@@ -177,6 +177,7 @@ PASSKEY_ORIGIN=http://192.168.1.244:5003
 1. Check AUTH_SECRET is persistent across restarts
 2. Verify cookies aren't being blocked
 3. Check AUTH_SECURE_COOKIES setting
+4. If accessing from a different site (cross-site, not just cross-origin), note that CORS alone is not sufficient: the auth config in `backend/src/auth/index.ts` sets no `sameSite` override, so better-auth's `SameSite=Lax` default prevents the session cookie from being attached to cross-site requests regardless of `credentials: 'include'` on the client. The app is designed same-origin (`VITE_API_URL` defaults to `''`); cross-site access requires changing `sameSite` to `'none'` with `secure: true`, which is an open question rather than a supported configuration.
 
 ### Passkey Not Working
 
 
@@ -72,7 +72,7 @@ When configured, users can enable push notifications in Settings → Notificatio
 | `PORT` | Server port | `5003` |
 | `HOST` | Server bind address | `0.0.0.0` |
 | `NODE_ENV` | Environment (`development` or `production`) | `development` |
-| `CORS_ORIGIN` | CORS origin for frontend | `http://localhost:5173` |
+| `CORS_ORIGIN` | **Unused / deprecated.** Parsed by `shared/src/config` but consumed nowhere; the effective CORS control is `AUTH_TRUSTED_ORIGINS` (see [Authentication](./authentication.md)). Kept for backwards compatibility — do not rely on it. | `http://localhost:5173` |
 | `LOG_LEVEL` | Logging level | `info` |
 | `DEBUG` | Enable debug logging | `false` |
 
@@ -128,7 +128,7 @@ When configured, users can enable push notifications in Settings → Notificatio
 
 | Variable | Description | Default |
 |----------|-------------|---------|
-| `VITE_API_URL` | Backend API URL for frontend | `http://localhost:5003` |
+| `VITE_API_URL` | Backend API URL for frontend. Defaults to `''` (empty), making the app same-origin — the backend serves the built frontend (`backend/src/index.ts`) and dev uses the Vite `/api` proxy (`frontend/vite.config.ts`). Setting it to a different host puts the app in an **unsupported split-origin mode**; see the open question in `Decisions.md` ("is split-origin deployment supported?") before doing so. | `''` |
 | `VITE_SERVER_PORT` | Backend port hint for frontend | `5003` |
 | `VITE_OPENCODE_PORT` | OpenCode server port hint | `5551` |
 | `VITE_MAX_FILE_SIZE_MB` | File size limit for frontend | `50` |
 
@@ -0,0 +1,92 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { getAuthConfig, DEFAULT_AUTH_CONFIG, listUserPasskeys } from './authInfo'
+
+describe('getAuthConfig', () => {
+  const fetchMock = vi.fn()
+
+  beforeEach(() => {
+    fetchMock.mockReset()
+    vi.stubGlobal('fetch', fetchMock)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('returns the parsed config on success', async () => {
+    const config = {
+      enabledProviders: ['credentials', 'github'],
+      registrationEnabled: true,
+      isFirstUser: false,
+      adminConfigured: true,
+    }
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify(config), { status: 200 }),
+    )
+
+    const result = await getAuthConfig()
+
+    expect(result).toEqual(config)
+
+    const callOptions = fetchMock.mock.calls[0][1]
+    expect(callOptions.credentials).toBe('include')
+  })
+
+  it('falls back to DEFAULT_AUTH_CONFIG on a non-OK response', async () => {
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ error: 'server error' }), { status: 500 }),
+    )
+
+    const result = await getAuthConfig()
+
+    expect(result).toEqual(DEFAULT_AUTH_CONFIG)
+  })
+
+  it('falls back to DEFAULT_AUTH_CONFIG when the network rejects', async () => {
+    fetchMock.mockRejectedValue(new Error('offline'))
+
+    const result = await getAuthConfig()
+
+    expect(result).toEqual(DEFAULT_AUTH_CONFIG)
+  })
+
+  it('defaults isFirstUser to false so the setup flow is not offered when config is unknown', () => {
+    expect(DEFAULT_AUTH_CONFIG.isFirstUser).toBe(false)
+  })
+})
+
+describe('listUserPasskeys', () => {
+  const fetchMock = vi.fn()
+
+  beforeEach(() => {
+    fetchMock.mockReset()
+    vi.stubGlobal('fetch', fetchMock)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('returns the passkey list and sends credentials', async () => {
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify([{ id: 'p1', name: 'laptop' }]), { status: 200 }),
+    )
+
+    const result = await listUserPasskeys()
+
+    expect(result).toEqual([{ id: 'p1', name: 'laptop' }])
+
+    const callOptions = fetchMock.mock.calls[0][1]
+    expect(callOptions.credentials).toBe('include')
+  })
+
+  it('returns an empty array when the request fails', async () => {
+    fetchMock.mockResolvedValue(
+      new Response(JSON.stringify({ error: 'unauthorized' }), { status: 401 }),
+    )
+
+    const result = await listUserPasskeys()
+
+    expect(result).toEqual([])
+  })
+})
@@ -0,0 +1,40 @@
+import { API_BASE_URL } from '@/config'
+import { fetchWrapper } from './fetchWrapper'
+
+export interface AuthConfig {
+  enabledProviders: string[]
+  registrationEnabled: boolean
+  isFirstUser: boolean
+  adminConfigured: boolean
+}
+
+export const DEFAULT_AUTH_CONFIG: AuthConfig = {
+  enabledProviders: ['credentials'],
+  registrationEnabled: true,
+  isFirstUser: false,
+  adminConfigured: false,
+}
+
+export async function getAuthConfig(): Promise<AuthConfig> {
+  try {
+    return await fetchWrapper<AuthConfig>(`${API_BASE_URL}/api/auth-info/config`)
+  } catch {
+    return DEFAULT_AUTH_CONFIG
+  }
+}
+
+export interface Passkey {
+  id: string
+  name?: string
+  credentialID: string
+  createdAt: string
+  deviceType: string
+}
+
+export async function listUserPasskeys(): Promise<Passkey[]> {
+  try {
+    return await fetchWrapper<Passkey[]>(`${API_BASE_URL}/api/auth/passkey/list-user-passkeys`)
+  } catch {
+    return []
+  }
+}
@@ -0,0 +1,113 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { FetchError } from '@opencode-manager/shared'
+import { fetchWrapper } from './fetchWrapper'
+
+describe('fetchWrapper', () => {
+  const fetchMock = vi.fn()
+
+  beforeEach(() => {
+    fetchMock.mockReset()
+    vi.stubGlobal('fetch', fetchMock)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('sends credentials: include on every request', async () => {
+    fetchMock.mockResolvedValue(new Response(JSON.stringify({ ok: true }), { status: 200 }))
+
+    await fetchWrapper('/api/x')
+
+    expect(fetchMock.mock.calls[0][1].credentials).toBe('include')
+  })
+
+  it('keeps credentials: include when the caller passes its own options', async () => {
+    fetchMock.mockResolvedValue(new Response(JSON.stringify({ ok: true }), { status: 200 }))
+
+    await fetchWrapper('/api/x', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: '{}',
+    })
+
+    const init = fetchMock.mock.calls[0][1]
+    expect(init.credentials).toBe('include')
+    expect(init.method).toBe('POST')
+  })
+
+  it('aborts the request when the caller signal aborts', async () => {
+    fetchMock.mockImplementation((_url, init) =>
+      new Promise((_resolve, reject) => {
+        init.signal.addEventListener('abort', () =>
+          reject(new DOMException('Aborted', 'AbortError')),
+        )
+      }),
+    )
+
+    const controller = new AbortController()
+    const promise = fetchWrapper('/api/x', { signal: controller.signal })
+    controller.abort()
+    await expect(promise).rejects.toThrow()
+  })
+
+  it('rejects with a 408 TIMEOUT FetchError when the timeout elapses', async () => {
+    vi.useFakeTimers()
+    fetchMock.mockImplementation((_url, init) => {
+      const signal = init.signal as AbortSignal
+      return new Promise((_resolve, reject) => {
+        if (signal.aborted) {
+          const err = new Error('The operation was aborted')
+          err.name = 'AbortError'
+          reject(err)
+          return
+        }
+        signal.addEventListener('abort', () => {
+          const err = new Error('The operation was aborted')
+          err.name = 'AbortError'
+          reject(err)
+        }, { once: true })
+      })
+    })
+
+    const promise = fetchWrapper('/api/x', { timeout: 100 })
+    vi.advanceTimersByTime(101)
+
+    await expect(promise).rejects.toBeInstanceOf(FetchError)
+    await expect(promise).rejects.toMatchObject({
+      statusCode: 408,
+      code: 'TIMEOUT',
+    })
+
+    vi.useRealTimers()
+  })
+
+  it('rejects with 499 CANCELED when the caller aborts, not 408 TIMEOUT', async () => {
+    fetchMock.mockImplementation((_url, init) => {
+      const signal = init.signal as AbortSignal
+      return new Promise((_resolve, reject) => {
+        if (signal.aborted) {
+          const err = new Error('The operation was aborted')
+          err.name = 'AbortError'
+          reject(err)
+          return
+        }
+        signal.addEventListener('abort', () => {
+          const err = new Error('The operation was aborted')
+          err.name = 'AbortError'
+          reject(err)
+        }, { once: true })
+      })
+    })
+
+    const controller = new AbortController()
+    const promise = fetchWrapper('/api/x', { signal: controller.signal })
+    controller.abort()
+
+    await expect(promise).rejects.toBeInstanceOf(FetchError)
+    await expect(promise).rejects.toMatchObject({
+      statusCode: 499,
+      code: 'CANCELED',
+    })
+  })
+})
@@ -72,12 +72,19 @@ async function fetchWithTimeout(
   url: string,
   options: FetchWrapperOptions = {}
 ): Promise<Response> {
-  const { timeout = 30000, params, ...fetchOptions } = options
+  const { timeout = 30000, params, signal: callerSignal, ...fetchOptions } = options
   const urlObj = buildUrl(url, params)
 
   const controller = new AbortController()
   const timeoutId = timeout > 0 ? setTimeout(() => controller.abort(), timeout) : null
 
+  const abortFromCaller = () => controller.abort()
+  if (callerSignal?.aborted) {
+    controller.abort()
+  } else {
+    callerSignal?.addEventListener('abort', abortFromCaller, { once: true })
+  }
+
   try {
     const response = await fetch(urlObj.toString(), {
       credentials: 'include',
@@ -86,6 +93,7 @@ async function fetchWithTimeout(
     })
 
     if (timeoutId) clearTimeout(timeoutId)
+    if (callerSignal) callerSignal.removeEventListener('abort', abortFromCaller)
 
     if (!response.ok) {
       await handleResponse(response)
@@ -94,7 +102,11 @@ async function fetchWithTimeout(
     return response
   } catch (error) {
     if (timeoutId) clearTimeout(timeoutId)
+    if (callerSignal) callerSignal.removeEventListener('abort', abortFromCaller)
     if (error instanceof Error && error.name === 'AbortError') {
+      if (callerSignal?.aborted) {
+        throw new FetchError('Request canceled', 499, 'CANCELED')
+      }
       throw new FetchError('Request timeout', 408, 'TIMEOUT')
     }
     throw error