diff --git a/src/langbot/pkg/api/http/controller/groups/user.py b/src/langbot/pkg/api/http/controller/groups/user.py
index 6b42d4ea3..5568047ca 100644
--- a/src/langbot/pkg/api/http/controller/groups/user.py
+++ b/src/langbot/pkg/api/http/controller/groups/user.py
@@ -322,6 +322,7 @@ class UserRouterGroup(group.RouterGroup):
             if cloud_mode:
                 capabilities['password_login_enabled'] = False
             capabilities['authenticated_invitation_acceptance_enabled'] = cloud_mode
+            capabilities['invitation_registration_enabled'] = not cloud_mode
             return self.success(data={'initialized': True, **capabilities})
 
         @self.route('/set-password', methods=['POST'], auth_type=group.AuthType.USER_TOKEN)
diff --git a/tests/integration/api/test_smoke.py b/tests/integration/api/test_smoke.py
index dfd5054f2..642efaf2b 100644
--- a/tests/integration/api/test_smoke.py
+++ b/tests/integration/api/test_smoke.py
@@ -307,6 +307,7 @@ class TestUserInitEndpoint:
         assert data['data'] == {
             'initialized': True,
             'authenticated_invitation_acceptance_enabled': False,
+            'invitation_registration_enabled': True,
             'password_login_enabled': True,
             'space_login_enabled': False,
         }
@@ -330,6 +331,28 @@ class TestUserInitEndpoint:
         assert data['data'] == {
             'initialized': True,
             'authenticated_invitation_acceptance_enabled': True,
+            'invitation_registration_enabled': False,
+            'password_login_enabled': False,
+            'space_login_enabled': True,
+        }
+
+    @pytest.mark.asyncio
+    async def test_account_info_enables_local_invitation_registration_for_oauth_only_oss(
+        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': False, 'space_login_enabled': True}
+        )
+
+        response = await quart_test_client.get('/api/v1/user/account-info')
+
+        assert response.status_code == 200
+        data = await response.get_json()
+        assert data['data'] == {
+            'initialized': True,
+            'authenticated_invitation_acceptance_enabled': False,
+            'invitation_registration_enabled': True,
             'password_login_enabled': False,
             'space_login_enabled': True,
         }
diff --git a/tests/integration/api/test_user_space_oauth.py b/tests/integration/api/test_user_space_oauth.py
index 9d22e5b3c..be0a9f021 100644
--- a/tests/integration/api/test_user_space_oauth.py
+++ b/tests/integration/api/test_user_space_oauth.py
@@ -312,6 +312,29 @@ async def test_space_credits_are_resolved_from_workspace_owner(space_oauth_api):
     application.space_service.get_credits.assert_awaited_once_with('owner@example.com')
 
 
+@pytest.mark.asyncio
+async def test_oss_local_only_owner_requires_space_binding_for_langbot_models(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=None)
+    )
+    application.space_service.get_credits = AsyncMock()
+
+    response = await client.get(
+        '/api/v1/user/space-credits',
+        headers={'Authorization': 'Bearer account-token', 'X-Workspace-Id': WORKSPACE_UUID},
+    )
+    payload = await response.get_json()
+
+    assert response.status_code == 200
+    assert payload['data'] == {
+        'credits': None,
+        'owner_space_bound': False,
+        'is_workspace_owner': True,
+    }
+    application.space_service.get_credits.assert_not_awaited()
+
+
 @pytest.mark.asyncio
 async def test_cloud_workspace_owner_is_always_space_bound_after_login(space_oauth_api):
     application, client = space_oauth_api
diff --git a/web/src/app/infra/http/BackendClient.ts b/web/src/app/infra/http/BackendClient.ts
index 1bfe1fcf2..07df4bf7c 100644
--- a/web/src/app/infra/http/BackendClient.ts
+++ b/web/src/app/infra/http/BackendClient.ts
@@ -1181,6 +1181,7 @@ export class BackendClient extends BaseHttpClient {
   public getAccountInfo(): Promise<{
     initialized: boolean;
     authenticated_invitation_acceptance_enabled?: boolean;
+    invitation_registration_enabled?: boolean;
     password_login_enabled?: boolean;
     space_login_enabled?: boolean;
   }> {
diff --git a/web/src/app/invitations/accept/page.tsx b/web/src/app/invitations/accept/page.tsx
index 0d83331b5..1d9591a54 100644
--- a/web/src/app/invitations/accept/page.tsx
+++ b/web/src/app/invitations/accept/page.tsx
@@ -91,7 +91,9 @@ export default function AcceptInvitationPage() {
   const [errorMessage, setErrorMessage] = useState('');
   const [password, setPassword] = useState('');
   const [confirmPassword, setConfirmPassword] = useState('');
-  const [passwordRegistrationEnabled, setPasswordRegistrationEnabled] =
+  const [invitationRegistrationEnabled, setInvitationRegistrationEnabled] =
+    useState(false);
+  const [invitationCapabilitiesLoaded, setInvitationCapabilitiesLoaded] =
     useState(false);
   const [
     authenticatedInvitationAcceptanceEnabled,
@@ -116,12 +118,16 @@ export default function AcceptInvitationPage() {
     backendClient
       .getAccountInfo()
       .then((info) => {
-        setPasswordRegistrationEnabled(info.password_login_enabled !== false);
+        setInvitationRegistrationEnabled(
+          info.invitation_registration_enabled ??
+            info.password_login_enabled !== false,
+        );
         setAuthenticatedInvitationAcceptanceEnabled(
           info.authenticated_invitation_acceptance_enabled === true,
         );
       })
-      .catch(() => setPasswordRegistrationEnabled(false));
+      .catch(() => setInvitationRegistrationEnabled(false))
+      .finally(() => setInvitationCapabilitiesLoaded(true));
     if (!invitationToken) {
       setErrorMessage(t('workspace.invitationMissing'));
       setStatus('error');
@@ -311,7 +317,11 @@ export default function AcceptInvitationPage() {
                 </div>
               )}
 
-              {hasLoginToken && authenticatedInvitationAcceptanceEnabled ? (
+              {!invitationCapabilitiesLoaded ? (
+                <div className="flex justify-center py-8">
+                  <Loader2 className="size-6 animate-spin" />
+                </div>
+              ) : hasLoginToken && authenticatedInvitationAcceptanceEnabled ? (
                 <Button
                   className="w-full"
                   disabled={status === 'submitting'}
@@ -331,7 +341,7 @@ export default function AcceptInvitationPage() {
                     {t('workspace.logoutAndReturn')}
                   </Button>
                 </div>
-              ) : passwordRegistrationEnabled ? (
+              ) : invitationRegistrationEnabled ? (
                 <>
                   <div className="space-y-2">
                     <label
diff --git a/web/tests/e2e/fixtures/langbot-api.ts b/web/tests/e2e/fixtures/langbot-api.ts
index 099ce70c6..1b4313a1a 100644
--- a/web/tests/e2e/fixtures/langbot-api.ts
+++ b/web/tests/e2e/fixtures/langbot-api.ts
@@ -503,6 +503,8 @@ async function handleBackendApi(route: Route, state: LangBotApiMockState) {
   if (path === '/api/v1/user/account-info') {
     return fulfillJson(route, {
       initialized: true,
+      authenticated_invitation_acceptance_enabled: false,
+      invitation_registration_enabled: true,
       password_login_enabled: true,
       space_login_enabled: false,
     });
diff --git a/web/tests/e2e/invitations.spec.ts b/web/tests/e2e/invitations.spec.ts
index b036838e2..d9213ad34 100644
--- a/web/tests/e2e/invitations.spec.ts
+++ b/web/tests/e2e/invitations.spec.ts
@@ -107,6 +107,101 @@ test('login preserves an explicit invitation email mismatch error', async ({
   await expect(page.getByText('Login successful')).toHaveCount(0);
 });
 
+test('an OAuth-only OSS instance registers the invited email with a local password', async ({
+  page,
+}) => {
+  let registration: { email?: string; password?: string } | undefined;
+  await installLangBotApiMocks(page, { authenticated: false });
+  await page.route('**/api/v1/user/account-info', async (route) => {
+    await new Promise((resolve) => setTimeout(resolve, 800));
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({
+        code: 0,
+        data: {
+          initialized: true,
+          authenticated_invitation_acceptance_enabled: false,
+          invitation_registration_enabled: true,
+          password_login_enabled: false,
+          space_login_enabled: true,
+        },
+        msg: 'ok',
+      }),
+    });
+  });
+  await page.route('**/api/v1/invitations/inspect', async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({
+        code: 0,
+        data: {
+          invitation: {
+            uuid: 'oss-local-registration',
+            workspace_uuid: 'workspace-playwright',
+            normalized_email: 'invited@example.com',
+            role: 'viewer',
+            status: 'pending',
+          },
+          workspace: {
+            uuid: 'workspace-playwright',
+            name: 'Playwright Workspace',
+          },
+        },
+        msg: 'ok',
+      }),
+    });
+  });
+  await page.route('**/api/v1/invitations/accept', async (route) => {
+    const body = JSON.parse(route.request().postData() || '{}') as {
+      registration?: { email?: string; password?: string };
+    };
+    registration = body.registration;
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({
+        code: 0,
+        data: {
+          login_required: true,
+          workspace_uuid: 'workspace-playwright',
+        },
+        msg: 'ok',
+      }),
+    });
+  });
+
+  await page.goto('/invitations/accept#token=oss-local-registration');
+
+  await expect(page.getByText('Playwright Workspace')).toBeVisible();
+  await expect(
+    page.getByRole('button', { name: 'Login with LangBot Account' }),
+  ).toHaveCount(0);
+  await expect(page.locator('#invite-email')).toHaveValue(
+    'invited@example.com',
+  );
+  await expect(page.locator('#invite-email')).toHaveAttribute('readonly', '');
+  await expect(page.locator('#invite-password')).toBeVisible();
+  await expect(page.locator('#invite-password-confirm')).toBeVisible();
+  await expect(
+    page.getByRole('button', { name: 'Create account and accept' }),
+  ).toBeVisible();
+  await expect(
+    page.getByRole('button', { name: 'Login with LangBot Account' }),
+  ).toHaveCount(0);
+
+  await page.locator('#invite-password').fill('invite-password-123');
+  await page.locator('#invite-password-confirm').fill('invite-password-123');
+  await page.getByRole('button', { name: 'Create account and accept' }).click();
+
+  await expect(page).toHaveURL(/\/login\?invitation=1$/);
+  expect(registration).toEqual({
+    email: 'invited@example.com',
+    password: 'invite-password-123',
+  });
+});
+
 test('an authenticated OSS invitation requires logout before registration', async ({
   page,
 }) => {
@@ -185,6 +280,7 @@ test('an authenticated Cloud Account can accept its invitation directly', async
         data: {
           initialized: true,
           authenticated_invitation_acceptance_enabled: true,
+          invitation_registration_enabled: false,
           password_login_enabled: false,
           space_login_enabled: true,
         },
diff --git a/web/tests/e2e/owner-space-billing.spec.ts b/web/tests/e2e/owner-space-billing.spec.ts
new file mode 100644
index 000000000..0c5f7c5e5
--- /dev/null
+++ b/web/tests/e2e/owner-space-billing.spec.ts
@@ -0,0 +1,63 @@
+import { expect, test } from '@playwright/test';
+
+import { installLangBotApiMocks } from './fixtures/langbot-api';
+
+test('an OSS local-only owner is prompted to bind before using LangBot Models', async ({
+  page,
+}) => {
+  await installLangBotApiMocks(page, { authenticated: true });
+  await page.route('**/api/v1/user/space-credits', (route) =>
+    route.fulfill({
+      contentType: 'application/json',
+      body: JSON.stringify({
+        code: 0,
+        data: {
+          credits: null,
+          owner_space_bound: false,
+          is_workspace_owner: true,
+        },
+        msg: 'ok',
+      }),
+    }),
+  );
+  await page.route('**/api/v1/provider/providers', (route) =>
+    route.fulfill({
+      contentType: 'application/json',
+      body: JSON.stringify({
+        code: 0,
+        data: {
+          providers: [
+            {
+              uuid: 'langbot-models-provider',
+              name: 'LangBot Models',
+              requester: 'space-chat-completions',
+              base_url: '',
+              api_keys: [],
+            },
+          ],
+        },
+        msg: 'ok',
+      }),
+    }),
+  );
+  await page.route('**/api/v1/provider/requesters**', (route) =>
+    route.fulfill({
+      contentType: 'application/json',
+      body: JSON.stringify({ code: 0, data: { requesters: [] }, msg: 'ok' }),
+    }),
+  );
+  await page.route('**/api/v1/provider/models/**', (route) =>
+    route.fulfill({
+      contentType: 'application/json',
+      body: JSON.stringify({ code: 0, data: { models: [] }, msg: 'ok' }),
+    }),
+  );
+
+  await page.goto('/home?action=showModelSettings');
+
+  await expect(
+    page.getByRole('button', {
+      name: 'The Workspace owner must connect a LangBot Account for LangBot Models.',
+    }),
+  ).toBeVisible();
+});