.error.invalidUrl': 'That server URL is not valid.',
   'mobile.connect.error.unreachable': 'Could not reach that OpenChamber server.',
   'mobile.connect.error.authRequired': 'This server needs a password or client token.',
diff --git a/packages/ui/src/lib/i18n/messages/es.ts b/packages/ui/src/lib/i18n/messages/es.ts
index 827608fe..ecf5750b 100644
--- a/packages/ui/src/lib/i18n/messages/es.ts
+++ b/packages/ui/src/lib/i18n/messages/es.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   "mobile.connect.saved.empty": "Aún no hay conexiones guardadas.",
   "mobile.connect.relay.badge": "a través de OpenChamber Relay",
   "mobile.connect.error.urlRequired": "Introduce una URL de servidor.",
+  "mobile.connect.splash.connectingTo": "Conectando al dispositivo:",
   "mobile.connect.error.invalidUrl": "Esa URL de servidor no es válida.",
   "mobile.connect.error.unreachable": "No se pudo conectar con ese servidor de OpenChamber.",
   "mobile.connect.error.authRequired": "Este servidor requiere una contraseña o un token de cliente.",
diff --git a/packages/ui/src/lib/i18n/messages/fr.ts b/packages/ui/src/lib/i18n/messages/fr.ts
index f1641ff5..ddee9d53 100644
--- a/packages/ui/src/lib/i18n/messages/fr.ts
+++ b/packages/ui/src/lib/i18n/messages/fr.ts
@@ -2564,6 +2564,7 @@ export const dict = {
   'mobile.connect.saved.empty': 'Aucune connexion enregistrée pour le moment.',
   'mobile.connect.relay.badge': 'via OpenChamber Relay',
   'mobile.connect.error.urlRequired': 'Saisissez une URL de serveur.',
+  'mobile.connect.splash.connectingTo': 'Connexion à l’appareil :',
   'mobile.connect.error.invalidUrl': 'Cette URL de serveur n\'est pas valide.',
   'mobile.connect.error.unreachable': 'Impossible de joindre ce serveur OpenChamber.',
   'mobile.connect.error.authRequired': 'Ce serveur nécessite un mot de passe ou un jeton client.',
diff --git a/packages/ui/src/lib/i18n/messages/ja.ts b/packages/ui/src/lib/i18n/messages/ja.ts
index c978d69a..50416869 100644
--- a/packages/ui/src/lib/i18n/messages/ja.ts
+++ b/packages/ui/src/lib/i18n/messages/ja.ts
@@ -62,6 +62,7 @@ export const dict: Record<I18nKey, string> = {
   'mobile.connect.saved.empty': '保存された接続はまだありません。',
   'mobile.connect.relay.badge': 'OpenChamber Relay 経由',
   'mobile.connect.error.urlRequired': 'サーバー URL を入力してください。',
+  'mobile.connect.splash.connectingTo': 'デバイスに接続中:',
   'mobile.connect.error.invalidUrl': 'そのサーバー URL は無効です。',
   'mobile.connect.error.unreachable': 'その OpenChamber サーバーに接続できませんでした。',
   'mobile.connect.error.authRequired': 'このサーバーにはパスワードまたはクライアントトークンが必要です。',
diff --git a/packages/ui/src/lib/i18n/messages/ko.ts b/packages/ui/src/lib/i18n/messages/ko.ts
index 544456d9..b11dd011 100644
--- a/packages/ui/src/lib/i18n/messages/ko.ts
+++ b/packages/ui/src/lib/i18n/messages/ko.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   'mobile.connect.saved.empty': '아직 저장된 연결이 없습니다.',
   'mobile.connect.relay.badge': 'OpenChamber Relay 경유',
   'mobile.connect.error.urlRequired': '서버 URL을 입력하세요.',
+  'mobile.connect.splash.connectingTo': '기기에 연결하는 중:',
   'mobile.connect.error.invalidUrl': '유효하지 않은 서버 URL입니다.',
   'mobile.connect.error.unreachable': '해당 OpenChamber 서버에 연결할 수 없습니다.',
   'mobile.connect.error.authRequired': '이 서버에는 비밀번호 또는 클라이언트 토큰이 필요합니다.',
diff --git a/packages/ui/src/lib/i18n/messages/pl.ts b/packages/ui/src/lib/i18n/messages/pl.ts
index b697f9e3..5325b0d9 100644
--- a/packages/ui/src/lib/i18n/messages/pl.ts
+++ b/packages/ui/src/lib/i18n/messages/pl.ts
@@ -64,6 +64,7 @@ export const dict: Record<I18nKey, string> = {
   'mobile.connect.saved.empty': 'Brak zapisanych połączeń.',
   'mobile.connect.relay.badge': 'przez OpenChamber Relay',
   'mobile.connect.error.urlRequired': 'Podaj adres URL serwera.',
+  'mobile.connect.splash.connectingTo': 'Łączenie z urządzeniem:',
   'mobile.connect.error.invalidUrl': 'Ten adres URL serwera jest nieprawidłowy.',
   'mobile.connect.error.unreachable': 'Nie udało się połączyć z tym serwerem OpenChamber.',
   'mobile.connect.error.authRequired': 'Ten serwer wymaga hasła lub tokenu klienta.',
diff --git a/packages/ui/src/lib/i18n/messages/pt-BR.ts b/packages/ui/src/lib/i18n/messages/pt-BR.ts
index 1999e39d..f57b394c 100644
--- a/packages/ui/src/lib/i18n/messages/pt-BR.ts
+++ b/packages/ui/src/lib/i18n/messages/pt-BR.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   "mobile.connect.saved.empty": "Nenhuma conexão salva ainda.",
   "mobile.connect.relay.badge": "via OpenChamber Relay",
   "mobile.connect.error.urlRequired": "Informe a URL de um servidor.",
+  "mobile.connect.splash.connectingTo": "Conectando ao dispositivo:",
   "mobile.connect.error.invalidUrl": "Essa URL de servidor não é válida.",
   "mobile.connect.error.unreachable": "Não foi possível acessar esse servidor OpenChamber.",
   "mobile.connect.error.authRequired": "Este servidor requer uma senha ou token do cliente.",
diff --git a/packages/ui/src/lib/i18n/messages/uk.ts b/packages/ui/src/lib/i18n/messages/uk.ts
index 356588fd..d9ae8a87 100644
--- a/packages/ui/src/lib/i18n/messages/uk.ts
+++ b/packages/ui/src/lib/i18n/messages/uk.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   "mobile.connect.saved.empty": "Збережених підключень ще немає.",
   "mobile.connect.relay.badge": "через OpenChamber Relay",
   "mobile.connect.error.urlRequired": "Введи адресу сервера.",
+  "mobile.connect.splash.connectingTo": "Підключення до пристрою:",
   "mobile.connect.error.invalidUrl": "Ця адреса сервера некоректна.",
   "mobile.connect.error.unreachable": "Не вдалося достукатись до цього OpenChamber сервера.",
   "mobile.connect.error.authRequired": "Цьому серверу потрібен пароль або client token.",
diff --git a/packages/ui/src/lib/i18n/messages/zh-CN.ts b/packages/ui/src/lib/i18n/messages/zh-CN.ts
index 7344183d..928eb16f 100644
--- a/packages/ui/src/lib/i18n/messages/zh-CN.ts
+++ b/packages/ui/src/lib/i18n/messages/zh-CN.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   'mobile.connect.saved.empty': '暂无已保存的连接。',
   'mobile.connect.relay.badge': '通过 OpenChamber Relay 连接',
   'mobile.connect.error.urlRequired': '请输入服务器 URL。',
+  'mobile.connect.splash.connectingTo': '正在连接设备：',
   'mobile.connect.error.invalidUrl': '该服务器 URL 无效。',
   'mobile.connect.error.unreachable': '无法连接到该 OpenChamber 服务器。',
   'mobile.connect.error.authRequired': '该服务器需要密码或客户端令牌。',
diff --git a/packages/ui/src/lib/i18n/messages/zh-TW.ts b/packages/ui/src/lib/i18n/messages/zh-TW.ts
index 4999e2da..e2b99900 100644
--- a/packages/ui/src/lib/i18n/messages/zh-TW.ts
+++ b/packages/ui/src/lib/i18n/messages/zh-TW.ts
@@ -63,6 +63,7 @@ export const dict: Record<I18nKey, string> = {
   'mobile.connect.saved.empty': '尚未儲存任何連線。',
   'mobile.connect.relay.badge': '透過 OpenChamber Relay 連線',
   'mobile.connect.error.urlRequired': '請輸入伺服器網址。',
+  'mobile.connect.splash.connectingTo': '正在連線裝置：',
   'mobile.connect.error.invalidUrl': '該伺服器網址無效。',
   'mobile.connect.error.unreachable': '無法連線至該 OpenChamber 伺服器。',
   'mobile.connect.error.authRequired': '此伺服器需要密碼或用戶端權杖。',
diff --git a/packages/ui/src/lib/relay/runtime-tunnel.ts b/packages/ui/src/lib/relay/runtime-tunnel.ts
index bc5f3778..dc3ce7ed 100644
--- a/packages/ui/src/lib/relay/runtime-tunnel.ts
+++ b/packages/ui/src/lib/relay/runtime-tunnel.ts
@@ -40,6 +40,19 @@ export const activateRelayTunnel = (descriptor: RelayRuntimeDescriptor): RelayTu
   return activeTunnel;
 };
 
+/**
+ * Adopts an ALREADY-OPEN tunnel client (e.g. the connect flow's probe tunnel)
+ * as the active runtime tunnel, so the immediately following
+ * `activateRelayTunnel` with an equal descriptor reuses it instead of paying a
+ * second WebSocket connect + E2EE handshake. Replaces any previous tunnel.
+ */
+export const adoptRelayTunnel = (descriptor: RelayRuntimeDescriptor, client: RelayTunnelClient): void => {
+  if (activeTunnel === client) return;
+  activeTunnel?.close();
+  activeDescriptor = descriptor;
+  activeTunnel = client;
+};
+
 export const deactivateRelayTunnel = (): void => {
   activeTunnel?.close();
   activeTunnel = null;