feat(frontend): hosted sign-in and OAuth settings for Cognito app clients

packages/api/src/adapter-aws/AwsUserPoolsAdapter.test.ts

@@ -23,6 +23,7 @@ import {
     ListUserPoolClientsCommand,
     ListUserPoolsCommand,
     ListUsersCommand,
+    UpdateUserPoolClientCommand,
     type CognitoIdentityProviderClient,
 } from '@aws-sdk/client-cognito-identity-provider'
 import {AwsUserPoolsAdapter} from './AwsUserPoolsAdapter'
@@ -409,3 +410,63 @@ describe('AwsUserPoolsAdapter user actions and groups', () => {
             .toEqual({outcome: 'challenge', challengeName: 'NEW_PASSWORD_REQUIRED'})
     })
 })
+
+describe('app client OAuth settings', () => {
+    const CLIENT_ID = '40808d60e188483d876bbbf646'
+    const stored = {
+        UserPoolId: POOL_ID, ClientId: CLIENT_ID, ClientName: 'notes-demo-web',
+        ExplicitAuthFlows: ['ALLOW_USER_PASSWORD_AUTH', 'ALLOW_REFRESH_TOKEN_AUTH'],
+        PreventUserExistenceErrors: 'ENABLED', RefreshTokenValidity: 30, EnableTokenRevocation: true,
+        SupportedIdentityProviders: ['COGNITO'],
+    }
+
+    function clientStub() {
+        return stubCognito((command) => {
+            if (command instanceof DescribeUserPoolClientCommand) return {UserPoolClient: stored}
+            if (command instanceof UpdateUserPoolClientCommand) return {UserPoolClient: {...stored, ...command.input}}
+            return {}
+        })
+    }
+
+    test('reads a client with no OAuth set up', async () => {
+        const settings = await new AwsUserPoolsAdapter(clientStub().client).describeUserPoolClient(POOL_ID, CLIENT_ID)
+        expect(settings).toEqual({
+            clientId: CLIENT_ID, clientName: 'notes-demo-web', hasSecret: false,
+            explicitAuthFlows: ['ALLOW_USER_PASSWORD_AUTH', 'ALLOW_REFRESH_TOKEN_AUTH'],
+            callbackUrls: [], logoutUrls: [], oauthFlows: [], oauthScopes: [], identityProviders: ['COGNITO'],
+        })
+    })
+
+    test('turns on the code flow and sends the client\'s other settings back unchanged', async () => {
+        const {client, sent} = clientStub()
+        const settings = await new AwsUserPoolsAdapter(client).updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {
+            callbackUrls: ['http://localhost:4600/api/auth/callback', ' http://localhost:4600/api/auth/callback '],
+            logoutUrls: ['http://localhost:4600/'],
+            oauthFlows: ['code'], oauthScopes: ['openid', 'email'], identityProviders: ['COGNITO'],
+        })
+
+        const update = sent.find((command) => command instanceof UpdateUserPoolClientCommand) as UpdateUserPoolClientCommand
+        expect(update.input).toMatchObject({
+            ClientName: 'notes-demo-web', ExplicitAuthFlows: ['ALLOW_USER_PASSWORD_AUTH', 'ALLOW_REFRESH_TOKEN_AUTH'],
+            PreventUserExistenceErrors: 'ENABLED', RefreshTokenValidity: 30, EnableTokenRevocation: true,
+            CallbackURLs: ['http://localhost:4600/api/auth/callback'], LogoutURLs: ['http://localhost:4600/'],
+            AllowedOAuthFlows: ['code'], AllowedOAuthScopes: ['openid', 'email'], AllowedOAuthFlowsUserPoolClient: true,
+            SupportedIdentityProviders: ['COGNITO'],
+        })
+        expect(settings.oauthFlows).toEqual(['code'])
+    })
+
+    test('applies Cognito\'s rules before calling it', async () => {
+        const {client, sent} = clientStub()
+        const adapter = new AwsUserPoolsAdapter(client)
+        const valid = {callbackUrls: ['https://app.example/callback'], logoutUrls: [], oauthFlows: ['code' as const], oauthScopes: ['openid'], identityProviders: ['COGNITO']}
+
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, callbackUrls: ['http://app.example/callback']})).rejects.toThrow(/https/)
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, callbackUrls: ['https://app.example/#done']})).rejects.toThrow(/fragment/)
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, callbackUrls: []})).rejects.toThrow(/callback URL/)
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, oauthScopes: []})).rejects.toThrow(/scope/)
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, oauthFlows: ['code', 'client_credentials']})).rejects.toThrow(ValidationError)
+        await expect(adapter.updateUserPoolClientOAuth(POOL_ID, CLIENT_ID, {...valid, oauthFlows: ['client_credentials']})).rejects.toThrow(/secret/)
+        expect(sent.some((command) => command instanceof UpdateUserPoolClientCommand)).toBe(false)
+    })
+})

packages/api/src/adapter-aws/AwsUserPoolsAdapter.ts

@@ -24,11 +24,13 @@ import {
     ListUserPoolClientsCommand,
     ListUserPoolsCommand,
     ListUsersCommand,
+    UpdateUserPoolClientCommand,
     type AttributeType,
     type CognitoIdentityProviderClient,
     type GroupType,
     type PasswordPolicyType,
     type UserPoolClientDescription,
+    type UserPoolClientType,
     type UserPoolDescriptionType,
     type UserPoolType,
     type UserType,
@@ -38,6 +40,7 @@ import {ConflictError, RuntimeError, ValidationError} from '../cloud-spi/errors'
 import {
     USER_POOL_GROUP_NAME_PATTERN,
     USER_POOL_NAME_PATTERN,
+    USER_POOL_OAUTH_FLOWS,
     USER_POOL_PASSWORD_POLICIES,
     USER_POOL_SIGN_IN,
     awsUserPoolsSchema,
@@ -49,7 +52,10 @@ import type {
     CreateUserPoolGroupInput,
     ResourceQuery,
     ServiceSchema,
+    UpdateUserPoolClientOAuthInput,
+    UserPoolClientSettings,
     UserPoolGroup,
+    UserPoolOAuthFlow,
     UserPoolSignInTestInput,
     UserPoolSignInTestResult,
     UserPoolUserAction,
@@ -285,6 +291,54 @@ export class AwsUserPoolsAdapter implements CloudServiceAdapter {
         }
     }
 
+    async describeUserPoolClient(poolId: string, clientId: string): Promise<UserPoolClientSettings> {
+        return toClientSettings(await this.fetchClient(poolId, clientId))
+    }
+
+    /**
+     * Changes the settings the hosted login and OAuth endpoints use. UpdateUserPoolClient
+     * resets every setting it is not given, so the client's other settings are sent back as they are.
+     */
+    async updateUserPoolClientOAuth(poolId: string, clientId: string, input: UpdateUserPoolClientOAuthInput): Promise<UserPoolClientSettings> {
+        const settings = validateOAuthSettings(input)
+        const current = await this.fetchClient(poolId, clientId)
+        if (settings.oauthFlows.includes('client_credentials') && !current.ClientSecret) {
+            throw new ValidationError('The client_credentials flow needs an app client with a secret')
+        }
+        const res = await this.cognito.send(new UpdateUserPoolClientCommand({
+            UserPoolId: poolId,
+            ClientId: clientId,
+            ClientName: current.ClientName,
+            RefreshTokenValidity: current.RefreshTokenValidity,
+            AccessTokenValidity: current.AccessTokenValidity,
+            IdTokenValidity: current.IdTokenValidity,
+            TokenValidityUnits: current.TokenValidityUnits,
+            ReadAttributes: current.ReadAttributes,
+            WriteAttributes: current.WriteAttributes,
+            ExplicitAuthFlows: current.ExplicitAuthFlows,
+            DefaultRedirectURI: current.DefaultRedirectURI && settings.callbackUrls.includes(current.DefaultRedirectURI) ? current.DefaultRedirectURI : undefined,
+            AnalyticsConfiguration: current.AnalyticsConfiguration,
+            PreventUserExistenceErrors: current.PreventUserExistenceErrors,
+            EnableTokenRevocation: current.EnableTokenRevocation,
+            EnablePropagateAdditionalUserContextData: current.EnablePropagateAdditionalUserContextData,
+            AuthSessionValidity: current.AuthSessionValidity,
+            RefreshTokenRotation: current.RefreshTokenRotation,
+            CallbackURLs: settings.callbackUrls,
+            LogoutURLs: settings.logoutUrls,
+            AllowedOAuthFlows: settings.oauthFlows,
+            AllowedOAuthScopes: settings.oauthScopes,
+            AllowedOAuthFlowsUserPoolClient: settings.oauthFlows.length > 0,
+            SupportedIdentityProviders: settings.identityProviders,
+        }))
+        return toClientSettings(res.UserPoolClient ?? current)
+    }
+
+    private async fetchClient(poolId: string, clientId: string): Promise<UserPoolClientType> {
+        const res = await this.cognito.send(new DescribeUserPoolClientCommand({UserPoolId: poolId, ClientId: requiredString(clientId, 'clientId')}))
+        if (!res.UserPoolClient) throw new RuntimeError(`Cognito returned no app client ${clientId}`)
+        return res.UserPoolClient
+    }
+
     private async listGroupsForUser(poolId: string, username: string): Promise<string[]> {
         return listGroupNamesForUser(this.cognito, poolId, username)
     }
@@ -497,6 +551,66 @@ function lambdaTriggersOf(config: UserPoolType['LambdaConfig']): LambdaTrigger[]
     })
 }
 
+function toClientSettings(client: UserPoolClientType): UserPoolClientSettings {
+    return {
+        clientId: client.ClientId ?? '',
+        clientName: client.ClientName ?? '',
+        hasSecret: Boolean(client.ClientSecret),
+        explicitAuthFlows: client.ExplicitAuthFlows ?? [],
+        callbackUrls: client.CallbackURLs ?? [],
+        logoutUrls: client.LogoutURLs ?? [],
+        oauthFlows: client.AllowedOAuthFlowsUserPoolClient ? (client.AllowedOAuthFlows ?? []).filter(isOAuthFlow) : [],
+        oauthScopes: client.AllowedOAuthScopes ?? [],
+        identityProviders: client.SupportedIdentityProviders ?? [],
+    }
+}
+
+function isOAuthFlow(value: string): value is UserPoolOAuthFlow {
+    return (USER_POOL_OAUTH_FLOWS as readonly string[]).includes(value)
+}
+
+/** Cognito's own rules for these settings, checked here so the form can say what is wrong. */
+function validateOAuthSettings(input: UpdateUserPoolClientOAuthInput): UpdateUserPoolClientOAuthInput {
+    const callbackUrls = urlList(input?.callbackUrls, 'Callback URL')
+    const logoutUrls = urlList(input.logoutUrls, 'Sign-out URL')
+    const oauthFlows = stringList(input.oauthFlows, 'oauthFlows')
+    const unknown = oauthFlows.find((flow) => !isOAuthFlow(flow))
+    if (unknown) throw new ValidationError(`Unknown OAuth flow ${unknown}`)
+    if (oauthFlows.includes('client_credentials') && oauthFlows.length > 1) {
+        throw new ValidationError('client_credentials cannot be combined with the code or implicit flows')
+    }
+    if ((oauthFlows.includes('code') || oauthFlows.includes('implicit')) && callbackUrls.length === 0) {
+        throw new ValidationError('Add at least one callback URL for the code or implicit flow')
+    }
+    const oauthScopes = stringList(input.oauthScopes, 'oauthScopes')
+    if (oauthFlows.length > 0 && oauthScopes.length === 0) throw new ValidationError('Choose at least one OAuth scope')
+    const identityProviders = stringList(input.identityProviders, 'identityProviders')
+    return {callbackUrls, logoutUrls, oauthFlows: oauthFlows as UserPoolOAuthFlow[], oauthScopes, identityProviders}
+}
+
+function stringList(value: unknown, field: string): string[] {
+    if (!Array.isArray(value) || value.some((entry) => typeof entry !== 'string')) throw new ValidationError(`${field} must be a list of strings`)
+    return [...new Set(value.map((entry: string) => entry.trim()).filter(Boolean))]
+}
+
+// Cognito accepts https URLs, and http only for localhost; fragments are never allowed.
+function urlList(value: unknown, label: string): string[] {
+    return stringList(value, label).map((entry) => {
+        let url: URL
+        try {
+            url = new URL(entry)
+        } catch {
+            throw new ValidationError(`${label} ${entry} is not a valid URL`)
+        }
+        const local = url.hostname === 'localhost' || url.hostname === '127.0.0.1'
+        if (url.protocol !== 'https:' && !(url.protocol === 'http:' && local)) {
+            throw new ValidationError(`${label} ${entry} must use https (http is allowed only for localhost)`)
+        }
+        if (url.hash || entry.includes('#')) throw new ValidationError(`${label} ${entry} must not contain a fragment`)
+        return entry
+    })
+}
+
 function toUserItem(
     username: string | undefined,
     attributes: AttributeType[] | undefined,

packages/api/src/cloud-spi/types.ts

@@ -178,6 +178,8 @@ export type UserPoolActionName =
     | 'createGroup'
     | 'deleteGroup'
     | 'testSignIn'
+    | 'describeClient'
+    | 'updateClientOAuth'
 export type CapabilityStatus = 'available' | 'blocked' | 'partial' | 'coming_soon'
 
 export interface CapabilitySchema<TAction extends string> {
@@ -453,6 +455,29 @@ export interface UserPoolSignInTestInput {
 }
 
 /** Decoded claims only: the console shows what a sign-in yields without handing out tokens. */
+export type UserPoolOAuthFlow = 'code' | 'implicit' | 'client_credentials'
+
+/** The app client settings that decide how the hosted login and OAuth endpoints treat it. */
+export interface UserPoolClientSettings {
+    clientId: string
+    clientName: string
+    hasSecret: boolean
+    explicitAuthFlows: string[]
+    callbackUrls: string[]
+    logoutUrls: string[]
+    oauthFlows: UserPoolOAuthFlow[]
+    oauthScopes: string[]
+    identityProviders: string[]
+}
+
+export interface UpdateUserPoolClientOAuthInput {
+    callbackUrls: string[]
+    logoutUrls: string[]
+    oauthFlows: UserPoolOAuthFlow[]
+    oauthScopes: string[]
+    identityProviders: string[]
+}
+
 export type UserPoolSignInTestResult =
     | {outcome: 'signed-in'; expiresIn: number | null; idToken: Record<string, unknown>; accessToken: Record<string, unknown>}
     | {outcome: 'challenge'; challengeName: string}
@@ -970,6 +995,8 @@ export interface CloudServiceAdapter {
     createUserPoolGroup?(poolId: string, input: CreateUserPoolGroupInput): Promise<UserPoolGroup>
     deleteUserPoolGroup?(poolId: string, groupName: string): Promise<void>
     testUserPoolSignIn?(poolId: string, input: UserPoolSignInTestInput): Promise<UserPoolSignInTestResult>
+    describeUserPoolClient?(poolId: string, clientId: string): Promise<UserPoolClientSettings>
+    updateUserPoolClientOAuth?(poolId: string, clientId: string, input: UpdateUserPoolClientOAuthInput): Promise<UserPoolClientSettings>
     /** Clears the provider's locally captured email inbox, if it exposes one. */
     clearEmailInbox?(): Promise<void>
     // AppConfig nested resources, keyed by the ids the provider needs. Inspect

packages/api/src/cloud-spi/userPoolsSchema.ts

@@ -81,6 +81,8 @@ export function awsUserPoolsSchema(): ServiceSchema {
                 {name: 'createGroup', label: 'Create group', enabled: true, status: 'available', runtimeRequired: true},
                 {name: 'deleteGroup', label: 'Delete group', enabled: true, status: 'available', runtimeRequired: true},
                 {name: 'testSignIn', label: 'Test sign-in', enabled: true, status: 'available', runtimeRequired: true},
+                {name: 'describeClient', label: 'Show app client settings', enabled: true, status: 'available', runtimeRequired: true},
+                {name: 'updateClientOAuth', label: 'Change hosted sign-in and OAuth settings', enabled: true, status: 'available', runtimeRequired: true},
             ],
         },
         filters: userPoolFilters,
@@ -92,6 +94,10 @@ export function awsUserPoolsSchema(): ServiceSchema {
     }
 }
 
+export const USER_POOL_OAUTH_FLOWS = ['code', 'implicit', 'client_credentials'] as const
+/** Scopes every pool offers; resource servers can add their own. */
+export const USER_POOL_STANDARD_SCOPES = ['openid', 'email', 'phone', 'profile', 'aws.cognito.signin.user.admin'] as const
+
 export function userPoolsSchemaFor(cloud: CloudProvider): ServiceSchema | null {
     return cloud === 'aws' ? awsUserPoolsSchema() : null
 }

packages/api/src/cloudProxy.test.ts

@@ -54,6 +54,8 @@ const METHOD_FOR_USER_POOL_ACTION: Record<UserPoolActionName, keyof CloudService
     createGroup: 'createUserPoolGroup',
     deleteGroup: 'deleteUserPoolGroup',
     testSignIn: 'testUserPoolSignIn',
+    describeClient: 'describeUserPoolClient',
+    updateClientOAuth: 'updateUserPoolClientOAuth',
 }
 
 const registry = createCloudAdapterRegistry()

packages/api/src/routes/clouds.test.ts

@@ -747,6 +747,28 @@ describe('cloud schema routes', () => {
         ])
     })
 
+    test('reads and updates an app client\'s OAuth settings', async () => {
+        const settings = {clientId: 'c1', clientName: 'web', hasSecret: false, explicitAuthFlows: [], callbackUrls: [], logoutUrls: [], oauthFlows: [], oauthScopes: [], identityProviders: ['COGNITO']}
+        const calls: unknown[] = []
+        const app = appWithRoutes([mockAdapter('aws', {
+            service: 'userpools',
+            schema: awsUserPoolsSchema,
+            describeUserPoolClient: async () => settings,
+            updateUserPoolClientOAuth: async (poolId, clientId, input) => {
+                calls.push([poolId, clientId, input])
+                return {...settings, ...input}
+            },
+        })])
+        const base = '/api/clouds/aws/services/userpools/resources/us-east-1_x/clients/c1'
+        const input = {callbackUrls: ['http://localhost:4600/cb'], logoutUrls: [], oauthFlows: ['code'], oauthScopes: ['openid'], identityProviders: ['COGNITO']}
+
+        expect(await (await app.request(base)).json()).toEqual(settings)
+        const updated = await app.request(`${base}/oauth`, {method: 'PUT', headers: {'content-type': 'application/json'}, body: JSON.stringify(input)})
+        expect(updated.status).toBe(200)
+        expect((await updated.json()).oauthFlows).toEqual(['code'])
+        expect(calls).toEqual([['us-east-1_x', 'c1', input]])
+    })
+
     test('clears the SES mailbox through the email adapter', async () => {
         let cleared = false
         const app = appWithRoutes([mockAdapter('aws', {

packages/api/src/routes/clouds.ts

@@ -447,6 +447,20 @@ export function createCloudRoutes(injectedService?: CloudProxyService) {
         return withRuntime(c, async () => c.json(await svc(c).testUserPoolSignIn(cloud, c.req.param('id'), await c.req.json())))
     })
 
+    app.get('/:cloud/services/userpools/resources/:id/clients/:clientId', async (c) => {
+        const cloud = c.req.param('cloud') as CloudProvider
+        if (!isCloudProvider(cloud)) return c.json({error: 'Unknown cloud'}, 404)
+
+        return withRuntime(c, async () => c.json(await svc(c).describeUserPoolClient(cloud, c.req.param('id'), c.req.param('clientId'))))
+    })
+
+    app.put('/:cloud/services/userpools/resources/:id/clients/:clientId/oauth', async (c) => {
+        const cloud = c.req.param('cloud') as CloudProvider
+        if (!isCloudProvider(cloud)) return c.json({error: 'Unknown cloud'}, 404)
+
+        return withRuntime(c, async () => c.json(await svc(c).updateUserPoolClientOAuth(cloud, c.req.param('id'), c.req.param('clientId'), await c.req.json())))
+    })
+
     app.get('/:cloud/services/k8s/resources/:id/nodegroups', async (c) => {
         const cloud = c.req.param('cloud') as CloudProvider
         if (!isCloudProvider(cloud)) return c.json({error: 'Unknown cloud'}, 404)

packages/api/src/service/CloudProxyService.ts

@@ -81,6 +81,8 @@ import type {
     UserPoolGroup,
     UserPoolSignInTestInput,
     UserPoolSignInTestResult,
+    UserPoolClientSettings,
+    UpdateUserPoolClientOAuthInput,
     UserPoolUserAction,
 } from '../cloud-spi/types'
 import type {
@@ -831,6 +833,18 @@ export class CloudProxyService {
         return adapter.testUserPoolSignIn(poolId, input)
     }
 
+    async describeUserPoolClient(cloud: CloudProvider, poolId: string, clientId: string): Promise<UserPoolClientSettings> {
+        const adapter = this.requireAdapter(cloud, 'userpools')
+        if (!adapter.describeUserPoolClient) throw new NotSupportedError(`App client settings are not supported for ${cloud}/userpools`)
+        return adapter.describeUserPoolClient(poolId, clientId)
+    }
+
+    async updateUserPoolClientOAuth(cloud: CloudProvider, poolId: string, clientId: string, input: UpdateUserPoolClientOAuthInput): Promise<UserPoolClientSettings> {
+        const adapter = this.requireAdapter(cloud, 'userpools')
+        if (!adapter.updateUserPoolClientOAuth) throw new NotSupportedError(`App client settings are not supported for ${cloud}/userpools`)
+        return adapter.updateUserPoolClientOAuth(poolId, clientId, input)
+    }
+
     async listKubernetesNodegroups(cloud: CloudProvider, clusterId: string): Promise<KubernetesNodegroup[]> {
         const adapter = this.requireAdapter(cloud, 'k8s')
         if (!adapter.listKubernetesNodegroups) throw new NotSupportedError(`Nodegroups are not supported for ${cloud}/k8s`)

packages/frontend/src/api/api.ts

@@ -139,6 +139,10 @@ export const apiEndpointKeys = {
         delete: "clouds.services.userpools.groups.delete",
       },
       signInTest: "clouds.services.userpools.sign-in-test",
+      client: {
+        get: "clouds.services.userpools.clients.get",
+        updateOAuth: "clouds.services.userpools.clients.update-oauth",
+      },
     },
     k8s: {
       nodegroups: {
@@ -882,6 +886,20 @@ export const endpointRegistry: EndpointRegistry = new Map([
       method: "POST",
     },
   ],
+  [
+    apiEndpointKeys.clouds.userpools.client.get,
+    {
+      path: "/clouds/:cloud/services/userpools/resources/:id/clients/:clientId",
+      method: "GET",
+    },
+  ],
+  [
+    apiEndpointKeys.clouds.userpools.client.updateOAuth,
+    {
+      path: "/clouds/:cloud/services/userpools/resources/:id/clients/:clientId/oauth",
+      method: "PUT",
+    },
+  ],
   [
     apiEndpointKeys.clouds.k8s.nodegroups.list,
     {

packages/frontend/src/api/cloudProxyClient.ts

@@ -31,6 +31,8 @@ import type {
   UserPoolGroup,
   UserPoolSignInTestInput,
   UserPoolSignInTestResult,
+  UserPoolClientSettings,
+  UpdateUserPoolClientOAuthInput,
   UserPoolUserAction,
   LogsInsightsQueryInput,
   LogsInsightsQueryResult,
@@ -1474,6 +1476,34 @@ export async function testUserPoolSignIn(
   return res.data;
 }
 
+export async function describeUserPoolClient(
+  cloud: CloudProvider,
+  poolId: string,
+  clientId: string,
+  signal?: AbortSignal,
+): Promise<UserPoolClientSettings> {
+  const res = await apiClient.call<UserPoolClientSettings>(
+    apiEndpointKeys.clouds.userpools.client.get,
+    requestOptions(cloud, "userpools", { signal }),
+    { cloud, id: poolId, clientId },
+  );
+  return res.data;
+}
+
+export async function updateUserPoolClientOAuth(
+  cloud: CloudProvider,
+  poolId: string,
+  clientId: string,
+  input: UpdateUserPoolClientOAuthInput,
+): Promise<UserPoolClientSettings> {
+  const res = await apiClient.call<UserPoolClientSettings, UpdateUserPoolClientOAuthInput>(
+    apiEndpointKeys.clouds.userpools.client.updateOAuth,
+    requestOptions(cloud, "userpools", { body: input }),
+    { cloud, id: poolId, clientId },
+  );
+  return res.data;
+}
+
 export async function putFlatItem(
   cloud: CloudProvider,
   service: CloudServiceType,

packages/frontend/src/components/CognitoAppClientSettings.tsx

@@ -0,0 +1,145 @@
+import {X} from 'lucide-react'
+import {useMutation, useQuery, useQueryClient} from '@tanstack/react-query'
+import {useEffect, useState} from 'react'
+import {describeUserPoolClient, updateUserPoolClientOAuth} from '@/api/cloudProxyClient'
+import {useAccountId} from '@/lib/accountStore'
+import type {UserPoolClientSettings, UserPoolOAuthFlow} from '@/types/resource'
+
+type Props = {
+    poolId: string
+    clientId: string
+    runtimeReachable: boolean
+    onClose: () => void
+}
+
+const FLOWS: {flow: UserPoolOAuthFlow; label: string; hint: string}[] = [
+    {flow: 'code', label: 'Authorization code', hint: 'Recommended for web and mobile apps, with PKCE.'},
+    {flow: 'implicit', label: 'Implicit', hint: 'Legacy: tokens come back in the URL.'},
+    {flow: 'client_credentials', label: 'Client credentials', hint: 'Machine-to-machine. Needs a client secret.'},
+]
+const STANDARD_SCOPES = ['openid', 'email', 'phone', 'profile', 'aws.cognito.signin.user.admin']
+const COGNITO = 'COGNITO'
+
+type Draft = {callbackUrls: string; logoutUrls: string; oauthFlows: UserPoolOAuthFlow[]; oauthScopes: string[]; identityProviders: string[]}
+
+export function CognitoAppClientSettings({poolId, clientId, runtimeReachable, onClose}: Props) {
+    const accountId = useAccountId()
+    const queryClient = useQueryClient()
+    const clientKey = ['cognito-client', accountId, poolId, clientId]
+    const [draft, setDraft] = useState<Draft | null>(null)
+    const [notice, setNotice] = useState('')
+
+    const clientQuery = useQuery({
+        queryKey: clientKey,
+        queryFn: ({signal}) => describeUserPoolClient('aws', poolId, clientId, signal),
+        enabled: runtimeReachable,
+    })
+    const client = clientQuery.data
+
+    useEffect(() => {
+        if (client) setDraft(draftFrom(client))
+    }, [client])
+
+    const saveMutation = useMutation({
+        mutationFn: (value: Draft) => updateUserPoolClientOAuth('aws', poolId, clientId, {
+            callbackUrls: lines(value.callbackUrls),
+            logoutUrls: lines(value.logoutUrls),
+            oauthFlows: value.oauthFlows,
+            oauthScopes: value.oauthScopes,
+            identityProviders: value.identityProviders,
+        }),
+        onSuccess: (saved) => {
+            queryClient.setQueryData(clientKey, saved)
+            setNotice(saved.oauthFlows.includes('code') && saved.identityProviders.includes(COGNITO)
+                ? 'Saved. Apps using this client can now send users to the hosted login page.'
+                : 'Saved.')
+        },
+    })
+
+    const disabled = !runtimeReachable || saveMutation.isPending
+    const scopes = draft ? [...STANDARD_SCOPES, ...draft.oauthScopes.filter((scope) => !STANDARD_SCOPES.includes(scope))] : STANDARD_SCOPES
+    const otherProviders = draft?.identityProviders.filter((provider) => provider !== COGNITO) ?? []
+    const changed = Boolean(client && draft && JSON.stringify(normalized(draft)) !== JSON.stringify(normalized(draftFrom(client))))
+    const update = (patch: Partial<Draft>) => { setNotice(''); setDraft((current) => current && {...current, ...patch}) }
+    const toggle = <T extends string>(list: T[], value: T, on: boolean) => on ? [...list.filter((entry) => entry !== value), value] : list.filter((entry) => entry !== value)
+    const error = clientQuery.error ?? saveMutation.error
+
+    return <section className="cognito-user" aria-label={`App client ${client?.clientName || clientId}`}>
+        <div className="input-row resource-table-bar">
+            <div><p className="eyebrow">App client</p><strong>{client?.clientName || clientId}</strong></div>
+            <button className="icon-btn" type="button" title="Close" aria-label="Close app client settings" onClick={onClose}><X size={14}/></button>
+        </div>
+        {clientQuery.isLoading && <p className="muted padded">Loading app client</p>}
+        {client && draft && <form className="cognito-user-grid" aria-label="Hosted sign-in settings" onSubmit={(event) => { event.preventDefault(); saveMutation.mutate(draft) }}>
+            <dl className="cognito-facts">
+                <dt>Client ID</dt><dd className="mono">{client.clientId}</dd>
+                <dt>Client secret</dt><dd>{client.hasSecret ? 'Yes' : 'No (public client)'}</dd>
+                <dt>Sign-in flows</dt><dd>{client.explicitAuthFlows.length ? client.explicitAuthFlows.map((flow) => <code key={flow} className="cognito-flow">{flow.replace(/^ALLOW_/, '')}</code>) : '—'}</dd>
+            </dl>
+
+            <div>
+                <p className="eyebrow">Hosted sign-in</p>
+                <label className="cognito-check">
+                    <input type="checkbox" checked={draft.identityProviders.includes(COGNITO)} disabled={disabled} onChange={(event) => update({identityProviders: toggle(draft.identityProviders, COGNITO, event.target.checked)})}/>
+                    Hosted login page for this pool's users
+                </label>
+                {otherProviders.length > 0 && <p className="muted compact-text">Also signs in with: {otherProviders.map((provider) => <code key={provider}>{provider}</code>)}</p>}
+                <p className="eyebrow">OAuth flows</p>
+                {FLOWS.map(({flow, label, hint}) => (
+                    <label key={flow} className="cognito-check" title={hint}>
+                        <input type="checkbox" checked={draft.oauthFlows.includes(flow)} disabled={disabled || (flow === 'client_credentials' && !client.hasSecret)} onChange={(event) => update({oauthFlows: toggle(draft.oauthFlows, flow, event.target.checked)})}/>
+                        {label} <small className="muted">{hint}</small>
+                    </label>
+                ))}
+            </div>
+
+            <div>
+                <p className="eyebrow">Scopes</p>
+                {scopes.map((scope) => (
+                    <label key={scope} className="cognito-check">
+                        <input type="checkbox" checked={draft.oauthScopes.includes(scope)} disabled={disabled} onChange={(event) => update({oauthScopes: toggle(draft.oauthScopes, scope, event.target.checked)})}/>
+                        <code>{scope}</code>
+                    </label>
+                ))}
+            </div>
+
+            <div className="cognito-client-urls">
+                <label className="dynamic-field"><span>Callback URLs</span>
+                    <textarea className="textarea code-textarea small" rows={3} value={draft.callbackUrls} disabled={disabled} placeholder="http://localhost:3000/api/auth/callback" onChange={(event) => update({callbackUrls: event.target.value})}/>
+                    <small className="muted">One per line. Where Cognito sends users back with a code. https, or http for localhost.</small>
+                </label>
+                <label className="dynamic-field"><span>Sign-out URLs</span>
+                    <textarea className="textarea code-textarea small" rows={3} value={draft.logoutUrls} disabled={disabled} placeholder="http://localhost:3000/" onChange={(event) => update({logoutUrls: event.target.value})}/>
+                    <small className="muted">One per line. Allowed <code>logout_uri</code> values after sign-out.</small>
+                </label>
+                <div><button className="button primary" type="submit" disabled={disabled || !changed}>{saveMutation.isPending ? 'Saving' : 'Save settings'}</button></div>
+            </div>
+        </form>}
+        {notice && <p className="cognito-outcome cognito-outcome--ok" role="status">{notice}</p>}
+        {error instanceof Error && <p className="error-text compact-text" role="alert">{error.message}</p>}
+    </section>
+}
+
+function draftFrom(client: UserPoolClientSettings): Draft {
+    return {
+        callbackUrls: client.callbackUrls.join('\n'),
+        logoutUrls: client.logoutUrls.join('\n'),
+        oauthFlows: client.oauthFlows,
+        oauthScopes: client.oauthScopes,
+        identityProviders: client.identityProviders,
+    }
+}
+
+function normalized(draft: Draft) {
+    return {
+        callbackUrls: lines(draft.callbackUrls),
+        logoutUrls: lines(draft.logoutUrls),
+        oauthFlows: [...draft.oauthFlows].sort(),
+        oauthScopes: [...draft.oauthScopes].sort(),
+        identityProviders: [...draft.identityProviders].sort(),
+    }
+}
+
+function lines(value: string): string[] {
+    return value.split('\n').map((line) => line.trim()).filter(Boolean)
+}

packages/frontend/src/components/CognitoUsersPanel.test.tsx

@@ -17,6 +17,8 @@ const api = vi.hoisted(() => ({
     createUserPoolGroup: vi.fn(),
     deleteUserPoolGroup: vi.fn(),
     testUserPoolSignIn: vi.fn(),
+    describeUserPoolClient: vi.fn(),
+    updateUserPoolClientOAuth: vi.fn(),
 }))
 
 vi.mock('@/api/cloudProxyClient', () => api)
@@ -82,6 +84,32 @@ test('says when a pool has no Lambda triggers', async () => {
     expect(await screen.findByText('This pool runs no Lambda triggers.')).toBeInTheDocument()
 })
 
+test('turns on hosted sign-in for an app client', async () => {
+    const user = userEvent.setup()
+    const settings = {clientId: 'a8e5c7d38d3b4a1a97c9d822de', clientName: 'orders-users-client', hasSecret: false, explicitAuthFlows: ['ALLOW_REFRESH_TOKEN_AUTH'],
+        callbackUrls: [], logoutUrls: [], oauthFlows: [], oauthScopes: [], identityProviders: ['COGNITO']}
+    api.getCloudResource.mockResolvedValue(pool('email'))
+    api.describeUserPoolClient.mockResolvedValue(settings)
+    api.updateUserPoolClientOAuth.mockImplementation(async (_cloud, _pool, _client, input) => ({...settings, ...input}))
+    renderPanel()
+
+    await user.click(await screen.findByRole('button', {name: 'Manage app client orders-users-client'}))
+    const form = await screen.findByRole('form', {name: 'Hosted sign-in settings'})
+    expect(within(form).getByRole('checkbox', {name: /Client credentials/})).toBeDisabled()
+    await user.click(within(form).getByRole('checkbox', {name: /Authorization code/}))
+    await user.click(within(form).getByRole('checkbox', {name: 'openid'}))
+    await user.click(within(form).getByRole('checkbox', {name: 'email'}))
+    await user.type(within(form).getByLabelText(/Callback URLs/), 'http://localhost:4600/api/auth/callback')
+    await user.type(within(form).getByLabelText(/Sign-out URLs/), 'http://localhost:4600/')
+    await user.click(within(form).getByRole('button', {name: 'Save settings'}))
+
+    expect(api.updateUserPoolClientOAuth).toHaveBeenCalledWith('aws', summary.id, 'a8e5c7d38d3b4a1a97c9d822de', {
+        callbackUrls: ['http://localhost:4600/api/auth/callback'], logoutUrls: ['http://localhost:4600/'],
+        oauthFlows: ['code'], oauthScopes: ['openid', 'email'], identityProviders: ['COGNITO'],
+    })
+    expect(await screen.findByText(/can now send users to the hosted login page/)).toBeInTheDocument()
+})
+
 test('creates an email user who can sign in immediately', async () => {
     const user = userEvent.setup()
     api.getCloudResource.mockResolvedValue(pool('email'))

packages/frontend/src/components/CognitoUsersPanel.tsx

@@ -2,6 +2,7 @@ import {RefreshCw, Trash2} from 'lucide-react'
 import {useMutation, useQuery, useQueryClient} from '@tanstack/react-query'
 import {useEffect, useState} from 'react'
 import {deleteFlatItem, getCloudResource, listFlatItems, listUserPoolGroups, putFlatItem} from '@/api/cloudProxyClient'
+import {CognitoAppClientSettings} from '@/components/CognitoAppClientSettings'
 import {CognitoGroupsSection} from '@/components/CognitoGroupsSection'
 import {CognitoSignInTest} from '@/components/CognitoSignInTest'
 import {CognitoTriggersSection} from '@/components/CognitoTriggersSection'
@@ -25,6 +26,7 @@ export function CognitoUsersPanel({resource, runtimeReachable}: Props) {
     const [password, setPassword] = useState('')
     const [permanent, setPermanent] = useState(true)
     const [openUser, setOpenUser] = useState<string | null>(null)
+    const [openClient, setOpenClient] = useState<string | null>(null)
     const usersKey = ['cognito-users', accountId, resource?.id]
     const groupsKey = ['cognito-groups', accountId, resource?.id]
 
@@ -94,9 +96,14 @@ export function CognitoUsersPanel({resource, runtimeReachable}: Props) {
             <div><p className="eyebrow">App clients</p><span className="muted">Use a client ID with the pool ID to sign users in from your app</span></div>
         </div>
         {poolQuery.isSuccess && appClients.length === 0 && <p className="muted padded">This pool has no app clients.</p>}
-        {appClients.length > 0 && <div className="cognito-table"><table className="table"><thead><tr><th>Name</th><th>Client ID</th></tr></thead><tbody>{appClients.map((client) => (
+        {appClients.length > 0 && <div className="cognito-table"><table className="table"><thead><tr><th>Name</th><th>Client ID</th><th/></tr></thead><tbody>{appClients.map((client) => (
-            <tr key={client.clientId}><td>{client.clientName || '—'}</td><td><span className="copy-value mono">{client.clientId}<CopyValueButton value={client.clientId} label="Client ID"/></span></td></tr>
+            <tr key={client.clientId}>
+                <td>{client.clientName || '—'}</td>
+                <td><span className="copy-value mono">{client.clientId}<CopyValueButton value={client.clientId} label="Client ID"/></span></td>
+                <td className="cognito-row-actions"><button className="button" type="button" aria-expanded={openClient === client.clientId} aria-label={`Manage app client ${client.clientName || client.clientId}`} onClick={() => setOpenClient(openClient === client.clientId ? null : client.clientId)}>Manage</button></td>
+            </tr>
         ))}</tbody></table></div>}
+        {openClient && <CognitoAppClientSettings key={openClient} poolId={resource.id} clientId={openClient} runtimeReachable={runtimeReachable} onClose={() => setOpenClient(null)}/>}
 
         <CognitoTriggersSection pool={poolQuery.data ?? undefined}/>
 

packages/frontend/src/index.css

@@ -4395,6 +4395,21 @@ pre,
     margin-bottom: 8px;
 }
 
+.cognito-check small { flex-basis: 100%; padding-left: 24px; margin-top: -4px; }
+.cognito-check:has(small) { flex-wrap: wrap; row-gap: 0; }
+
+.cognito-flow { display: inline-block; margin: 0 6px 4px 0; }
+
+.cognito-client-urls {
+    grid-column: 1 / -1;
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
+    gap: 16px;
+    align-items: start;
+}
+
+.cognito-client-urls > div { align-self: end; }
+
 .delete-impact {
     color: var(--status-warn);
     font-size: 13px;

packages/frontend/src/types/resource.ts

@@ -302,6 +302,22 @@ export interface UserPoolSignInTestInput {
     password: string
 }
 
+export type UserPoolOAuthFlow = 'code' | 'implicit' | 'client_credentials'
+
+export interface UserPoolClientSettings {
+    clientId: string
+    clientName: string
+    hasSecret: boolean
+    explicitAuthFlows: string[]
+    callbackUrls: string[]
+    logoutUrls: string[]
+    oauthFlows: UserPoolOAuthFlow[]
+    oauthScopes: string[]
+    identityProviders: string[]
+}
+
+export type UpdateUserPoolClientOAuthInput = Pick<UserPoolClientSettings, 'callbackUrls' | 'logoutUrls' | 'oauthFlows' | 'oauthScopes' | 'identityProviders'>
+
 export type UserPoolSignInTestResult =
     | {outcome: 'signed-in'; expiresIn: number | null; idToken: Record<string, unknown>; accessToken: Record<string, unknown>}
     | {outcome: 'challenge'; challengeName: string}

packages/frontend/src/types/schema.ts

@@ -27,7 +27,7 @@ export type KubernetesActionName =
     | 'createFargateProfile'
     | 'deleteFargateProfile'
 export type ItemActionName = 'list' | 'get' | 'put' | 'delete' | 'query'
-export type UserPoolActionName = 'updateUser' | 'setUserGroups' | 'listGroups' | 'createGroup' | 'deleteGroup' | 'testSignIn'
+export type UserPoolActionName = 'updateUser' | 'setUserGroups' | 'listGroups' | 'createGroup' | 'deleteGroup' | 'testSignIn' | 'describeClient' | 'updateClientOAuth'
 export type CapabilityStatus = 'available' | 'blocked' | 'partial' | 'coming_soon'
 
 export interface CapabilitySchema<TAction extends string> {