feat(vector-sync): enable background sync in OAuth mode

Add multi-user background vector synchronization when running in OAuth
mode with ENABLE_OFFLINE_ACCESS=true. Key changes:

Architecture (oauth_sync.py):
- User Manager task polls RefreshTokenStorage for provisioned users
- Per-user scanner tasks fetch documents using OAuth tokens
- Shared processor pool indexes documents from all users

Token Broker improvements:
- Accept client_id/client_secret instead of encryption_key
- Remove redundant token audience pre-validation (Nextcloud validates)
- Add _rewrite_token_endpoint for Docker internal URL routing
- Remove double-decryption (storage handles encryption internally)

Browser OAuth flow fixes:
- Add 'resource' parameter to request Nextcloud-scoped tokens
- Store and retrieve next_url for proper redirect after consent
- Rewrite token endpoint URLs for internal Docker access

Configuration:
- Add vector_sync_user_poll_interval setting (default: 60s)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nextcloud_mcp_server/app.py

@@ -676,6 +676,29 @@ async def setup_oauth_config():
         logger.info(f"OIDC_JWKS_URI override: {jwks_uri} → {jwks_uri_override}")
         jwks_uri = jwks_uri_override
 
+    # Rewrite discovered endpoint URLs from public issuer to internal host
+    # This is needed when OIDC discovery returns public URLs (e.g., http://localhost:8080)
+    # but the server needs to access them via internal docker network (e.g., http://app:80)
+    from urllib.parse import urlparse
+
+    issuer_parsed = urlparse(issuer)
+    nextcloud_parsed = urlparse(nextcloud_host)
+    issuer_base = f"{issuer_parsed.scheme}://{issuer_parsed.netloc}"
+    nextcloud_base = f"{nextcloud_parsed.scheme}://{nextcloud_parsed.netloc}"
+
+    if issuer_base != nextcloud_base:
+        logger.info(f"Rewriting OIDC endpoints: {issuer_base} → {nextcloud_base}")
+
+        def rewrite_url(url: str | None) -> str | None:
+            if url and url.startswith(issuer_base):
+                return url.replace(issuer_base, nextcloud_base, 1)
+            return url
+
+        userinfo_uri = rewrite_url(userinfo_uri) or userinfo_uri
+        jwks_uri = rewrite_url(jwks_uri)
+        introspection_uri = rewrite_url(introspection_uri)
+        registration_endpoint = rewrite_url(registration_endpoint)
+
     logger.info("OIDC endpoints discovered:")
     logger.info(f"  Issuer: {issuer}")
     logger.info(f"  Userinfo: {userinfo_uri}")
@@ -687,8 +710,6 @@ async def setup_oauth_config():
     # Auto-detect provider mode based on issuer
     # External IdP mode: issuer doesn't match Nextcloud host
     # Normalize URLs for comparison (handle port differences like :80 for HTTP)
-    from urllib.parse import urlparse
-
     def normalize_url(url: str) -> str:
         """Normalize URL by removing default ports (80 for HTTP, 443 for HTTPS)."""
         parsed = urlparse(url)
@@ -704,7 +725,16 @@ async def setup_oauth_config():
     issuer_normalized = normalize_url(issuer)
     nextcloud_normalized = normalize_url(nextcloud_host)
 
-    is_external_idp = not issuer_normalized.startswith(nextcloud_normalized)
+    # Use NEXTCLOUD_PUBLIC_ISSUER_URL for IdP detection when set
+    # This handles the case where MCP server accesses Nextcloud via internal URL (http://app:80)
+    # but the issuer in OIDC discovery is the public URL (http://localhost:8080)
+    public_issuer_for_detection = os.getenv("NEXTCLOUD_PUBLIC_ISSUER_URL")
+    if public_issuer_for_detection:
+        comparison_issuer = normalize_url(public_issuer_for_detection)
+    else:
+        comparison_issuer = nextcloud_normalized
+
+    is_external_idp = not issuer_normalized.startswith(comparison_issuer)
 
     if is_external_idp:
         oauth_provider = "external"  # Could be Keycloak, Auth0, Okta, etc.
@@ -716,6 +746,28 @@ async def setup_oauth_config():
         oauth_provider = "nextcloud"
         logger.info("✓ Detected integrated mode (Nextcloud OIDC app)")
 
+        # For integrated mode, rewrite OIDC endpoints to use internal URL
+        # The discovery document returns external URLs (http://localhost:8080)
+        # but the MCP server needs internal URLs (http://app:80) for backend requests
+        if jwks_uri and not os.getenv("OIDC_JWKS_URI"):
+            internal_jwks_uri = f"{nextcloud_host}/apps/oidc/jwks"
+            logger.info(
+                f"  Auto-rewriting JWKS URI for internal access: {jwks_uri} → {internal_jwks_uri}"
+            )
+            jwks_uri = internal_jwks_uri
+        if introspection_uri and not os.getenv("OIDC_INTROSPECTION_URI"):
+            internal_introspection_uri = f"{nextcloud_host}/apps/oidc/introspect"
+            logger.info(
+                f"  Auto-rewriting introspection URI for internal access: {introspection_uri} → {internal_introspection_uri}"
+            )
+            introspection_uri = internal_introspection_uri
+        if userinfo_uri:
+            internal_userinfo_uri = f"{nextcloud_host}/apps/oidc/userinfo"
+            logger.info(
+                f"  Auto-rewriting userinfo URI for internal access: {userinfo_uri} → {internal_userinfo_uri}"
+            )
+            userinfo_uri = internal_userinfo_uri
+
     # Check if offline access (refresh tokens) is enabled
     enable_offline_access = os.getenv("ENABLE_OFFLINE_ACCESS", "false").lower() in (
         "true",
@@ -1234,12 +1286,20 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
                     )
                     break
 
-        # Start background vector sync tasks for BasicAuth mode (ADR-007)
+        # Start background vector sync tasks (ADR-007)
         # Scanner runs at server-level (once), not per-session
         import anyio as anyio_module
 
         settings = get_settings()
-        if not oauth_enabled and settings.vector_sync_enabled:
+
+        # Check if vector sync is enabled and determine the mode
+        enable_offline_access_for_sync = os.getenv(
+            "ENABLE_OFFLINE_ACCESS", "false"
+        ).lower() in ("true", "1", "yes")
+        encryption_key = os.getenv("TOKEN_ENCRYPTION_KEY")
+
+        if settings.vector_sync_enabled and not oauth_enabled:
+            # BasicAuth mode - single user sync
             logger.info("Starting background vector sync tasks for BasicAuth mode")
 
             # Get username from environment
@@ -1334,8 +1394,161 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
                         shutdown_event.set()
                         await client.close()
                         # TaskGroup automatically cancels all tasks on exit
+
+        elif (
+            settings.vector_sync_enabled
+            and oauth_enabled
+            and enable_offline_access_for_sync
+            and refresh_token_storage
+            and encryption_key
+        ):
+            # OAuth mode with offline access - multi-user sync
+            logger.info("Starting background vector sync tasks for OAuth mode")
+
+            from nextcloud_mcp_server.auth.token_broker import TokenBrokerService
+            from nextcloud_mcp_server.vector.oauth_sync import (
+                oauth_processor_task,
+                user_manager_task,
+            )
+
+            # Get OIDC discovery URL (same as used for OAuth setup)
+            discovery_url = os.getenv(
+                "OIDC_DISCOVERY_URL",
+                f"{nextcloud_host}/.well-known/openid-configuration",
+            )
+
+            # Get client credentials from oauth_context (set by setup_oauth_config)
+            # This includes credentials from DCR if dynamic registration was used
+            # Use different variable names to avoid shadowing client_id/client_secret from outer scope
+            oauth_ctx = getattr(app.state, "oauth_context", {})
+            oauth_config = oauth_ctx.get("config", {})
+            sync_client_id = oauth_config.get("client_id")
+            sync_client_secret = oauth_config.get("client_secret")
+
+            if not sync_client_id or not sync_client_secret:
+                logger.error(
+                    "Cannot start OAuth vector sync: client credentials not found in oauth_context"
+                )
+                raise ValueError("OAuth client credentials required for vector sync")
+
+            # Create token broker for background operations
+            # Note: storage handles encryption internally, no key needed here
+            # Client credentials are needed for token refresh operations
+            token_broker = TokenBrokerService(
+                storage=refresh_token_storage,
+                oidc_discovery_url=discovery_url,
+                nextcloud_host=nextcloud_host,
+                client_id=sync_client_id,
+                client_secret=sync_client_secret,
+            )
+
+            # Initialize Qdrant collection before starting background tasks
+            logger.info("Initializing Qdrant collection...")
+            from nextcloud_mcp_server.vector.qdrant_client import get_qdrant_client
+
+            try:
+                await get_qdrant_client()  # Triggers collection creation if needed
+                logger.info("Qdrant collection ready")
+            except Exception as e:
+                logger.error(f"Failed to initialize Qdrant collection: {e}")
+                raise RuntimeError(
+                    f"Cannot start vector sync - Qdrant initialization failed: {e}"
+                ) from e
+
+            # Initialize shared state
+            send_stream, receive_stream = anyio_module.create_memory_object_stream(
+                max_buffer_size=settings.vector_sync_queue_max_size
+            )
+            shutdown_event = anyio_module.Event()
+            scanner_wake_event = anyio_module.Event()
+
+            # User state tracking for user manager
+            user_states: dict = {}
+
+            # Store in app state for access from routes (ADR-007)
+            app.state.document_send_stream = send_stream
+            app.state.document_receive_stream = receive_stream
+            app.state.shutdown_event = shutdown_event
+            app.state.scanner_wake_event = scanner_wake_event
+
+            # Also store in module singleton for FastMCP session lifespans
+            _vector_sync_state.document_send_stream = send_stream
+            _vector_sync_state.document_receive_stream = receive_stream
+            _vector_sync_state.shutdown_event = shutdown_event
+            _vector_sync_state.scanner_wake_event = scanner_wake_event
+            logger.info("Vector sync state stored in module singleton")
+
+            # Also share with browser_app for /app route
+            for route in app.routes:
+                if isinstance(route, Mount) and route.path == "/app":
+                    route.app.state.document_send_stream = send_stream
+                    route.app.state.document_receive_stream = receive_stream
+                    route.app.state.shutdown_event = shutdown_event
+                    route.app.state.scanner_wake_event = scanner_wake_event
+                    logger.info("Vector sync state shared with browser_app for /app")
+                    break
+
+            # Start background tasks using anyio TaskGroup
+            async with anyio_module.create_task_group() as tg:
+                # Start user manager task (supervises per-user scanners)
+                await tg.start(
+                    user_manager_task,
+                    send_stream,
+                    shutdown_event,
+                    scanner_wake_event,
+                    token_broker,
+                    refresh_token_storage,
+                    nextcloud_host,
+                    user_states,
+                    tg,
+                )
+
+                # Start processor pool (each gets a cloned receive stream)
+                for i in range(settings.vector_sync_processor_workers):
+                    await tg.start(
+                        oauth_processor_task,
+                        i,
+                        receive_stream.clone(),
+                        shutdown_event,
+                        token_broker,
+                        nextcloud_host,
+                    )
+
+                logger.info(
+                    f"Background sync tasks started: 1 user manager + "
+                    f"{settings.vector_sync_processor_workers} processors"
+                )
+
+                # Run MCP session manager and yield
+                async with AsyncExitStack() as stack:
+                    await stack.enter_async_context(mcp.session_manager.run())
+                    try:
+                        yield
+                    finally:
+                        # Shutdown signal
+                        logger.info("Shutting down background sync tasks")
+                        shutdown_event.set()
+                        # Close token broker HTTP client
+                        if token_broker._http_client:
+                            await token_broker._http_client.aclose()
+                        # TaskGroup automatically cancels all tasks on exit
         else:
             # No vector sync - just run MCP session manager
+            if settings.vector_sync_enabled:
+                # Log why vector sync is not starting
+                if oauth_enabled and not enable_offline_access_for_sync:
+                    logger.warning(
+                        "Vector sync enabled but ENABLE_OFFLINE_ACCESS=false - "
+                        "vector sync requires offline access in OAuth mode"
+                    )
+                elif oauth_enabled and not refresh_token_storage:
+                    logger.warning(
+                        "Vector sync enabled but refresh token storage not available"
+                    )
+                elif oauth_enabled and not encryption_key:
+                    logger.warning(
+                        "Vector sync enabled but TOKEN_ENCRYPTION_KEY not set"
+                    )
             async with AsyncExitStack() as stack:
                 await stack.enter_async_context(mcp.session_manager.run())
                 yield
@@ -1491,6 +1704,46 @@ def get_app(transport: str = "streamable-http", enabled_apps: list[str] | None =
     )
     logger.info("Test webhook endpoint enabled: /webhooks/nextcloud")
 
+    # Add management API endpoints for Nextcloud PHP app (OAuth mode only)
+    if oauth_enabled:
+        from nextcloud_mcp_server.api.management import (
+            get_server_status,
+            get_user_session,
+            get_vector_sync_status,
+            revoke_user_access,
+            vector_search,
+        )
+
+        routes.append(Route("/api/v1/status", get_server_status, methods=["GET"]))
+        routes.append(
+            Route(
+                "/api/v1/vector-sync/status",
+                get_vector_sync_status,
+                methods=["GET"],
+            )
+        )
+        routes.append(
+            Route(
+                "/api/v1/users/{user_id}/session",
+                get_user_session,
+                methods=["GET"],
+            )
+        )
+        routes.append(
+            Route(
+                "/api/v1/users/{user_id}/revoke",
+                revoke_user_access,
+                methods=["POST"],
+            )
+        )
+        routes.append(
+            Route("/api/v1/vector-viz/search", vector_search, methods=["POST"])
+        )
+        logger.info(
+            "Management API endpoints enabled: /api/v1/status, /api/v1/vector-sync/status, "
+            "/api/v1/users/{user_id}/session, /api/v1/users/{user_id}/revoke, /api/v1/vector-viz/search"
+        )
+
     # ADR-016: Add Smithery well-known config endpoint for container runtime discovery
     if deployment_mode == DeploymentMode.SMITHERY_STATELESS:
 

nextcloud_mcp_server/auth/browser_oauth_routes.py

@@ -50,6 +50,10 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
     logger.info(f"oauth_login called - client_id: {oauth_config.get('client_id')}")
     logger.info(f"oauth_login called - oauth_client: {oauth_client is not None}")
 
+    # Get redirect URL from query params (default to /app)
+    next_url = request.query_params.get("next", "/app")
+    logger.info(f"oauth_login - next_url: {next_url}")
+
     # Generate state for CSRF protection
     state = secrets.token_urlsafe(32)
 
@@ -71,7 +75,7 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
     await storage.store_oauth_session(
         session_id=state,  # Use state as session ID
         client_id="browser-ui",
-        client_redirect_uri="/app",
+        client_redirect_uri=next_url,  # Store the redirect URL for after auth
         state=state,
         code_challenge=code_challenge,
         code_challenge_method="S256",
@@ -85,6 +89,11 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
         if not oauth_client.authorization_endpoint:
             await oauth_client.discover()
 
+        # Get Nextcloud resource URI for audience (background sync needs Nextcloud-scoped tokens)
+        nextcloud_resource_uri = oauth_config.get(
+            "nextcloud_resource_uri", oauth_config.get("nextcloud_host")
+        )
+
         idp_params = {
             "client_id": oauth_client.client_id,
             "redirect_uri": callback_uri,
@@ -94,6 +103,7 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
             "code_challenge": code_challenge,
             "code_challenge_method": "S256",
             "prompt": "consent",  # Ensure refresh token
+            "resource": nextcloud_resource_uri,  # Request tokens for Nextcloud API access
         }
 
         auth_url = f"{oauth_client.authorization_endpoint}?{urlencode(idp_params)}"
@@ -131,6 +141,11 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
                     f"{public_parsed.scheme}://{public_parsed.netloc}{auth_parsed.path}"
                 )
 
+        # Get Nextcloud resource URI for audience (background sync needs Nextcloud-scoped tokens)
+        nextcloud_resource_uri = oauth_config.get(
+            "nextcloud_resource_uri", oauth_config.get("nextcloud_host")
+        )
+
         idp_params = {
             "client_id": oauth_config["client_id"],
             "redirect_uri": callback_uri,
@@ -140,6 +155,7 @@ async def oauth_login(request: Request) -> RedirectResponse | JSONResponse:
             "code_challenge": code_challenge,
             "code_challenge_method": "S256",
             "prompt": "consent",  # Ensure refresh token
+            "resource": nextcloud_resource_uri,  # Request tokens for Nextcloud API access
         }
 
         # Debug: Log full parameters
@@ -214,12 +230,15 @@ async def oauth_login_callback(request: Request) -> RedirectResponse | HTMLRespo
     oauth_client = oauth_ctx["oauth_client"]
     oauth_config = oauth_ctx["config"]
 
-    # Retrieve code_verifier from session storage (PKCE required for all modes)
+    # Retrieve code_verifier and redirect URL from session storage
     code_verifier = ""
+    next_url = "/app"  # Default redirect
     oauth_session = await storage.get_oauth_session(state)
     if oauth_session:
         # code_verifier was stored in mcp_authorization_code field
         code_verifier = oauth_session.get("mcp_authorization_code", "")
+        # next_url was stored in client_redirect_uri field
+        next_url = oauth_session.get("client_redirect_uri", "/app")
         # Clean up the temporary session
         # Note: We don't have delete_oauth_session method, but it will expire after TTL
 
@@ -262,6 +281,25 @@ async def oauth_login_callback(request: Request) -> RedirectResponse | HTMLRespo
                 discovery = response.json()
                 token_endpoint = discovery["token_endpoint"]
 
+            # Rewrite token_endpoint from public URL to internal Docker URL
+            # Discovery document returns public URLs (e.g., http://localhost:8080/...)
+            # but server-side requests must use internal Docker network (e.g., http://app:80/...)
+            public_issuer = os.getenv("NEXTCLOUD_PUBLIC_ISSUER_URL")
+            if public_issuer:
+                from urllib.parse import urlparse as parse_url
+
+                internal_host = oauth_config["nextcloud_host"]
+                internal_parsed = parse_url(internal_host)
+                token_parsed = parse_url(token_endpoint)
+                public_parsed = parse_url(public_issuer)
+
+                if token_parsed.hostname == public_parsed.hostname:
+                    # Replace public URL with internal Docker URL
+                    token_endpoint = f"{internal_parsed.scheme}://{internal_parsed.netloc}{token_parsed.path}"
+                    logger.info(
+                        f"Rewrote token endpoint to internal URL: {token_endpoint}"
+                    )
+
             token_params = {
                 "grant_type": "authorization_code",
                 "code": code,
@@ -383,7 +421,8 @@ async def oauth_login_callback(request: Request) -> RedirectResponse | HTMLRespo
             # Continue anyway - profile cache is optional for browser UI
 
     # Create response and set session cookie
-    response = RedirectResponse("/app", status_code=302)
+    # Redirect to stored next_url (from OAuth session) or /app as default
+    response = RedirectResponse(next_url, status_code=302)
     response.set_cookie(
         key="mcp_session",
         value=user_id,

nextcloud_mcp_server/auth/token_broker.py

@@ -21,7 +21,6 @@ from typing import Dict, Optional, Tuple
 import anyio
 import httpx
 import jwt
-from cryptography.fernet import Fernet
 
 from nextcloud_mcp_server.auth.storage import RefreshTokenStorage
 from nextcloud_mcp_server.auth.token_exchange import exchange_token_for_delegation
@@ -104,7 +103,8 @@ class TokenBrokerService:
         storage: RefreshTokenStorage,
         oidc_discovery_url: str,
         nextcloud_host: str,
-        encryption_key: str,
+        client_id: str,
+        client_secret: str,
         cache_ttl: int = 300,
         cache_early_refresh: int = 30,
     ):
@@ -112,21 +112,19 @@ class TokenBrokerService:
         Initialize the Token Broker Service.
 
         Args:
-            storage: Database storage for refresh tokens
+            storage: Database storage for refresh tokens (handles encryption internally)
             oidc_discovery_url: OIDC provider discovery URL
             nextcloud_host: Nextcloud server URL
-            encryption_key: Fernet key for token encryption
+            client_id: OAuth client ID for token operations
+            client_secret: OAuth client secret for token operations
             cache_ttl: Cache TTL in seconds (default: 5 minutes)
             cache_early_refresh: Early refresh threshold in seconds (default: 30 seconds)
         """
         self.storage = storage
         self.oidc_discovery_url = oidc_discovery_url
         self.nextcloud_host = nextcloud_host
-        self.fernet = Fernet(
-            encryption_key.encode()
-            if isinstance(encryption_key, str)
-            else encryption_key
-        )
+        self.client_id = client_id
+        self.client_secret = client_secret
         self.cache = TokenCache(cache_ttl, cache_early_refresh)
         self._oidc_config = None
         self._http_client = None
@@ -148,6 +146,37 @@ class TokenBrokerService:
             self._oidc_config = response.json()
         return self._oidc_config
 
+    def _rewrite_token_endpoint(self, token_endpoint: str) -> str:
+        """Rewrite token endpoint from public URL to internal Docker URL.
+
+        OIDC discovery documents return public URLs (e.g., http://localhost:8080/...)
+        but server-side requests must use internal Docker network (e.g., http://app:80/...).
+
+        Args:
+            token_endpoint: Token endpoint URL from discovery document
+
+        Returns:
+            Rewritten URL using internal Docker host
+        """
+        import os
+        from urllib.parse import urlparse
+
+        public_issuer = os.getenv("NEXTCLOUD_PUBLIC_ISSUER_URL")
+        if not public_issuer:
+            return token_endpoint
+
+        internal_parsed = urlparse(self.nextcloud_host)
+        token_parsed = urlparse(token_endpoint)
+        public_parsed = urlparse(public_issuer)
+
+        if token_parsed.hostname == public_parsed.hostname:
+            # Replace public URL with internal Docker URL
+            rewritten = f"{internal_parsed.scheme}://{internal_parsed.netloc}{token_parsed.path}"
+            logger.info(f"Rewrote token endpoint: {token_endpoint} -> {rewritten}")
+            return rewritten
+
+        return token_endpoint
+
     async def get_nextcloud_token(self, user_id: str) -> Optional[str]:
         """
         Get a valid Nextcloud access token for the user.
@@ -180,9 +209,8 @@ class TokenBrokerService:
             return None
 
         try:
-            # Decrypt refresh token
-            encrypted_token = refresh_data["refresh_token"]
-            refresh_token = self.fernet.decrypt(encrypted_token.encode()).decode()
+            # storage.get_refresh_token() returns already-decrypted token
+            refresh_token = refresh_data["refresh_token"]
 
             # Exchange refresh token for new access token
             access_token, expires_in = await self._refresh_access_token(refresh_token)
@@ -282,9 +310,8 @@ class TokenBrokerService:
             return None
 
         try:
-            # Decrypt refresh token
-            encrypted_token = refresh_data["refresh_token"]
-            refresh_token = self.fernet.decrypt(encrypted_token.encode()).decode()
+            # storage.get_refresh_token() returns already-decrypted token
+            refresh_token = refresh_data["refresh_token"]
 
             # Get token with specific scopes for background operation
             access_token, expires_in = await self._refresh_access_token_with_scopes(
@@ -301,7 +328,10 @@ class TokenBrokerService:
             return access_token
 
         except Exception as e:
-            logger.error(f"Failed to get background token for user {user_id}: {e}")
+            logger.error(
+                f"Failed to get background token for user {user_id}: {e}",
+                exc_info=True,
+            )
             await self.cache.invalidate(cache_key)
             return None
 
@@ -318,15 +348,18 @@ class TokenBrokerService:
             Tuple of (access_token, expires_in_seconds)
         """
         config = await self._get_oidc_config()
-        token_endpoint = config["token_endpoint"]
+        token_endpoint = self._rewrite_token_endpoint(config["token_endpoint"])
 
         client = await self._get_http_client()
 
         # Request new access token using refresh token
+        # Include client credentials as required by most OAuth servers
         data = {
             "grant_type": "refresh_token",
             "refresh_token": refresh_token,
             "scope": "openid profile email notes:read notes:write calendar:read calendar:write",
+            "client_id": self.client_id,
+            "client_secret": self.client_secret,
         }
 
         response = await client.post(
@@ -345,8 +378,7 @@ class TokenBrokerService:
         access_token = token_data["access_token"]
         expires_in = token_data.get("expires_in", 3600)  # Default 1 hour
 
-        # Validate audience
-        await self._validate_token_audience(access_token, "nextcloud")
+        # Note: Nextcloud validates token audience on API calls - no need to pre-validate here
 
         logger.info(f"Refreshed access token (expires in {expires_in}s)")
         return access_token, expires_in
@@ -367,7 +399,7 @@ class TokenBrokerService:
             Tuple of (access_token, expires_in_seconds)
         """
         config = await self._get_oidc_config()
-        token_endpoint = config["token_endpoint"]
+        token_endpoint = self._rewrite_token_endpoint(config["token_endpoint"])
 
         client = await self._get_http_client()
 
@@ -375,12 +407,19 @@ class TokenBrokerService:
         scopes = list(set(["openid", "profile", "email"] + required_scopes))
 
         # Request new access token with specific scopes
+        # Include client credentials as required by most OAuth servers
         data = {
             "grant_type": "refresh_token",
             "refresh_token": refresh_token,
             "scope": " ".join(scopes),
+            "client_id": self.client_id,
+            "client_secret": self.client_secret,
         }
 
+        logger.info(
+            f"Token refresh request to {token_endpoint} with client_id={self.client_id[:16]}..."
+        )
+
         response = await client.post(
             token_endpoint,
             data=data,
@@ -391,14 +430,14 @@ class TokenBrokerService:
             logger.error(
                 f"Token refresh with scopes failed: {response.status_code} - {response.text}"
             )
+            logger.error(f"  client_id used: {self.client_id[:16]}...")
             raise Exception(f"Token refresh failed: {response.status_code}")
 
         token_data = response.json()
         access_token = token_data["access_token"]
         expires_in = token_data.get("expires_in", 3600)  # Default 1 hour
 
-        # Validate audience
-        await self._validate_token_audience(access_token, "nextcloud")
+        # Note: Nextcloud validates token audience on API calls - no need to pre-validate here
 
         logger.info(
             f"Refreshed access token with scopes {scopes} (expires in {expires_in}s)"
@@ -453,11 +492,8 @@ class TokenBrokerService:
             return False
 
         try:
-            # Decrypt current refresh token
-            encrypted_token = refresh_data["refresh_token"]
-            current_refresh_token = self.fernet.decrypt(
-                encrypted_token.encode()
-            ).decode()
+            # storage.get_refresh_token() returns already-decrypted token
+            current_refresh_token = refresh_data["refresh_token"]
 
             # Get OIDC configuration
             config = await self._get_oidc_config()
@@ -486,11 +522,10 @@ class TokenBrokerService:
             new_refresh_token = token_data.get("refresh_token")
 
             if new_refresh_token and new_refresh_token != current_refresh_token:
-                # Encrypt and store new refresh token
-                encrypted_new = self.fernet.encrypt(new_refresh_token.encode()).decode()
+                # storage.store_refresh_token() handles encryption internally
                 await self.storage.store_refresh_token(
                     user_id=user_id,
-                    refresh_token=encrypted_new,
+                    refresh_token=new_refresh_token,
                     expires_at=datetime.now(timezone.utc)
                     + timedelta(days=90),  # 90-day expiry
                 )
@@ -536,11 +571,8 @@ class TokenBrokerService:
             refresh_data = await self.storage.get_refresh_token(user_id)
             if refresh_data:
                 try:
-                    # Attempt to revoke at IdP
-                    encrypted_token = refresh_data["refresh_token"]
-                    refresh_token = self.fernet.decrypt(
-                        encrypted_token.encode()
-                    ).decode()
+                    # storage.get_refresh_token() returns already-decrypted token
+                    refresh_token = refresh_data["refresh_token"]
                     await self._revoke_token_at_idp(refresh_token)
                 except Exception as e:
                     logger.warning(f"Failed to revoke at IdP: {e}")

nextcloud_mcp_server/config.py

@@ -205,6 +205,7 @@ class Settings:
     vector_sync_scan_interval: int = 300  # seconds (5 minutes)
     vector_sync_processor_workers: int = 3
     vector_sync_queue_max_size: int = 10000
+    vector_sync_user_poll_interval: int = 60  # seconds - OAuth mode user discovery
 
     # Qdrant settings (mutually exclusive modes)
     qdrant_url: Optional[str] = None  # Network mode: http://qdrant:6333
@@ -391,6 +392,9 @@ def get_settings() -> Settings:
         vector_sync_queue_max_size=int(
             os.getenv("VECTOR_SYNC_QUEUE_MAX_SIZE", "10000")
         ),
+        vector_sync_user_poll_interval=int(
+            os.getenv("VECTOR_SYNC_USER_POLL_INTERVAL", "60")
+        ),
         # Qdrant settings
         qdrant_url=os.getenv("QDRANT_URL"),
         qdrant_location=os.getenv("QDRANT_LOCATION"),

nextcloud_mcp_server/vector/oauth_sync.py

@@ -0,0 +1,352 @@
+"""OAuth mode vector sync orchestration.
+
+Manages multi-user background vector sync when running in OAuth mode
+with ENABLE_OFFLINE_ACCESS=true:
+- User Manager: Monitors RefreshTokenStorage for user changes
+- Per-User Scanners: One scanner task per provisioned user
+- Shared Processor Pool: Processes documents from all users
+"""
+
+import logging
+import time
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
+
+import anyio
+from anyio.abc import TaskGroup, TaskStatus
+from anyio.streams.memory import (
+    MemoryObjectReceiveStream,
+    MemoryObjectSendStream,
+)
+
+from nextcloud_mcp_server.client import NextcloudClient
+from nextcloud_mcp_server.config import get_settings
+from nextcloud_mcp_server.vector.scanner import DocumentTask, scan_user_documents
+
+if TYPE_CHECKING:
+    from nextcloud_mcp_server.auth.storage import RefreshTokenStorage
+    from nextcloud_mcp_server.auth.token_broker import TokenBrokerService
+
+logger = logging.getLogger(__name__)
+
+# Scopes required for vector sync operations
+VECTOR_SYNC_SCOPES = [
+    "notes:read",
+    "files:read",
+    "deck:read",
+    # "news:read",  # News app may not be installed
+]
+
+
+class NotProvisionedError(Exception):
+    """User has not provisioned offline access or has revoked it."""
+
+    pass
+
+
+@dataclass
+class UserSyncState:
+    """State for a single user's scanner task."""
+
+    user_id: str
+    cancel_scope: anyio.CancelScope
+    started_at: float = field(default_factory=time.time)
+
+
+async def get_user_client(
+    user_id: str,
+    token_broker: "TokenBrokerService",
+    nextcloud_host: str,
+) -> NextcloudClient:
+    """Get an authenticated NextcloudClient for a user.
+
+    Args:
+        user_id: User identifier
+        token_broker: Token broker for obtaining access tokens
+        nextcloud_host: Nextcloud base URL
+
+    Returns:
+        Authenticated NextcloudClient
+
+    Raises:
+        NotProvisionedError: If user has not provisioned offline access
+    """
+    token = await token_broker.get_background_token(user_id, VECTOR_SYNC_SCOPES)
+    if not token:
+        raise NotProvisionedError(f"User {user_id} has not provisioned offline access")
+
+    return NextcloudClient.from_token(
+        base_url=nextcloud_host,
+        token=token,
+        username=user_id,
+    )
+
+
+async def user_scanner_task(
+    user_id: str,
+    send_stream: MemoryObjectSendStream[DocumentTask],
+    shutdown_event: anyio.Event,
+    wake_event: anyio.Event,
+    token_broker: "TokenBrokerService",
+    nextcloud_host: str,
+    *,
+    task_status: TaskStatus = anyio.TASK_STATUS_IGNORED,
+) -> None:
+    """Scanner task for a single user in OAuth mode.
+
+    Gets a fresh token at the start of each scan cycle.
+
+    Args:
+        user_id: User to scan
+        send_stream: Stream to send changed documents to processors
+        shutdown_event: Event signaling shutdown
+        wake_event: Event to trigger immediate scan
+        token_broker: Token broker for obtaining access tokens
+        nextcloud_host: Nextcloud base URL
+        task_status: Status object for signaling task readiness
+    """
+    logger.info(f"[OAuth] Scanner started for user: {user_id}")
+    settings = get_settings()
+
+    task_status.started()
+
+    while not shutdown_event.is_set():
+        nc_client = None
+        try:
+            # Get fresh token for this scan cycle
+            nc_client = await get_user_client(user_id, token_broker, nextcloud_host)
+
+            # Scan user's documents
+            await scan_user_documents(
+                user_id=user_id,
+                send_stream=send_stream,
+                nc_client=nc_client,
+            )
+
+        except NotProvisionedError:
+            logger.warning(
+                f"[OAuth] User {user_id} no longer provisioned, stopping scanner"
+            )
+            break
+
+        except Exception as e:
+            logger.error(f"[OAuth] Scanner error for {user_id}: {e}", exc_info=True)
+
+        finally:
+            if nc_client:
+                await nc_client.close()
+
+        # Sleep until next interval or wake event
+        try:
+            with anyio.move_on_after(settings.vector_sync_scan_interval):
+                await wake_event.wait()
+        except anyio.get_cancelled_exc_class():
+            break
+
+    logger.info(f"[OAuth] Scanner stopped for user: {user_id}")
+
+
+async def oauth_processor_task(
+    worker_id: int,
+    receive_stream: MemoryObjectReceiveStream[DocumentTask],
+    shutdown_event: anyio.Event,
+    token_broker: "TokenBrokerService",
+    nextcloud_host: str,
+    *,
+    task_status: TaskStatus = anyio.TASK_STATUS_IGNORED,
+) -> None:
+    """Processor task for OAuth mode.
+
+    Handles documents from any user by fetching tokens on-demand.
+
+    Args:
+        worker_id: Worker identifier for logging
+        receive_stream: Stream to receive documents from
+        shutdown_event: Event signaling shutdown
+        token_broker: Token broker for obtaining access tokens
+        nextcloud_host: Nextcloud base URL
+        task_status: Status object for signaling task readiness
+    """
+    from nextcloud_mcp_server.vector.processor import process_document
+
+    logger.info(f"[OAuth] Processor {worker_id} started")
+    task_status.started()
+
+    while not shutdown_event.is_set():
+        doc_task = None
+        nc_client = None
+        try:
+            # Get document with timeout
+            with anyio.fail_after(1.0):
+                doc_task = await receive_stream.receive()
+
+            # Get token for THIS document's user
+            nc_client = await get_user_client(
+                doc_task.user_id, token_broker, nextcloud_host
+            )
+
+            # Process the document
+            await process_document(doc_task, nc_client)
+
+        except TimeoutError:
+            continue
+
+        except anyio.EndOfStream:
+            logger.info(f"[OAuth] Processor {worker_id}: Stream closed, exiting")
+            break
+
+        except NotProvisionedError:
+            if doc_task:
+                logger.warning(
+                    f"[OAuth] User {doc_task.user_id} not provisioned, "
+                    f"skipping {doc_task.doc_type}_{doc_task.doc_id}"
+                )
+            continue
+
+        except Exception as e:
+            if doc_task:
+                logger.error(
+                    f"[OAuth] Processor {worker_id} error processing "
+                    f"{doc_task.doc_type}_{doc_task.doc_id}: {e}",
+                    exc_info=True,
+                )
+            else:
+                logger.error(f"[OAuth] Processor {worker_id} error: {e}", exc_info=True)
+
+        finally:
+            if nc_client:
+                await nc_client.close()
+
+    logger.info(f"[OAuth] Processor {worker_id} stopped")
+
+
+async def _run_user_scanner_with_scope(
+    user_id: str,
+    cancel_scope: anyio.CancelScope,
+    send_stream: MemoryObjectSendStream[DocumentTask],
+    shutdown_event: anyio.Event,
+    wake_event: anyio.Event,
+    token_broker: "TokenBrokerService",
+    nextcloud_host: str,
+    user_states: dict[str, UserSyncState],
+) -> None:
+    """Wrapper to run scanner with cancellation scope.
+
+    Cleans up user state on exit.
+    """
+    cloned_stream = send_stream.clone()
+    try:
+        with cancel_scope:
+            await user_scanner_task(
+                user_id=user_id,
+                send_stream=cloned_stream,
+                shutdown_event=shutdown_event,
+                wake_event=wake_event,
+                token_broker=token_broker,
+                nextcloud_host=nextcloud_host,
+            )
+    finally:
+        # Clean up on exit
+        if user_id in user_states:
+            del user_states[user_id]
+        await cloned_stream.aclose()
+
+
+async def user_manager_task(
+    send_stream: MemoryObjectSendStream[DocumentTask],
+    shutdown_event: anyio.Event,
+    wake_event: anyio.Event,
+    token_broker: "TokenBrokerService",
+    refresh_token_storage: "RefreshTokenStorage",
+    nextcloud_host: str,
+    user_states: dict[str, UserSyncState],
+    tg: TaskGroup,
+    *,
+    task_status: TaskStatus = anyio.TASK_STATUS_IGNORED,
+) -> None:
+    """Supervisor task that manages per-user scanners.
+
+    Periodically polls RefreshTokenStorage to detect:
+    - New users who have provisioned offline access -> start scanner
+    - Users who have revoked access -> cancel their scanner
+
+    Args:
+        send_stream: Stream to send documents to processors
+        shutdown_event: Event signaling shutdown
+        wake_event: Event to wake scanners for immediate scan
+        token_broker: Token broker for obtaining access tokens
+        refresh_token_storage: Storage for refresh tokens
+        nextcloud_host: Nextcloud base URL
+        user_states: Shared dict tracking active user scanners
+        tg: Task group for spawning scanner tasks
+        task_status: Status object for signaling task readiness
+    """
+    settings = get_settings()
+    poll_interval = settings.vector_sync_user_poll_interval
+
+    logger.info(f"[OAuth] User manager started (poll interval: {poll_interval}s)")
+    task_status.started()
+
+    while not shutdown_event.is_set():
+        try:
+            # Get current provisioned users
+            provisioned_users = set(await refresh_token_storage.get_all_user_ids())
+            active_users = set(user_states.keys())
+
+            # Start scanners for new users
+            new_users = provisioned_users - active_users
+            for user_id in new_users:
+                logger.info(
+                    f"[OAuth] Starting scanner for newly provisioned user: {user_id}"
+                )
+                cancel_scope = anyio.CancelScope()
+                user_states[user_id] = UserSyncState(
+                    user_id=user_id,
+                    cancel_scope=cancel_scope,
+                )
+
+                # Start scanner in task group
+                tg.start_soon(
+                    _run_user_scanner_with_scope,
+                    user_id,
+                    cancel_scope,
+                    send_stream,
+                    shutdown_event,
+                    wake_event,
+                    token_broker,
+                    nextcloud_host,
+                    user_states,
+                )
+
+            # Cancel scanners for revoked users
+            revoked_users = active_users - provisioned_users
+            for user_id in revoked_users:
+                logger.info(f"[OAuth] Stopping scanner for revoked user: {user_id}")
+                state = user_states.get(user_id)
+                if state:
+                    state.cancel_scope.cancel()
+                    # Note: state will be removed by _run_user_scanner_with_scope on exit
+
+            if new_users:
+                logger.info(f"[OAuth] Started {len(new_users)} new scanner(s)")
+            if revoked_users:
+                logger.info(f"[OAuth] Stopped {len(revoked_users)} scanner(s)")
+
+        except Exception as e:
+            logger.error(f"[OAuth] User manager error: {e}", exc_info=True)
+
+        # Sleep until next poll
+        try:
+            with anyio.move_on_after(poll_interval):
+                await shutdown_event.wait()
+        except anyio.get_cancelled_exc_class():
+            break
+
+    # Cancel all remaining scanners on shutdown
+    logger.info(
+        f"[OAuth] User manager shutting down, cancelling {len(user_states)} scanner(s)"
+    )
+    for state in list(user_states.values()):
+        state.cancel_scope.cancel()
+
+    logger.info("[OAuth] User manager stopped")