diff --git a/extensions/remote-control/auth/tokens.ts b/extensions/remote-control/auth/tokens.ts
index e75bdf2..a793257 100644
--- a/extensions/remote-control/auth/tokens.ts
+++ b/extensions/remote-control/auth/tokens.ts
@@ -20,6 +20,29 @@ import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 
+// ---------------------------------------------------------------------------
+// In-memory cache for sync validation (WS upgrade can't await)
+// ---------------------------------------------------------------------------
+
+const _tokenCache = new Set<string>();
+
+function cacheToken(token: string): void {
+  _tokenCache.add(token);
+}
+
+/** Sync bearer validation — checks in-memory cache populated at runtime. */
+export function validateBearerSync(bearer: string): boolean {
+  return _tokenCache.has(bearer);
+}
+
+/** Warm the cache from disk on startup. */
+export async function warmTokenCache(stateDir?: string): Promise<void> {
+  const entries = await loadTokens(stateDir);
+  for (const e of entries) _tokenCache.add(e.token);
+}
+
+// ---------------------------------------------------------------------------
+
 export interface TokenEntry {
   id: string;
   token: string;
@@ -70,6 +93,7 @@ export async function createToken(
   };
   entries.push(entry);
   await saveTokens(entries, stateDir);
+  cacheToken(entry.token);
   return entry;
 }
 
diff --git a/extensions/remote-control/server/server.ts b/extensions/remote-control/server/server.ts
index 115b6d3..9e815fa 100644
--- a/extensions/remote-control/server/server.ts
+++ b/extensions/remote-control/server/server.ts
@@ -34,7 +34,12 @@ import {
   generatePairingToken,
   printPairingQr,
 } from "../auth/pairing.js";
-import { createToken, validateBearer } from "../auth/tokens.js";
+import {
+  createToken,
+  validateBearer,
+  validateBearerSync,
+  warmTokenCache,
+} from "../auth/tokens.js";
 import {
   generateSessionId,
   loadOrCreateToken,
@@ -81,6 +86,7 @@ export async function startServer(
   const clientChangeListeners: Array<() => void> = [];
   const clients = new Set<WsClient>();
   const token = await loadOrCreateToken();
+  await warmTokenCache(); // pre-load multi-tokens into sync cache
 
   // Map of valid session IDs → expiry timestamp (ms since epoch)
   const SESSION_TTL_MS = 86_400_000; // 24 h — matches cookie Max-Age
@@ -112,8 +118,7 @@ export async function startServer(
     const bearer = extractBearer(req);
     if (bearer) {
       if (validateToken(bearer, token)) return true;
-      // async validateBearer checked in asyncHandler for API routes;
-      // for WS upgrade we do a sync fallback: legacy token only here.
+      if (validateBearerSync(bearer)) return true; // multi-token sync cache
     }
 
     return false;