diff --git a/README.md b/README.md
index e02e7eb..c6cb7ad 100644
--- a/README.md
+++ b/README.md
@@ -49,8 +49,9 @@ Open `http://localhost:5173`.
 ### 4) Pair with an agent
 
 1. Enter the WebSocket endpoint (default: `ws://127.0.0.1:32123/ws`).
-2. Enter a 6-digit pairing PIN.
-3. After `pairing_result`, the UI switches to chat mode.
+2. If your backend requires `web.accounts.<name>.auth_token` (common for non-loopback binds), set it in the optional `auth_token` field.
+3. Enter a 6-digit pairing PIN.
+4. After `pairing_result`, the UI switches to chat mode.
 
 ## Scripts
 
@@ -101,7 +102,7 @@ Detailed docs:
 
 `localStorage` keys:
 
-- `nullclaw_ui_auth_v1` - endpoint URL, `access_token`, `shared_key`, `expires_at`.
+- `nullclaw_ui_auth_v1` - endpoint URL (may include `?token=` when used), `access_token`, `shared_key`, `expires_at`.
 - `nullclaw_ui_theme` - current theme.
 - `nullclaw_ui_effects` - visual effects toggle.
 
diff --git a/docs/operations.md b/docs/operations.md
index e9e9a77..47377fb 100644
--- a/docs/operations.md
+++ b/docs/operations.md
@@ -24,6 +24,7 @@ Implications:
 
 WebSocket endpoint is currently user-entered in `PairingScreen`.
 Default value: `ws://127.0.0.1:32123/ws`.
+For deployments that enforce `web.accounts.<name>.auth_token`, users can provide the value via the optional `auth_token` field in the pairing form (it is appended as `?token=...` when opening the WebSocket).
 
 To change default endpoint, update initial `url` in `src/lib/components/PairingScreen.svelte`.
 
@@ -31,7 +32,7 @@ To change default endpoint, update initial `url` in `src/lib/components/PairingS
 
 `nullclaw_ui_auth_v1` in local storage includes:
 
-- endpoint URL
+- endpoint URL (may include `token` query param when configured in UI)
 - `access_token`
 - `shared_key` (base64url)
 - `expires_at`
diff --git a/src/lib/components/ConnectionModal.svelte b/src/lib/components/ConnectionModal.svelte
index 858b9e6..9ee05ad 100644
--- a/src/lib/components/ConnectionModal.svelte
+++ b/src/lib/components/ConnectionModal.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
     import type { ClientState } from "$lib/protocol/client.svelte";
+    import { redactWebSocketAuthToken } from "$lib/protocol/ws-url";
 
     interface Props {
         state: ClientState;
@@ -9,6 +10,7 @@
     }
 
     let { state, sessionId, endpointUrl, onClose }: Props = $props();
+    const safeEndpointUrl = $derived(redactWebSocketAuthToken(endpointUrl));
 
     function handleBackdropClick() {
         onClose();
@@ -39,7 +41,7 @@
         <div class="modal-body">
             <div class="info-line">
                 <span class="label">ENDPOINT_URI:</span>
-                <span class="value">{endpointUrl || "UNRESOLVED"}</span>
+                <span class="value">{safeEndpointUrl || "UNRESOLVED"}</span>
             </div>
 
             <div class="info-line">
diff --git a/src/lib/components/PairingScreen.svelte b/src/lib/components/PairingScreen.svelte
index 95a94a6..bf00c30 100644
--- a/src/lib/components/PairingScreen.svelte
+++ b/src/lib/components/PairingScreen.svelte
@@ -2,19 +2,20 @@
   interface Props {
     connecting?: boolean;
     error?: string | null;
-    onConnect: (url: string, code: string) => void;
+    onConnect: (url: string, code: string, authToken?: string) => void;
   }
 
   let { connecting = false, error = null, onConnect }: Props = $props();
 
   let url = $state("ws://127.0.0.1:32123/ws");
+  let authToken = $state("");
   let code = $state("");
 
   function handleSubmit(e: Event) {
     e.preventDefault();
     const trimmed = code.replace(/\s/g, "");
     if (trimmed.length !== 6 || !/^\d{6}$/.test(trimmed)) return;
-    onConnect(url, trimmed);
+    onConnect(url, trimmed, authToken);
   }
 
   function handleCodeInput(e: Event) {
@@ -41,6 +42,17 @@
         />
       </label>
 
+      <label class="field">
+        <span class="label">auth_token (optional):</span>
+        <input
+          type="password"
+          bind:value={authToken}
+          placeholder="required for non-loopback listen"
+          autocomplete="off"
+          disabled={connecting}
+        />
+      </label>
+
       <label class="field auth-field">
         <span class="label">enter_auth_pin:</span>
         <input
diff --git a/src/lib/components/PairingScreen.test.ts b/src/lib/components/PairingScreen.test.ts
index cf852b1..c7368d3 100644
--- a/src/lib/components/PairingScreen.test.ts
+++ b/src/lib/components/PairingScreen.test.ts
@@ -25,7 +25,7 @@ describe('PairingScreen', () => {
     await fireEvent.submit(form as HTMLFormElement);
 
     expect(onConnect).toHaveBeenCalledTimes(1);
-    expect(onConnect).toHaveBeenCalledWith('ws://127.0.0.1:32123/ws', '123456');
+    expect(onConnect).toHaveBeenCalledWith('ws://127.0.0.1:32123/ws', '123456', '');
   });
 
   it('does not submit when code is invalid', async () => {
@@ -46,4 +46,29 @@ describe('PairingScreen', () => {
 
     expect(onConnect).not.toHaveBeenCalled();
   });
+
+  it('passes auth token when provided', async () => {
+    const onConnect = vi.fn();
+    const { getByPlaceholderText, container } = render(PairingScreen, {
+      props: {
+        connecting: false,
+        error: null,
+        onConnect,
+      },
+    });
+
+    const tokenInput = getByPlaceholderText('required for non-loopback listen') as HTMLInputElement;
+    const codeInput = getByPlaceholderText('______') as HTMLInputElement;
+    await fireEvent.input(tokenInput, { target: { value: 'gateway-secret-token' } });
+    await fireEvent.input(codeInput, { target: { value: '123456' } });
+
+    const form = container.querySelector('form');
+    await fireEvent.submit(form as HTMLFormElement);
+
+    expect(onConnect).toHaveBeenCalledWith(
+      'ws://127.0.0.1:32123/ws',
+      '123456',
+      'gateway-secret-token',
+    );
+  });
 });
diff --git a/src/lib/protocol/e2e.ts b/src/lib/protocol/e2e.ts
index d0065d5..ffff2ce 100644
--- a/src/lib/protocol/e2e.ts
+++ b/src/lib/protocol/e2e.ts
@@ -47,11 +47,9 @@ export async function exportPublicKey(key: CryptoKey): Promise<string> {
 
 async function importPublicKey(base64url: string): Promise<CryptoKey> {
   const raw = fromBase64Url(base64url);
-  const rawBuffer: ArrayBuffer =
-    raw.byteOffset === 0 && raw.byteLength === raw.buffer.byteLength
-      ? (raw.buffer as ArrayBuffer)
-      : raw.slice().buffer;
-  return crypto.subtle.importKey('raw', rawBuffer, { name: 'X25519' }, true, []);
+  const keyBytes = new Uint8Array(new ArrayBuffer(raw.byteLength));
+  keyBytes.set(raw);
+  return crypto.subtle.importKey('raw', keyBytes, { name: 'X25519' }, true, []);
 }
 
 export async function deriveSharedKey(
diff --git a/src/lib/protocol/ws-url.test.ts b/src/lib/protocol/ws-url.test.ts
new file mode 100644
index 0000000..e9ae2a9
--- /dev/null
+++ b/src/lib/protocol/ws-url.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, it } from 'vitest';
+import { redactWebSocketAuthToken, withWebSocketAuthToken } from './ws-url';
+
+describe('withWebSocketAuthToken', () => {
+  it('appends token query parameter when missing', () => {
+    const result = withWebSocketAuthToken(
+      'ws://100.69.118.73:32123/ws',
+      'gateway-token',
+    );
+
+    expect(result).toBe('ws://100.69.118.73:32123/ws?token=gateway-token');
+  });
+
+  it('preserves existing token query parameter', () => {
+    const result = withWebSocketAuthToken(
+      'ws://100.69.118.73:32123/ws?token=already-set',
+      'gateway-token',
+    );
+
+    expect(result).toBe('ws://100.69.118.73:32123/ws?token=already-set');
+  });
+
+  it('does not modify url when token is empty', () => {
+    const result = withWebSocketAuthToken('ws://localhost:32123/ws', '   ');
+    expect(result).toBe('ws://localhost:32123/ws');
+  });
+});
+
+describe('redactWebSocketAuthToken', () => {
+  it('redacts token query parameter for diagnostics output', () => {
+    const result = redactWebSocketAuthToken(
+      'wss://host.example/ws?token=super-secret&foo=bar',
+    );
+
+    expect(result).toBe('wss://host.example/ws?token=***&foo=bar');
+  });
+
+  it('returns the original value when token is absent', () => {
+    const result = redactWebSocketAuthToken('wss://host.example/ws?foo=bar');
+    expect(result).toBe('wss://host.example/ws?foo=bar');
+  });
+});
diff --git a/src/lib/protocol/ws-url.ts b/src/lib/protocol/ws-url.ts
new file mode 100644
index 0000000..621f171
--- /dev/null
+++ b/src/lib/protocol/ws-url.ts
@@ -0,0 +1,44 @@
+const TOKEN_QUERY_PARAM = 'token';
+
+export function withWebSocketAuthToken(url: string, authToken?: string): string {
+  const trimmedUrl = url.trim();
+  const trimmedToken = authToken?.trim();
+
+  if (!trimmedToken) {
+    return trimmedUrl;
+  }
+
+  try {
+    const parsed = new URL(trimmedUrl);
+
+    if (parsed.protocol !== 'ws:' && parsed.protocol !== 'wss:') {
+      return trimmedUrl;
+    }
+
+    const existingToken = parsed.searchParams.get(TOKEN_QUERY_PARAM);
+    if (!existingToken) {
+      parsed.searchParams.set(TOKEN_QUERY_PARAM, trimmedToken);
+    }
+
+    return parsed.toString();
+  } catch {
+    return trimmedUrl;
+  }
+}
+
+export function redactWebSocketAuthToken(url?: string): string | undefined {
+  if (!url) return url;
+
+  try {
+    const parsed = new URL(url);
+
+    if (!parsed.searchParams.has(TOKEN_QUERY_PARAM)) {
+      return url;
+    }
+
+    parsed.searchParams.set(TOKEN_QUERY_PARAM, '***');
+    return parsed.toString();
+  } catch {
+    return url;
+  }
+}
diff --git a/src/lib/session/connection-controller.svelte.ts b/src/lib/session/connection-controller.svelte.ts
index f62e177..375dae5 100644
--- a/src/lib/session/connection-controller.svelte.ts
+++ b/src/lib/session/connection-controller.svelte.ts
@@ -11,6 +11,7 @@ import {
   exportPublicKey,
   generateKeyPair,
 } from '$lib/protocol/e2e';
+import { withWebSocketAuthToken } from '$lib/protocol/ws-url';
 
 const DEFAULT_ENDPOINT_URL = 'ws://unknown';
 const PAIRING_TIMEOUT_MS = 10_000;
@@ -123,16 +124,17 @@ export function createConnectionController(sessionId: string) {
     });
   }
 
-  async function connectWithPairing(url: string, code: string): Promise<void> {
+  async function connectWithPairing(url: string, code: string, authToken?: string): Promise<void> {
+    const connectUrl = withWebSocketAuthToken(url, authToken);
     pairingError = null;
     clearStoredAuth();
     client?.disconnect();
     session.clear();
 
-    const newClient = new NullclawClient(url, sessionId);
-    const handlers = attachClientHandlers(newClient, url);
+    const newClient = new NullclawClient(connectUrl, sessionId);
+    const handlers = attachClientHandlers(newClient, connectUrl);
     client = newClient;
-    lastEndpointUrl = url;
+    lastEndpointUrl = connectUrl;
     client.connect();
 
     try {