diff --git a/src/langbot/pkg/api/http/controller/groups/user.py b/src/langbot/pkg/api/http/controller/groups/user.py
index 5b579cd7a..8fa38bf73 100644
--- a/src/langbot/pkg/api/http/controller/groups/user.py
+++ b/src/langbot/pkg/api/http/controller/groups/user.py
@@ -258,7 +258,7 @@ class UserRouterGroup(group.RouterGroup):
             except ControlPlaneDirectoryRequiredError as e:
                 return self.http_status(409, e.code, str(e))
             except account_errors.AccountEmailMismatchError as e:
-                return self.fail(3, str(e))
+                return self.fail(getattr(e, 'code', 3), str(e))
             except ValueError:
                 self.ap.logger.exception('Space OAuth callback failed')
                 return self.fail(1, 'Space OAuth failed')
@@ -278,10 +278,22 @@ class UserRouterGroup(group.RouterGroup):
             )
 
         @self.route('/space-credits', methods=['GET'], auth_type=group.AuthType.USER_TOKEN)
-        async def _(user_email: str) -> str:
-            """Get Space credits balance for current user"""
-            credits = await self.ap.space_service.get_credits(user_email)
-            return self.success(data={'credits': credits})
+        async def _(request_context: RequestContext) -> str:
+            """Get Space credits using only the selected Workspace owner's credentials."""
+            access = await self.ap.workspace_collaboration_service.resolve_account_workspace(
+                request_context.account_uuid,
+                request_context.workspace_uuid,
+            )
+            owner = await self.ap.user_service.get_workspace_owner(access.workspace.uuid)
+            owner_space_bound = bool(owner and owner.space_account_uuid)
+            credits = await self.ap.space_service.get_credits(owner.user) if owner_space_bound else None
+            return self.success(
+                data={
+                    'credits': credits,
+                    'owner_space_bound': owner_space_bound,
+                    'is_workspace_owner': access.membership.role == 'owner',
+                }
+            )
 
         @self.route('/account-info', methods=['GET'], auth_type=group.AuthType.NONE)
         async def _() -> str:
@@ -289,16 +301,10 @@ class UserRouterGroup(group.RouterGroup):
             if not await self.ap.user_service.is_initialized():
                 return self.success(data={'initialized': False})
 
-            return self.success(
-                data={
-                    'initialized': True,
-                    # Login is selected per account in a multi-user instance. A public
-                    # bootstrap endpoint must never project one user's authentication
-                    # methods onto every other user or disclose that user's state.
-                    'password_login_enabled': getattr(getattr(self.ap, 'deployment', None), 'mode', 'oss') != 'cloud',
-                    'space_login_enabled': True,
-                }
-            )
+            capabilities = await self.ap.user_service.get_login_capabilities()
+            if getattr(getattr(self.ap, 'deployment', None), 'mode', 'oss') == 'cloud':
+                capabilities['password_login_enabled'] = False
+            return self.success(data={'initialized': True, **capabilities})
 
         @self.route('/set-password', methods=['POST'], auth_type=group.AuthType.USER_TOKEN)
         async def _(user_email: str) -> str:
@@ -369,8 +375,13 @@ class UserRouterGroup(group.RouterGroup):
                         'account_type': updated_user.account_type,
                     }
                 )
+            except account_errors.AccountEmailMismatchError:
+                return self.http_status(
+                    409,
+                    'space_account_email_mismatch',
+                    'Bind the LangBot Account with the same email as this local Account',
+                )
             except ValueError:
-                self.ap.logger.exception('Space account binding failed')
                 return self.http_status(400, -1, 'Space account binding failed')
             except Exception:
                 raise
diff --git a/src/langbot/pkg/api/http/controller/groups/workspaces.py b/src/langbot/pkg/api/http/controller/groups/workspaces.py
index 6390777c6..5c43cf64b 100644
--- a/src/langbot/pkg/api/http/controller/groups/workspaces.py
+++ b/src/langbot/pkg/api/http/controller/groups/workspaces.py
@@ -311,6 +311,12 @@ class InvitationsRouterGroup(group.RouterGroup):
 
             authorization = quart.request.headers.get('Authorization', '')
             if authorization.startswith('Bearer '):
+                if getattr(getattr(self.ap, 'deployment', None), 'mode', 'oss') != 'cloud':
+                    return self.http_status(
+                        409,
+                        'invitation_logout_required',
+                        'Sign out before creating the invited local Account',
+                    )
                 try:
                     account = await self.ap.user_service.get_authenticated_account(
                         authorization.removeprefix('Bearer ')
@@ -345,7 +351,7 @@ class InvitationsRouterGroup(group.RouterGroup):
             if not isinstance(password, str) or len(password) < 8:
                 return self.http_status(400, 'invalid_password', 'Password must contain at least 8 characters')
             try:
-                _, membership, token = await self.ap.user_service.register_invited_account(
+                _, membership = await self.ap.user_service.register_invited_account(
                     invitation_token,
                     str(registration.get('email', '')),
                     password,
@@ -354,4 +360,4 @@ class InvitationsRouterGroup(group.RouterGroup):
                 return self.http_status(409, exc.code, str(exc))
             except AccountExistsLoginRequiredError as exc:
                 return self.http_status(409, exc.code, str(exc))
-            return self.success(data={'token': token, 'workspace_uuid': membership.workspace_uuid})
+            return self.success(data={'workspace_uuid': membership.workspace_uuid, 'login_required': True})
diff --git a/src/langbot/pkg/api/http/service/user.py b/src/langbot/pkg/api/http/service/user.py
index f665ff8ac..001ac4309 100644
--- a/src/langbot/pkg/api/http/service/user.py
+++ b/src/langbot/pkg/api/http/service/user.py
@@ -15,10 +15,10 @@ import uuid
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 
 from ....entity.persistence import user
+from ....entity.persistence.workspace import MembershipRole, MembershipStatus, WorkspaceMembership
 from ....utils import constants
 from ....entity.errors import account as account_errors
 from ....workspace.collaboration import normalize_email
-from ..authz import Permission, permissions_for_role
 
 if typing.TYPE_CHECKING:
     from ....core.app import Application
@@ -151,8 +151,8 @@ class UserService:
 
         Space OAuth credentials belong to an Account, while model-provider secrets
         belong to a Workspace. Community edition has one unambiguous Workspace, so
-        the historical automatic refresh remains available to members allowed to
-        manage provider secrets. In multi-Workspace SaaS mode the OAuth callback has
+        the historical automatic refresh remains available only to the Workspace owner.
+        In multi-Workspace SaaS mode the OAuth callback has
         no trusted Workspace selector; the closed control plane or an explicit
         Workspace settings action must perform that linkage instead.
         """
@@ -170,7 +170,7 @@ class UserService:
         if len(accesses) != 1:
             return
         access = accesses[0]
-        if Permission.PROVIDER_SECRET_MANAGE.value not in permissions_for_role(access.membership.role):
+        if access.membership.role != MembershipRole.OWNER.value:
             return
         await self.ap.provider_service.update_space_model_provider_api_keys(
             access.workspace.uuid,
@@ -184,6 +184,37 @@ class UserService:
         )
         return account is not None
 
+    async def get_login_capabilities(self) -> dict[str, bool]:
+        """Derive enabled public login methods from all active Accounts."""
+        password_count = sqlalchemy.func.count().filter(
+            user.User.password.is_not(None), user.User.password != ''
+        )
+        space_count = sqlalchemy.func.count().filter(user.User.space_account_uuid.is_not(None))
+        result = await self.ap.persistence_mgr.execute_async(
+            sqlalchemy.select(password_count, space_count).where(
+                user.User.status == user.AccountStatus.ACTIVE.value
+            )
+        )
+        password_accounts, space_accounts = result.one()
+        return {
+            'password_login_enabled': bool(password_accounts),
+            'space_login_enabled': bool(space_accounts),
+        }
+
+    async def get_workspace_owner(self, workspace_uuid: str) -> user.User | None:
+        """Resolve the active owner Account for a Workspace."""
+        result = await self.ap.persistence_mgr.execute_async(
+            sqlalchemy.select(user.User)
+            .join(WorkspaceMembership, WorkspaceMembership.account_uuid == user.User.uuid)
+            .where(
+                WorkspaceMembership.workspace_uuid == workspace_uuid,
+                WorkspaceMembership.role == MembershipRole.OWNER.value,
+                WorkspaceMembership.status == MembershipStatus.ACTIVE.value,
+                user.User.status == user.AccountStatus.ACTIVE.value,
+            )
+        )
+        return result.scalar_one_or_none()
+
     def _session_factory(self) -> async_sessionmaker[AsyncSession]:
         return async_sessionmaker(self.ap.persistence_mgr.get_db_engine(), expire_on_commit=False)
 
@@ -230,7 +261,7 @@ class UserService:
         invitation_token: str,
         user_email: str,
         password: str,
-    ) -> tuple[user.User, typing.Any, str]:
+    ) -> tuple[user.User, typing.Any]:
         """Create an invited Account and accept its Membership in one transaction."""
 
         normalized_email = normalize_email(user_email)
@@ -261,8 +292,7 @@ class UserService:
                         account.uuid,
                         session=session,
                     )
-                token = await self.generate_jwt_token(account)
-                return account, membership, token
+                return account, membership
 
     def _new_account(self, normalized_email: str, hashed_password: str) -> user.User:
         return user.User(
@@ -497,12 +527,12 @@ class UserService:
                 # Account merely by presenting the same email. The Account
                 # owner must first authenticate locally and use the explicit,
                 # account-bound bind flow.
-                raise account_errors.AccountEmailMismatchError()
+                raise account_errors.SpaceAccountBindingRequiredError()
 
             # Check if system is already initialized
             is_initialized = await self.is_initialized()
             if is_initialized:
-                raise account_errors.AccountEmailMismatchError()
+                raise account_errors.SpaceAccountNotRegisteredError()
 
             # Create new Space user (first time initialization)
             if hasattr(self.ap.persistence_mgr, 'get_db_engine') and hasattr(self.ap, 'workspace_service'):
@@ -707,6 +737,8 @@ class UserService:
 
         if not space_account_uuid or not space_email:
             raise ValueError('Invalid Space user info')
+        if normalize_email(space_email) != normalize_email(user_email):
+            raise account_errors.AccountEmailMismatchError()
 
         # Check if this Space account is already bound to another user
         existing_space_user = await self.get_user_by_space_account_uuid(space_account_uuid)
diff --git a/src/langbot/pkg/entity/errors/account.py b/src/langbot/pkg/entity/errors/account.py
index edd5b41fa..a2d0f1e85 100644
--- a/src/langbot/pkg/entity/errors/account.py
+++ b/src/langbot/pkg/entity/errors/account.py
@@ -2,5 +2,19 @@ from __future__ import annotations
 
 
 class AccountEmailMismatchError(Exception):
-    def __str__(self):
+    def __str__(self) -> str:
         return 'Account email mismatch'
+
+
+class SpaceAccountNotRegisteredError(AccountEmailMismatchError):
+    code = 'space_account_not_registered'
+
+    def __str__(self) -> str:
+        return 'No Account is registered for this Space email'
+
+
+class SpaceAccountBindingRequiredError(AccountEmailMismatchError):
+    code = 'space_account_binding_required'
+
+    def __str__(self) -> str:
+        return 'This local Account must bind Space from Account settings before Space login'
diff --git a/tests/integration/api/test_smoke.py b/tests/integration/api/test_smoke.py
index 58a7c2a01..92087fca4 100644
--- a/tests/integration/api/test_smoke.py
+++ b/tests/integration/api/test_smoke.py
@@ -86,7 +86,7 @@ def fake_api_app():
             'api': {'port': 5300},
             'plugin': {'enable_marketplace': True},
             'space': {'url': 'https://space.langbot.app'},
-            'system': {'allow_modify_login_info': True, 'limitation': {}},
+            'system': {'allow_modify_login_info': True, 'recovery_key': 'recovery-secret', 'limitation': {}},
         }
     )
 
@@ -291,6 +291,9 @@ class TestUserInitEndpoint:
     @pytest.mark.asyncio
     async def test_account_info_exposes_instance_capabilities_not_first_account(self, quart_test_client, fake_api_app):
         fake_api_app.user_service.is_initialized.return_value = True
+        fake_api_app.user_service.get_login_capabilities = AsyncMock(
+            return_value={'password_login_enabled': True, 'space_login_enabled': False}
+        )
         fake_api_app.user_service.get_first_user = AsyncMock(
             side_effect=AssertionError('public login bootstrap must not inspect an account')
         )
@@ -302,10 +305,32 @@ class TestUserInitEndpoint:
         assert data['data'] == {
             'initialized': True,
             'password_login_enabled': True,
-            'space_login_enabled': True,
+            'space_login_enabled': False,
         }
+        fake_api_app.user_service.get_login_capabilities.assert_awaited_once_with()
         fake_api_app.user_service.get_first_user.assert_not_awaited()
 
+    @pytest.mark.asyncio
+    async def test_recovery_key_resets_any_existing_account(self, quart_test_client, fake_api_app, monkeypatch):
+        fake_api_app.user_service.is_initialized.return_value = True
+        fake_api_app.user_service.get_user_by_email.return_value = Mock(user='member@example.com')
+        fake_api_app.user_service.reset_password = AsyncMock()
+        monkeypatch.setattr('langbot.pkg.api.http.controller.groups.user.asyncio.sleep', AsyncMock())
+
+        response = await quart_test_client.post(
+            '/api/v1/user/reset-password',
+            json={
+                'user': 'member@example.com',
+                'recovery_key': 'recovery-secret',
+                'new_password': 'new-member-password',
+            },
+        )
+
+        assert response.status_code == 200
+        fake_api_app.user_service.reset_password.assert_awaited_once_with(
+            'member@example.com', 'new-member-password'
+        )
+
 
 @pytest.mark.usefixtures('mock_circular_import_chain')
 class TestRealImports:
diff --git a/tests/integration/api/test_user_space_oauth.py b/tests/integration/api/test_user_space_oauth.py
index a662a715e..17569707c 100644
--- a/tests/integration/api/test_user_space_oauth.py
+++ b/tests/integration/api/test_user_space_oauth.py
@@ -260,6 +260,28 @@ async def test_login_callback_launch_state_selects_asserted_workspace(space_oaut
     )
 
 
+@pytest.mark.asyncio
+async def test_space_credits_are_resolved_from_workspace_owner(space_oauth_api):
+    application, client = space_oauth_api
+    application.user_service.get_workspace_owner = AsyncMock(
+        return_value=SimpleNamespace(user='owner@example.com', space_account_uuid='space-owner')
+    )
+    application.space_service.get_credits = AsyncMock(return_value=25000)
+
+    response = await client.get(
+        '/api/v1/user/space-credits',
+        headers={'Authorization': 'Bearer account-token', 'X-Workspace-UUID': WORKSPACE_UUID},
+    )
+
+    assert response.status_code == 200
+    assert (await response.get_json())['data'] == {
+        'credits': 25000,
+        'owner_space_bound': True,
+        'is_workspace_owner': True,
+    }
+    application.space_service.get_credits.assert_awaited_once_with('owner@example.com')
+
+
 @pytest.mark.asyncio
 async def test_bind_callback_uses_opaque_state_and_never_treats_it_as_jwt(space_oauth_api):
     application, client = space_oauth_api
diff --git a/tests/integration/api/test_workspaces.py b/tests/integration/api/test_workspaces.py
index 3414f5561..7547f4800 100644
--- a/tests/integration/api/test_workspaces.py
+++ b/tests/integration/api/test_workspaces.py
@@ -231,8 +231,15 @@ async def test_owner_invites_second_account_and_secret_is_not_persisted(workspac
         },
     )
     assert accept_response.status_code == 200
-    member_auth = (await accept_response.get_json())['data']
-    assert member_auth['workspace_uuid'] == workspace_uuid
+    member_registration = (await accept_response.get_json())['data']
+    assert member_registration == {'workspace_uuid': workspace_uuid, 'login_required': True}
+
+    member_login_response = await client.post(
+        '/api/v1/user/auth',
+        json={'user': 'member@example.com', 'password': 'member-password'},
+    )
+    assert member_login_response.status_code == 200
+    member_token = (await member_login_response.get_json())['data']['token']
 
     reused_response = await client.post(
         '/api/v1/invitations/accept',
@@ -249,7 +256,7 @@ async def test_owner_invites_second_account_and_secret_is_not_persisted(workspac
 
     member_current_response = await client.get(
         '/api/v1/workspaces/current',
-        headers=_auth(member_auth['token'], workspace_uuid),
+        headers=_auth(member_token, workspace_uuid),
     )
     assert member_current_response.status_code == 200
     member_current = (await member_current_response.get_json())['data']
@@ -258,15 +265,29 @@ async def test_owner_invites_second_account_and_secret_is_not_persisted(workspac
 
     forbidden_invite = await client.post(
         f'/api/v1/workspaces/{workspace_uuid}/invitations',
-        headers=_auth(member_auth['token'], workspace_uuid),
+        headers=_auth(member_token, workspace_uuid),
         json={'email': 'third@example.com', 'role': 'viewer'},
     )
     assert forbidden_invite.status_code == 403
     assert (await forbidden_invite.get_json())['code'] == 'permission_denied'
 
 
-async def test_invitation_accept_rejects_invalid_bearer_as_authentication_failure(workspace_api):
-    _, client, _, _ = workspace_api
+async def test_oss_invitation_accept_requires_logout_before_registration(workspace_api):
+    _, client, _, owner_token = workspace_api
+
+    response = await client.post(
+        '/api/v1/invitations/accept',
+        headers={'Authorization': f'Bearer {owner_token}'},
+        json={'token': 'lbi_pending-invitation'},
+    )
+
+    assert response.status_code == 409
+    assert (await response.get_json())['code'] == 'invitation_logout_required'
+
+
+async def test_invalid_bearer_on_cloud_invitation_is_authentication_failure(workspace_api):
+    application, client, _, _ = workspace_api
+    application.deployment = SimpleNamespace(mode='cloud')
 
     response = await client.post(
         '/api/v1/invitations/accept',
@@ -368,7 +389,14 @@ async def test_api_key_secret_is_one_time_and_viewer_cannot_manage_keys(workspac
             'registration': {'email': 'viewer@example.com', 'password': 'viewer-password'},
         },
     )
-    viewer_token = (await accept_response.get_json())['data']['token']
+    assert accept_response.status_code == 200
+    assert (await accept_response.get_json())['data']['login_required'] is True
+    login_response = await client.post(
+        '/api/v1/user/auth',
+        json={'user': 'viewer@example.com', 'password': 'viewer-password'},
+    )
+    assert login_response.status_code == 200
+    viewer_token = (await login_response.get_json())['data']['token']
     forbidden = await client.post(
         '/api/v1/apikeys',
         headers=_auth(viewer_token, workspace_uuid),
@@ -382,6 +410,7 @@ async def test_cloud_projection_is_selected_explicitly_and_collaboration_runs_in
     workspace_api,
 ):
     application, client, engine, owner_token = workspace_api
+    application.deployment = SimpleNamespace(mode='cloud')
     owner_uuid = jwt.decode(
         owner_token,
         'workspace-api-secret',
@@ -537,8 +566,8 @@ async def test_cloud_projection_is_selected_explicitly_and_collaboration_runs_in
             'registration': {'email': 'member@example.com', 'password': 'member-password'},
         },
     )
-    assert registration_response.status_code == 409
-    assert (await registration_response.get_json())['code'] == 'control_plane_required'
+    assert registration_response.status_code == 401
+    assert (await registration_response.get_json())['code'] == 'account_exists_login_required'
 
 
 async def test_account_bootstrap_does_not_disclose_non_member_workspaces(workspace_api):
diff --git a/tests/unit_tests/api/service/test_user_service.py b/tests/unit_tests/api/service/test_user_service.py
index ab22712c1..84f936a6b 100644
--- a/tests/unit_tests/api/service/test_user_service.py
+++ b/tests/unit_tests/api/service/test_user_service.py
@@ -24,7 +24,11 @@ from langbot.pkg.api.http.service.user import (
     UserService,
 )
 from langbot.pkg.entity.persistence.user import AccountSource, AccountStatus, User
-from langbot.pkg.entity.errors.account import AccountEmailMismatchError
+from langbot.pkg.entity.errors.account import (
+    AccountEmailMismatchError,
+    SpaceAccountBindingRequiredError,
+    SpaceAccountNotRegisteredError,
+)
 
 
 pytestmark = pytest.mark.asyncio
@@ -97,6 +101,7 @@ def _create_mock_user(
     """Helper to create mock User entity."""
     user = Mock(spec=User)
     user.user = email
+    user.uuid = f'account-{email}'
     user.password = password
     user.account_type = account_type
     user.space_account_uuid = space_account_uuid
@@ -694,8 +699,8 @@ class TestUserServiceCreateOrUpdateSpaceUser:
         # Verify
         assert result.space_account_uuid == 'new-space-uuid'
 
-    async def test_create_or_update_space_user_already_initialized_raises_error(self):
-        """Raises AccountEmailMismatchError when system already initialized and user not found."""
+    async def test_create_or_update_space_user_already_initialized_reports_unknown_space_email(self):
+        """Unknown Space email is distinct from an existing local Account collision."""
         # Setup
         ap = SimpleNamespace()
         ap.persistence_mgr = SimpleNamespace()
@@ -710,7 +715,7 @@ class TestUserServiceCreateOrUpdateSpaceUser:
         service.is_initialized = AsyncMock(return_value=True)  # Already initialized
 
         # Execute & Verify
-        with pytest.raises(AccountEmailMismatchError):
+        with pytest.raises(SpaceAccountNotRegisteredError):
             await service.create_or_update_space_user(
                 space_account_uuid='unknown-space-uuid',
                 email='unknown@example.com',
@@ -747,7 +752,7 @@ class TestUserServiceCreateOrUpdateSpaceUser:
         service.get_user_by_email = AsyncMock(return_value=existing_user)
         service.generate_jwt_token = AsyncMock(return_value='must-not-be-issued')
 
-        with pytest.raises(AccountEmailMismatchError):
+        with pytest.raises(SpaceAccountBindingRequiredError):
             await service.authenticate_space_user(
                 'attacker-access-token',
                 'attacker-refresh-token',
@@ -758,6 +763,46 @@ class TestUserServiceCreateOrUpdateSpaceUser:
         ap.provider_service.update_space_model_provider_api_keys.assert_not_awaited()
         service.generate_jwt_token.assert_not_awaited()
 
+    async def test_oss_space_provider_refresh_requires_workspace_owner(self):
+        member_account = _create_mock_user(email='member@example.com', space_account_uuid='space-member')
+        access = SimpleNamespace(
+            workspace=SimpleNamespace(uuid='workspace-a'),
+            membership=SimpleNamespace(role='admin'),
+        )
+        provider_service = SimpleNamespace(update_space_model_provider_api_keys=AsyncMock())
+        ap = SimpleNamespace(
+            workspace_service=SimpleNamespace(policy=SimpleNamespace(multi_workspace_enabled=False)),
+            workspace_collaboration_service=SimpleNamespace(
+                list_account_workspaces=AsyncMock(return_value=[access])
+            ),
+            provider_service=provider_service,
+        )
+
+        await UserService(ap)._update_space_provider_for_account(member_account, 'member-api-key')
+
+        provider_service.update_space_model_provider_api_keys.assert_not_awaited()
+
+    async def test_oss_space_provider_refresh_uses_workspace_owner_credentials(self):
+        owner_account = _create_mock_user(email='owner@example.com', space_account_uuid='space-owner')
+        access = SimpleNamespace(
+            workspace=SimpleNamespace(uuid='workspace-a'),
+            membership=SimpleNamespace(role='owner'),
+        )
+        provider_service = SimpleNamespace(update_space_model_provider_api_keys=AsyncMock())
+        ap = SimpleNamespace(
+            workspace_service=SimpleNamespace(policy=SimpleNamespace(multi_workspace_enabled=False)),
+            workspace_collaboration_service=SimpleNamespace(
+                list_account_workspaces=AsyncMock(return_value=[access])
+            ),
+            provider_service=provider_service,
+        )
+
+        await UserService(ap)._update_space_provider_for_account(owner_account, 'owner-api-key')
+
+        provider_service.update_space_model_provider_api_keys.assert_awaited_once_with(
+            'workspace-a', 'owner-api-key'
+        )
+
     async def test_create_or_update_space_user_no_expiry(self):
         """Creates Space user without token expiry."""
         # Setup
@@ -805,6 +850,49 @@ class TestUserServiceCreateOrUpdateSpaceUser:
         assert result.space_account_uuid == 'noexpiry-uuid'
 
 
+    async def test_bind_space_account_rejects_different_email(self):
+        service = UserService(SimpleNamespace())
+        service.get_user_by_email = AsyncMock(
+            return_value=_create_mock_user(email='invited@example.com')
+        )
+        service.ap.space_service = SimpleNamespace(
+            exchange_oauth_code=AsyncMock(
+                return_value={'access_token': 'access', 'refresh_token': 'refresh', 'expires_in': 3600}
+            ),
+            get_user_info_raw=AsyncMock(
+                return_value={
+                    'account': {'uuid': 'space-other', 'email': 'other@example.com'},
+                    'api_key': 'key',
+                }
+            ),
+        )
+        service.get_user_by_space_account_uuid = AsyncMock(return_value=None)
+        service._identity_execute = AsyncMock()
+
+        with pytest.raises(AccountEmailMismatchError):
+            await service.bind_space_account('invited@example.com', 'code')
+
+        service._identity_execute.assert_not_awaited()
+
+
+class TestUserServiceLoginCapabilities:
+    async def test_capabilities_are_derived_from_all_accounts(self):
+        result = SimpleNamespace(one=lambda: (2, 1))
+        ap = SimpleNamespace(persistence_mgr=SimpleNamespace(execute_async=AsyncMock(return_value=result)))
+
+        capabilities = await UserService(ap).get_login_capabilities()
+
+        assert capabilities == {'password_login_enabled': True, 'space_login_enabled': True}
+
+    async def test_capabilities_disable_absent_login_methods(self):
+        result = SimpleNamespace(one=lambda: (0, 0))
+        ap = SimpleNamespace(persistence_mgr=SimpleNamespace(execute_async=AsyncMock(return_value=result)))
+
+        capabilities = await UserService(ap).get_login_capabilities()
+
+        assert capabilities == {'password_login_enabled': False, 'space_login_enabled': False}
+
+
 class TestUserServiceCreateUserLock:
     """Tests for create_user_lock attribute."""
 
diff --git a/web/src/app/auth/space/callback/page.tsx b/web/src/app/auth/space/callback/page.tsx
index 2884fd951..33f3a4846 100644
--- a/web/src/app/auth/space/callback/page.tsx
+++ b/web/src/app/auth/space/callback/page.tsx
@@ -68,6 +68,9 @@ function SpaceOAuthCallbackContent() {
     'loading' | 'confirm' | 'success' | 'error'
   >('loading');
   const [errorMessage, setErrorMessage] = useState<string>('');
+  const [terminalErrorCode, setTerminalErrorCode] = useState<
+    'space_account_not_registered' | 'space_account_binding_required' | null
+  >(null);
   const [isBindMode, setIsBindMode] = useState(false);
   const [code, setCode] = useState<string | null>(null);
   const [isProcessing, setIsProcessing] = useState(false);
@@ -125,7 +128,15 @@ function SpaceOAuthCallbackContent() {
         }
 
         setStatus('error');
-        const errorObj = err as { msg?: string };
+        const errorObj = err as { code?: string; msg?: string };
+        if (
+          errorObj.code === 'space_account_not_registered' ||
+          errorObj.code === 'space_account_binding_required'
+        ) {
+          setTerminalErrorCode(errorObj.code);
+          setErrorMessage(t(`account.${errorObj.code}`));
+          return;
+        }
         const errMsg = (errorObj?.msg || '').toLowerCase();
         if (errMsg.includes('account email mismatch')) {
           setErrorMessage(t('account.spaceEmailMismatch'));
@@ -168,7 +179,11 @@ function SpaceOAuthCallbackContent() {
         }
 
         setStatus('error');
-        const errorObj = err as { msg?: string };
+        const errorObj = err as { code?: string; msg?: string };
+        if (errorObj.code === 'space_account_email_mismatch') {
+          setErrorMessage(t('account.spaceEmailMismatch'));
+          return;
+        }
         const errMsg = (errorObj?.msg || '').toLowerCase();
         if (errMsg.includes('account email mismatch')) {
           setErrorMessage(t('account.spaceEmailMismatch'));
@@ -278,9 +293,11 @@ function SpaceOAuthCallbackContent() {
                 ? t('account.bindSpaceSuccess')
                 : t('common.spaceLoginSuccess'))}
             {status === 'error' &&
-              (isBindMode
-                ? t('account.bindSpaceFailed')
-                : t('common.spaceLoginError'))}
+              (terminalErrorCode
+                ? t(`account.${terminalErrorCode}Title`)
+                : isBindMode
+                  ? t('account.bindSpaceFailed')
+                  : t('common.spaceLoginError'))}
           </CardTitle>
           <CardDescription>
             {status === 'loading' &&
diff --git a/web/src/app/home/components/models-dialog/ModelsPanel.tsx b/web/src/app/home/components/models-dialog/ModelsPanel.tsx
index 22c3525a6..d04e041b4 100644
--- a/web/src/app/home/components/models-dialog/ModelsPanel.tsx
+++ b/web/src/app/home/components/models-dialog/ModelsPanel.tsx
@@ -25,6 +25,7 @@ import {
 import { CustomApiError } from '@/app/infra/entities/common';
 import { PanelBody } from '../settings-dialog/panel-layout';
 import { useCurrentWorkspace } from '@/app/infra/http';
+import type { WorkspaceSpaceBilling } from '@/app/infra/entities/workspace';
 
 interface ModelsPanelProps {
   // True when this panel is the active section and the dialog is open.
@@ -89,8 +90,8 @@ export default function ModelsPanel({
     currentWorkspace?.permissions.includes('provider_secret.manage') ?? false;
 
   const [providers, setProviders] = useState<ModelProvider[]>([]);
-  const [accountType, setAccountType] = useState<'local' | 'space'>('local');
-  const [spaceCredits, setSpaceCredits] = useState<number | null>(null);
+  const [spaceBilling, setSpaceBilling] =
+    useState<WorkspaceSpaceBilling | null>(null);
 
   // Expanded providers and their models
   const [expandedProviders, setExpandedProviders] = useState<Set<string>>(
@@ -144,7 +145,7 @@ export default function ModelsPanel({
 
   useEffect(() => {
     if (active) {
-      loadUserInfo();
+      loadWorkspaceBilling();
       loadProviders();
       loadRequesterSupportTypes();
     }
@@ -167,16 +168,11 @@ export default function ModelsPanel({
     }
   }, [providersLoaded, providers]);
 
-  async function loadUserInfo() {
+  async function loadWorkspaceBilling() {
     try {
-      const userInfo = await httpClient.getUserInfo();
-      setAccountType(userInfo.account_type);
-      if (userInfo.account_type === 'space') {
-        const creditsInfo = await httpClient.getSpaceCredits();
-        setSpaceCredits(creditsInfo.credits);
-      }
+      setSpaceBilling(await httpClient.getWorkspaceSpaceBilling());
     } catch {
-      setAccountType('local');
+      setSpaceBilling(null);
     }
   }
 
@@ -546,8 +542,9 @@ export default function ModelsPanel({
         isExpanded={expandedProviders.has(provider.uuid)}
         isLoading={loadingProviders.has(provider.uuid)}
         models={providerModels[provider.uuid]}
-        accountType={accountType}
-        spaceCredits={spaceCredits}
+        isWorkspaceOwner={currentWorkspace?.membership.role === 'owner'}
+        ownerSpaceBound={spaceBilling?.owner_space_bound ?? false}
+        spaceCredits={spaceBilling?.credits ?? null}
         addModelPopoverOpen={addModelPopoverOpen}
         editModelPopoverOpen={editModelPopoverOpen}
         deleteConfirmOpen={deleteConfirmOpen}
diff --git a/web/src/app/home/components/models-dialog/components/ProviderCard.tsx b/web/src/app/home/components/models-dialog/components/ProviderCard.tsx
index 79d62b1ab..b771d77bc 100644
--- a/web/src/app/home/components/models-dialog/components/ProviderCard.tsx
+++ b/web/src/app/home/components/models-dialog/components/ProviderCard.tsx
@@ -44,7 +44,8 @@ interface ProviderCardProps {
   isExpanded: boolean;
   isLoading: boolean;
   models?: ProviderModels;
-  accountType: 'local' | 'space';
+  isWorkspaceOwner: boolean;
+  ownerSpaceBound: boolean;
   spaceCredits: number | null;
   // Popover states
   addModelPopoverOpen: string | null;
@@ -108,7 +109,8 @@ export default function ProviderCard({
   isExpanded,
   isLoading,
   models,
-  accountType,
+  isWorkspaceOwner,
+  ownerSpaceBound,
   spaceCredits,
   addModelPopoverOpen,
   editModelPopoverOpen,
@@ -198,7 +200,7 @@ export default function ProviderCard({
               </div>
             </div>
             <div className="flex items-center gap-1 ml-2 shrink-0">
-              {canManage && isLangBotModels && accountType !== 'space' && (
+              {isLangBotModels && isWorkspaceOwner && !ownerSpaceBound && (
                 <Button
                   variant="outline"
                   size="sm"
@@ -208,32 +210,40 @@ export default function ProviderCard({
                   }}
                 >
                   <LogIn className="h-4 w-4 mr-1" />
-                  {t('models.loginWithSpace')}
+                  {t('models.ownerMustBindSpace')}
                 </Button>
               )}
-              {isLangBotModels &&
-                accountType === 'space' &&
-                spaceCredits !== null && (
-                  <div className="flex items-center gap-1 border rounded-md px-2 h-8 text-sm mr-2">
-                    <span>
-                      {(spaceCredits / 5000).toFixed(2)} {t('models.credits')}
-                    </span>
-                    <Button
-                      variant="ghost"
-                      size="icon"
-                      className="h-5 w-5"
-                      onClick={(e) => {
-                        e.stopPropagation();
-                        window.open(
-                          `${systemInfo.cloud_service_url}/profile?tab=billing`,
-                          '_blank',
-                        );
-                      }}
-                    >
-                      <Plus className="h-3 w-3" />
-                    </Button>
-                  </div>
-                )}
+              {isLangBotModels && ownerSpaceBound && spaceCredits !== null && (
+                <div className="flex items-center gap-1 border rounded-md px-2 h-8 text-sm mr-2">
+                  <span>
+                    {(spaceCredits / 5000).toFixed(2)} {t('models.credits')}
+                  </span>
+                  <Button
+                    variant="ghost"
+                    size="icon"
+                    className="h-5 w-5"
+                    onClick={(e) => {
+                      e.stopPropagation();
+                      window.open(
+                        `${systemInfo.cloud_service_url}/profile?tab=billing`,
+                        '_blank',
+                      );
+                    }}
+                  >
+                    <Plus className="h-3 w-3" />
+                  </Button>
+                </div>
+              )}
+              {isLangBotModels && !isWorkspaceOwner && ownerSpaceBound && (
+                <span className="text-xs text-muted-foreground">
+                  {t('models.usesOwnerSpaceBilling')}
+                </span>
+              )}
+              {isLangBotModels && !isWorkspaceOwner && !ownerSpaceBound && (
+                <span className="text-xs text-muted-foreground">
+                  {t('models.ownerMustBindSpace')}
+                </span>
+              )}
               {canManage && !isLangBotModels && (
                 <>
                   <Button
diff --git a/web/src/app/infra/entities/workspace.ts b/web/src/app/infra/entities/workspace.ts
index 1806e63d8..a64fd0f07 100644
--- a/web/src/app/infra/entities/workspace.ts
+++ b/web/src/app/infra/entities/workspace.ts
@@ -35,6 +35,12 @@ export interface CurrentWorkspace {
   plan_name?: string | null;
 }
 
+export interface WorkspaceSpaceBilling {
+  credits: number | null;
+  owner_space_bound: boolean;
+  is_workspace_owner: boolean;
+}
+
 /** Account-scoped Workspace entry returned before a Workspace is selected. */
 export type WorkspaceBootstrapEntry = CurrentWorkspace;
 
diff --git a/web/src/app/infra/http/BackendClient.ts b/web/src/app/infra/http/BackendClient.ts
index 716077f9c..e1733eaff 100644
--- a/web/src/app/infra/http/BackendClient.ts
+++ b/web/src/app/infra/http/BackendClient.ts
@@ -69,6 +69,7 @@ import type {
   WorkspaceMembership,
   WorkspaceBootstrapResponse,
   WorkspaceRole,
+  WorkspaceSpaceBilling,
 } from '@/app/infra/entities/workspace';
 
 /**
@@ -1146,10 +1147,8 @@ export class BackendClient extends BaseHttpClient {
     return this.get('/api/v1/user/info', undefined, { skipWorkspace: true });
   }
 
-  public getSpaceCredits(): Promise<{ credits: number | null }> {
-    return this.get('/api/v1/user/space-credits', undefined, {
-      skipWorkspace: true,
-    });
+  public getWorkspaceSpaceBilling(): Promise<WorkspaceSpaceBilling> {
+    return this.get('/api/v1/user/space-credits');
   }
 
   public getAccountInfo(): Promise<{
diff --git a/web/src/app/invitations/accept/page.tsx b/web/src/app/invitations/accept/page.tsx
index c2252c70e..e8d412ecc 100644
--- a/web/src/app/invitations/accept/page.tsx
+++ b/web/src/app/invitations/accept/page.tsx
@@ -22,7 +22,6 @@ import type {
 } from '@/app/infra/entities/workspace';
 import {
   backendClient,
-  beginAuthenticatedSession,
   bootstrapWorkspaceSession,
   clearPendingInvitationToken,
   clearUserInfo,
@@ -168,10 +167,12 @@ export default function AcceptInvitationPage() {
         token,
         registration,
       );
-      beginAuthenticatedSession(
-        response.token,
-        registration?.email ?? view?.invitation.normalized_email,
-      );
+      if (registration) {
+        clearPendingInvitationToken();
+        toast.success(t('workspace.invitationAccepted'));
+        navigate('/login?invitation=1', { replace: true });
+        return;
+      }
       clearPendingInvitationToken();
       const workspaceResult = await bootstrapWorkspaceSession({
         preferredWorkspaceUuid: response.workspace_uuid,
@@ -218,13 +219,14 @@ export default function AcceptInvitationPage() {
     });
   }
 
-  function switchAccount() {
+  function logoutAndReturn() {
+    if (token) setPendingInvitationToken(token);
     clearUserInfo();
     if (typeof window !== 'undefined') {
       localStorage.removeItem('token');
       localStorage.removeItem('userEmail');
     }
-    navigate('/login?invitation=1&auto=space', { replace: true });
+    navigate('/login?invitation=1', { replace: true });
   }
 
   function returnToLogin() {
@@ -238,11 +240,6 @@ export default function AcceptInvitationPage() {
 
   const hasLoginToken =
     typeof window !== 'undefined' && Boolean(localStorage.getItem('token'));
-  const currentEmail =
-    typeof window !== 'undefined' ? localStorage.getItem('userEmail') : null;
-  const currentAccountMatches =
-    currentEmail?.trim().toLocaleLowerCase() ===
-    view?.invitation.normalized_email.toLocaleLowerCase();
 
   return (
     <div className="flex min-h-screen items-center justify-center bg-gray-50 p-4 dark:bg-neutral-900">
@@ -307,24 +304,13 @@ export default function AcceptInvitationPage() {
                 </div>
               )}
 
-              {hasLoginToken && currentAccountMatches ? (
-                <Button
-                  className="w-full"
-                  disabled={status === 'submitting'}
-                  onClick={() => void finishAcceptance()}
-                >
-                  {status === 'submitting' && (
-                    <Loader2 className="size-4 animate-spin" />
-                  )}
-                  {t('workspace.acceptAsCurrentAccount')}
-                </Button>
-              ) : hasLoginToken ? (
+              {hasLoginToken ? (
                 <div className="space-y-3">
                   <div className="rounded-lg border border-amber-300 bg-amber-50 p-3 text-sm text-amber-900 dark:bg-amber-950/30 dark:text-amber-100">
-                    {t('workspace.invitationEmailMismatch')}
+                    {t('workspace.authenticatedInvitationNotice')}
                   </div>
-                  <Button className="w-full" onClick={switchAccount}>
-                    {t('workspace.switchAccount')}
+                  <Button className="w-full" onClick={logoutAndReturn}>
+                    {t('workspace.logoutAndReturn')}
                   </Button>
                 </div>
               ) : passwordRegistrationEnabled ? (
diff --git a/web/src/i18n/locales/en-US.ts b/web/src/i18n/locales/en-US.ts
index 85fa8206e..668e17405 100644
--- a/web/src/i18n/locales/en-US.ts
+++ b/web/src/i18n/locales/en-US.ts
@@ -279,6 +279,10 @@ const enUS = {
     credits: 'Credits',
     loginWithSpace: 'Login with LangBot Account',
     loginToUseModels: 'Login with Space to use cloud models',
+    ownerMustBindSpace:
+      'The Workspace owner must connect Space for LangBot Models.',
+    usesOwnerSpaceBilling:
+      "Uses the Workspace owner's Space billing and credits.",
     noModels: 'No models configured',
     langbotModels: 'LangBot Models',
     spaceTrialTooltip:
@@ -1283,7 +1287,13 @@ const enUS = {
       'Invalid bind request. Please try again from account settings.',
     setPasswordHint: 'Set a password to login with email and password',
     spaceEmailMismatch:
-      'Space login email does not match the local account email',
+      'The Space login email does not match the local account email.',
+    space_account_not_registeredTitle: 'Account not registered',
+    space_account_not_registered:
+      'No local account is registered for this Space email. Ask the Workspace owner for an invitation.',
+    space_account_binding_requiredTitle: 'Space connection required',
+    space_account_binding_required:
+      'This local account must connect Space from Account settings before using Space login.',
   },
   workspace: {
     title: 'Workspace',
@@ -1339,6 +1349,9 @@ const enUS = {
     existingAccountLoginRequired:
       'An account already exists for this email. Sign in to continue.',
     acceptAsCurrentAccount: 'Accept with current account',
+    authenticatedInvitationNotice:
+      'Sign out first, then sign in with the invited account. Your invitation will be preserved.',
+    logoutAndReturn: 'Sign out and return to this invitation',
     switchAccount: 'Switch account',
     registerAndAccept: 'Create account and accept',
     alreadyHaveAccount: 'I already have an account',
diff --git a/web/src/i18n/locales/ja-JP.ts b/web/src/i18n/locales/ja-JP.ts
index def29b657..8591f8506 100644
--- a/web/src/i18n/locales/ja-JP.ts
+++ b/web/src/i18n/locales/ja-JP.ts
@@ -284,6 +284,10 @@ const jaJP = {
     credits: 'クレジット',
     loginWithSpace: 'LangBot アカウントでログイン',
     loginToUseModels: 'Space でログインしてクラウドモデルを使用',
+    ownerMustBindSpace:
+      'LangBot モデルを使うにはワークスペース所有者が Space を連携する必要があります。',
+    usesOwnerSpaceBilling:
+      'ワークスペース所有者の Space 課金とクレジットを使用します。',
     noModels: 'モデルがありません',
     langbotModels: 'LangBot モデル',
     spaceTrialTooltip:
@@ -1289,6 +1293,12 @@ const jaJP = {
       'パスワードを設定するとメールとパスワードでログインできます',
     spaceEmailMismatch:
       'Spaceログインのメールアドレスがローカルアカウントのメールアドレスと一致しません',
+    space_account_not_registeredTitle: 'アカウントが登録されていません',
+    space_account_not_registered:
+      'この Space メールアドレスのローカルアカウントはありません。ワークスペース所有者に招待を依頼してください。',
+    space_account_binding_requiredTitle: 'Space の連携が必要です',
+    space_account_binding_required:
+      'Space ログインを使用する前に、アカウント設定でこのローカルアカウントを Space に連携してください。',
   },
   workspace: {
     title: 'ワークスペース',
@@ -1340,6 +1350,9 @@ const jaJP = {
     existingAccountLoginRequired:
       'このメールアドレスのアカウントは既に存在します。ログインしてください。',
     acceptAsCurrentAccount: '現在のアカウントで承認',
+    authenticatedInvitationNotice:
+      '一度ログアウトし、招待されたアカウントでログインしてください。招待は保持されます。',
+    logoutAndReturn: 'ログアウトしてこの招待に戻る',
     switchAccount: 'アカウントを切り替える',
     registerAndAccept: 'アカウントを作成して承認',
     alreadyHaveAccount: 'アカウントを持っています',
diff --git a/web/src/i18n/locales/zh-Hans.ts b/web/src/i18n/locales/zh-Hans.ts
index 8699cef30..fa4d56911 100644
--- a/web/src/i18n/locales/zh-Hans.ts
+++ b/web/src/i18n/locales/zh-Hans.ts
@@ -267,6 +267,8 @@ const zhHans = {
     credits: '积分',
     loginWithSpace: '使用 LangBot 账号登录',
     loginToUseModels: '通过 Space 登录以使用云端模型',
+    ownerMustBindSpace: '工作区所有者需要绑定 Space 才能使用 LangBot 模型。',
+    usesOwnerSpaceBilling: '使用工作区所有者的 Space 计费与积分。',
     noModels: '暂无模型',
     langbotModels: 'LangBot 模型',
     spaceTrialTooltip:
@@ -1219,6 +1221,12 @@ const zhHans = {
     bindSpaceInvalidState: '无效的绑定请求，请从账户设置重新发起',
     setPasswordHint: '设置密码后可使用邮箱密码登录',
     spaceEmailMismatch: 'Space登录账号邮箱与本实例账号邮箱不匹配',
+    space_account_not_registeredTitle: '账户尚未注册',
+    space_account_not_registered:
+      '此 Space 邮箱尚无本地账户，请联系工作区所有者获取邀请。',
+    space_account_binding_requiredTitle: '需要绑定 Space',
+    space_account_binding_required:
+      '此本地账户必须先在账户设置中绑定 Space，才能使用 Space 登录。',
   },
   workspace: {
     title: '工作区',
@@ -1270,6 +1278,9 @@ const zhHans = {
     invitationEmailMismatch: '此邀请属于另一个邮箱地址。',
     existingAccountLoginRequired: '此邮箱已有账户，请登录后继续。',
     acceptAsCurrentAccount: '使用当前账户接受',
+    authenticatedInvitationNotice:
+      '请先退出，再使用受邀账户登录。邀请令牌会被保留。',
+    logoutAndReturn: '退出并返回此邀请',
     switchAccount: '切换账号',
     registerAndAccept: '创建账户并接受',
     alreadyHaveAccount: '我已有账户',
diff --git a/web/tests/unit/oss-account-space-billing.test.mjs b/web/tests/unit/oss-account-space-billing.test.mjs
new file mode 100644
index 000000000..963b78ba8
--- /dev/null
+++ b/web/tests/unit/oss-account-space-billing.test.mjs
@@ -0,0 +1,49 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import path from 'node:path';
+import test from 'node:test';
+import { fileURLToPath } from 'node:url';
+
+const root = path.resolve(
+  path.dirname(fileURLToPath(import.meta.url)),
+  '../..',
+);
+const read = (file) => fs.readFileSync(path.join(root, file), 'utf8');
+
+test('invited local registration returns to login instead of authenticating', () => {
+  const source = read('src/app/invitations/accept/page.tsx');
+  assert.doesNotMatch(
+    source,
+    /beginAuthenticatedSession\([\s\S]{0,120}response\.token/,
+  );
+  assert.match(source, /navigate\('\/login\?invitation=1'/);
+});
+
+test('authenticated invitation page offers logout while retaining invitation', () => {
+  const source = read('src/app/invitations/accept/page.tsx');
+  assert.match(source, /workspace\.logoutAndReturn/);
+  assert.match(source, /setPendingInvitationToken\(token\)/);
+});
+
+test('Space OAuth callback distinguishes unknown and unbound accounts by stable codes', () => {
+  const source = read('src/app/auth/space/callback/page.tsx');
+  assert.match(source, /space_account_not_registered/);
+  assert.match(source, /space_account_binding_required/);
+});
+
+test('models panel derives LangBot Models billing state from workspace owner', () => {
+  const source = read('src/app/home/components/models-dialog/ModelsPanel.tsx');
+  assert.match(source, /getWorkspaceSpaceBilling/);
+  assert.doesNotMatch(source, /getSpaceCredits\(\)/);
+  assert.match(source, /membership\.role === 'owner'/);
+});
+
+test('provider card represents owner and member owner-bound states explicitly', () => {
+  const source = read(
+    'src/app/home/components/models-dialog/components/ProviderCard.tsx',
+  );
+  assert.match(source, /isWorkspaceOwner/);
+  assert.match(source, /ownerSpaceBound/);
+  assert.match(source, /models\.ownerMustBindSpace/);
+  assert.match(source, /models\.usesOwnerSpaceBilling/);
+});