AWS Auth

AWSOfficialPublished by AWS

Skill
Tool integration
Cloud and DevOps
Apache-2.0
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From the author

Adds user authentication to web and mobile apps with Amazon Cognito (user pools and identity pools) and the AWS Amplify client auth libraries. Covers sign-up/sign-in flows and the login page (Cognito-hosted UI / managed login), MFA, password policies, OAuth 2.0 / OIDC flows (auth-code + PKCE, client credentials), social/SAML federation, tokens (ID/access/refresh, rotation, revocation, storage), Cognito Lambda triggers, identity pools (temp AWS creds), and gating API Gateway (or ALB) routes to signed-in users via Cognito/JWT authorizers. Applies when adding a login or sign-up page, configuring a user pool or app client, choosing user pool vs identity pool, wiring social/SAML, refreshing tokens, requiring sign-in on an API Gateway or ALB, or debugging redirect_uri/token/MFA/CORS/federation errors. Does NOT cover Amplify Gen2 backend definitions (defineAuth, npx ampx → aws-amplify), IAM/STS/Identity Center (→ aws-iam), or API Gateway/Lambda resource config beyond the authorizer (→ aws-serverless).

— the description by AWS

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides guidance on integrating Amazon Cognito user pools and identity pools into web and mobile applications. It covers the full lifecycle of authentication, including sign-up/sign-in flows, managed login, MFA, OAuth 2.0/OIDC standards, and token management. It also details how to secure API Gateway or ALB routes using Cognito authorizers and how to vend temporary AWS credentials to clients via identity pools. The skill emphasizes secure practices, such as using PKCE for public clients and avoiding common pitfalls like client secret exposure or improper identity pool role configuration.

What it does

Configures Amazon Cognito user pools for user directory and authentication management.
Implements OAuth 2.0 and OIDC flows, including authorization code grant with PKCE.
Secures API Gateway and ALB routes using Cognito/JWT authorizers.
Manages identity pools to provide temporary AWS credentials to authenticated clients.
Handles token lifecycle, including rotation, revocation, and secure storage.
Integrates social and SAML federation for external identity providers.

When to use it

When adding sign-up or login functionality to a web or mobile application.
When you need to gate API endpoints to ensure only authenticated users can access them.
When your client application requires direct access to AWS services like S3 or DynamoDB.
When configuring MFA, password policies, or custom authentication challenges.
When troubleshooting authentication errors like redirect mismatches, CORS issues, or token validation failures.

Advantages

Provides clear distinctions between user pools and identity pools to prevent common architectural errors.
Highlights critical security practices like avoiding client secrets in public clients.
Includes specific guidance on avoiding destructive 'full replace' API calls.
Offers a structured approach to troubleshooting common authentication and federation issues.
Aligns with industry-standard security patterns for token handling and API protection.

Usage examples

“How do I set up a user pool for a React app with hosted UI?”: The agent provides steps to create a user pool, configure a public app client, enable the hosted UI with authorization code grant and PKCE, and wire the Amplify client library.
“My API Gateway is returning 401 errors for valid tokens, what should I check?”: The agent guides you to verify the token type, check the issuer and audience configuration in the JWT authorizer, and ensure the correct token is being sent in the Authorization header.
“How do I allow my mobile app users to upload files directly to S3?”: The agent explains how to set up an identity pool that trusts your user pool, maps authenticated users to an IAM role with S3 permissions, and vends temporary credentials.
“How do I add Google login to my Cognito user pool?”: The agent outlines the process of registering Google as an IdP in the user pool, mapping attributes, and updating the app client to include the provider.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/aws/aws-auth/download
Unzip it into the cross-client skills folder of your project:
```
mkdir -p .agents/skills && unzip aws-auth.zip -d .agents/skills
```

Documentation by AWS

AWS Auth (Amazon Cognito)

Application-level user authentication and authorization with Amazon Cognito and the Amplify client auth libraries. Verify specific limits, quotas, and exact API shapes against official AWS documentation when precision matters; trust the docs over memory when they conflict.

Recommended: The AWS MCP server provides streamlined access to the AWS APIs used in this skill (Cognito user pool/app client/identity pool setup, API Gateway authorizers). If it is unavailable, the AWS CLI commands shown throughout work directly — the skill has no hard dependency on MCP.

When NOT to use: Amplify Gen2 backend code (defineAuth, amplify/auth.ts, npx ampx); IAM policy/role/trust-policy authoring, STS, or IAM Identity Center console SSO; API Gateway route/integration setup or Lambda function implementation (this skill covers only the Cognito/JWT authorizer configuration and the purpose of Cognito Lambda triggers).

User Pool vs Identity Pool — pick first

These are different services that are frequently confused. Most apps need a user pool; add an identity pool only if the client must call AWS services directly.

You need...	Use	Why
Sign-up / sign-in, user directory, issue JWTs	User pool	It authenticates users and is an OIDC IdP
The signed-in client to call S3/DynamoDB/etc. directly with AWS credentials	Identity pool	It exchanges a token for temporary AWS credentials via STS
Both (sign in, then hit AWS resources from the browser/app)	User pool → identity pool	Identity pool trusts the user pool as its IdP

If your app only calls your own backend/API, you do not need an identity pool — send the user pool token to your API. See identity-pools.md.

Critical Warnings

update-user-pool-client and set-identity-pool-roles are FULL REPLACE, not partial updates: Any field you omit is reset to its default — calling update-user-pool-client with only the fields you want to change silently wipes ExplicitAuthFlows, token validity, EnableTokenRevocation, refresh-token rotation, and read/write attributes; set-identity-pool-roles likewise replaces the whole roles + RoleMappings structure. Always read-modify-write: describe-user-pool-client (or get-identity-pool-roles) first, then re-send every existing field plus your change. In an agent context the wipe is invisible — the call succeeds and only breaks later when a user hits the missing flow. See managed-login-oauth.md and identity-pools.md.

Don't use the implicit grant for new apps: The implicit grant (response_type=token) is legacy and returns tokens in the URL fragment. Use the authorization code grant with PKCE (response_type=code + code_challenge) for SPAs and mobile — public clients, no client secret. See managed-login-oauth.md.

Don't store refresh tokens in localStorage for high-value apps: localStorage is readable by any injected script (XSS). The Amplify client library defaults to localStorage; switch to cookieStorage, keep refresh-token lifetime short, and enable refresh token rotation + token revocation on the app client. See tokens-and-sessions.md.

Access-token claim customization needs a paid feature plan: The pre token generation trigger customizes the ID token on the entry-level plan (V1), but customizing the access token (V2/V3) requires a paid feature plan — check the Cognito feature plans documentation for which plan currently includes this, as plan names and inclusions can change. Don't assume access-token claims work on the entry-level plan. See lambda-triggers.md.

App client secret + SPA = broken auth: A public client (browser/mobile) must have no client secret. If a secret is set, token calls fail unless a SECRET_HASH is sent, which a browser cannot protect. Generate a secret only for confidential (server-side) clients.

Don't bulk admin-confirm-sign-up UNCONFIRMED users: When users are stuck UNCONFIRMED, prefer resend-confirmation-code so each user re-verifies via confirm-sign-up and proves email ownership (the code likely expired or went to spam). admin-confirm-sign-up flips the status instantly but confirms the account without verifying the email — the attribute stays unverified, which is dangerous when email drives password reset or account linking. Reserve it for trusted/migrated accounts. See troubleshooting.md.

You want to...	Go to
Create a user pool, sign-up/sign-in, MFA, password policy, app clients	user-pools.md
Add hosted UI / managed login, OAuth flows, social or SAML login, callback URLs, custom domain (ACM in us-east-1)	managed-login-oauth.md
Handle ID/access/refresh tokens, rotation, revocation, session termination (global sign-out vs revoke vs disable)	tokens-and-sessions.md
Give the client temporary AWS credentials, guest access, role mapping	identity-pools.md
Protect an API Gateway API with Cognito tokens (and enforce custom claims in the backend)	api-authorization.md
Add Cognito login in front of an Application Load Balancer (ALB `authenticate-cognito`)	api-authorization.md
Machine-to-machine (client credentials) auth, resource servers, custom scopes	managed-login-oauth.md
Create user pool groups and add users to them (`cognito:groups`, `Precedence`)	user-pools.md
Customize claims, custom auth challenge flows, migrate users, validate sign-up	lambda-triggers.md
Add passkey / WebAuthn sign-in (`USER_AUTH` flow, `AllowedFirstAuthFactors`, WebAuthn enrollment)	passkeys.md
Configure threat protection — compromised-credentials block, adaptive auth (risk-based MFA), log delivery to CloudWatch	threat-protection.md
Something is broken (redirect, token, MFA, CORS, social login)	troubleshooting.md

Common Workflows

"Add sign-up and login to my React app" → Create a user pool + a public app client (no secret), enable the hosted UI / managed login with the authorization code grant with PKCE, wire the Amplify client library. See user-pools.md and managed-login-oauth.md.

"Add Google / social login" → Register the social IdP on the user pool, map attributes, add the provider to the app client and hosted UI. See managed-login-oauth.md.

"Only authenticated users should call my API" → HTTP API → JWT authorizer; REST API → Cognito user pools authorizer. See api-authorization.md.

"Let the browser upload to S3 after login" → User pool for sign-in, then an identity pool to vend scoped temporary credentials. See identity-pools.md.

Troubleshooting

Error/Symptom	Likely Cause	Quick Fix
`redirect_mismatch` / redirect to wrong URL after login	Callback URL not registered, or scheme/trailing-slash/case differs	Add the exact callback URL (incl. scheme and path) to the app client's Allowed callback URLs
Token calls fail with "unable to verify secret hash"	Client secret set on a public (SPA/mobile) client	Recreate the app client with no secret, or send `SECRET_HASH` from a confidential client
Users get 401 from API Gateway with a valid token	Wrong token type or audience/issuer mismatch	HTTP JWT authorizer: issuer `https://cognito-idp.{region}.amazonaws.com/{userPoolId}`, audience = app client id; send the token the authorizer expects
CORS errors calling the hosted UI / token endpoint	Browser calling `/oauth2/token` cross-origin, or missing CORS on your API	Do the code exchange with PKCE; don't proxy the token endpoint from the browser
Social login user "already exists" / attribute conflict	Same email across providers creates separate users	Enable attribute mapping + account linking; treat email as non-unique across IdPs

Full tables in troubleshooting.md.

Security Considerations

Public clients (SPA/mobile): no client secret, authorization code grant with PKCE, request least-privilege scopes.
Enable MFA (TOTP or SMS), a strong password policy, and advanced security / threat protection where available.
Short access-token lifetime; enable refresh token rotation and token revocation; prefer cookieStorage over localStorage.
Identity pools: scope the authenticated IAM role tightly; disable unauthenticated (guest) access unless required.
Validate JWTs against the user pool JWKS (iss, aud/client_id, token_use, exp) on every protected request. Use a maintained library such as aws-jwt-verify rather than hand-rolling verification.
Set security headers on the app's web pages: Content-Security-Policy (restrict script sources to mitigate token-stealing XSS), Strict-Transport-Security (HSTS), X-Frame-Options/frame-ancestors (clickjacking on login pages), and X-Content-Type-Options: nosniff.
Enable logging and monitoring: CloudTrail for Cognito API events (sign-up/sign-in/admin), user pool threat protection (adaptive auth + event logging), CloudWatch alarms on failed/throttled auth, and API Gateway access logging for authorizer decisions.
All Cognito and API endpoints are HTTPS/TLS only; enable encryption at rest with a customer-managed KMS key (and restricted key access) on CloudWatch Log groups, SNS topics used for MFA/notifications, and any identity-pool-fronted upload buckets.
If using SNS for MFA/notification delivery, enable server-side encryption (KMS) on the topic, and keep SMS/email message content limited to what the recipient needs — don't include more PII than the message requires.
References: Amazon Cognito security features (user pools), Amazon Cognito security (top-level, incl. identity pools), and IAM/STS best practices.

Where to Look When This Skill Is Silent

When you need depth beyond this skill — exact parameter shapes, current limits, edge behaviors — fall back to the authoritative AWS sources rather than guessing. Pointers age much slower than content, so this map stays useful without the skill having to grow.

API reference (exact params, defaults, errors): Cognito User Pools API and Cognito Identity API
Developer Guide (concepts, workflows): Amazon Cognito Developer Guide
Quotas, rate limits, session-cookie lifetime: Cognito quotas
Feature plans / tier gating: Cognito feature plans
Pricing: Amazon Cognito pricing
CLI reference: aws cognito-idp and aws cognito-identity

Not Covered By This Skill

Amplify Gen2 backend (defineAuth, amplify/auth.ts, npx ampx sandbox).
IAM policy/role/trust-policy authoring, STS, IAM Identity Center console SSO.
API Gateway route/integration setup and Lambda function implementation (this skill covers only the Cognito/JWT authorizer configuration and the purpose of Cognito Lambda triggers).

Files

ATTRIBUTION.mdAdded by AutoGineer881 B
LICENSELicence file added by AutoGineer9.9 KiB
NOTICELicence file added by AutoGineer67 B
SKILL.md13.5 KiB
references/api-authorization.md5.0 KiB
references/identity-pools.md5.8 KiB
references/lambda-triggers.md9.9 KiB
references/managed-login-oauth.md15.4 KiB
references/passkeys.md4.9 KiB
references/threat-protection.md5.9 KiB
references/tokens-and-sessions.md11.2 KiB
references/troubleshooting.md4.6 KiB
references/user-pools.md8.5 KiB

references/threat-protection.md

Threat Protection & Adaptive Authentication

Overview

Cognito's threat protection (formerly "advanced security features") detects and responds to suspicious sign-in activity: compromised (breached) passwords, risky patterns (new device, unusual IP), and risk-based adaptive MFA.

Feature-plan gate

Threat protection features require the Plus feature plan:

AdvancedSecurityMode = AUDIT | ENFORCED — Plus only.
Adaptive-auth risk configuration — Plus only.
Threat-protection log delivery (userAuthEvents event source) — Plus only.

Attempting these on a lower tier returns FeatureUnavailableInTierException. Set via update-user-pool --user-pool-tier PLUS.

`AdvancedSecurityMode` — three modes

Lives on UserPool.UserPoolAddOns.AdvancedSecurityMode (nested, not top-level):

Mode	Behavior
`OFF`	Threat protection disabled
`AUDIT`	Records risk assessments; takes NO action. Data-gathering mode
`ENFORCED`	Records AND applies your configured risk responses

Toggle via update-user-pool (NOT set-risk-configuration):

aws cognito-idp update-user-pool \
  --user-pool-id <pool-id> \
  --user-pool-add-ons AdvancedSecurityMode=ENFORCED \
  ... (re-send every other existing field — full-replace API)

Compromised-credentials protection

Detects passwords on known-breached lists. Configure via set-risk-configuration:

aws cognito-idp set-risk-configuration \
  --user-pool-id <pool-id> \
  --compromised-credentials-risk-configuration \
    'Actions={EventAction=BLOCK},EventFilter=[SIGN_IN,SIGN_UP,PASSWORD_CHANGE]'

EventAction: BLOCK (reject the auth attempt) or NO_ACTION (log only).
EventFilter: any subset of SIGN_IN | SIGN_UP | PASSWORD_CHANGE. Defaults to all three when omitted.
Omit --client-id for pool-wide config; include it to scope to one client.

Adaptive authentication (risk-based MFA)

Cognito classifies each sign-in as No Risk / Low / Medium / High. The API exposes three configurable action tiers (LowAction / MediumAction / HighAction) — No Risk proceeds without triggering any Action.

aws cognito-idp set-risk-configuration \
  --user-pool-id <pool-id> \
  --account-takeover-risk-configuration '
    NotifyConfiguration={
      SourceArn=arn:aws:ses:us-east-1:<account>:identity/[email protected],
      [email protected]
    },
    Actions={
      LowAction={EventAction=NO_ACTION,Notify=false},
      MediumAction={EventAction=MFA_IF_CONFIGURED,Notify=true},
      HighAction={EventAction=MFA_REQUIRED,Notify=true}
    }'

`EventAction` — four values per tier

Value	Behavior
`NO_ACTION`	Allow the sign-in
`MFA_IF_CONFIGURED`	Require MFA if the user has it set up; allow otherwise (optional MFA)
`MFA_REQUIRED`	Require MFA; block if user has no MFA method (required MFA)
`BLOCK`	Reject the sign-in outright

Do NOT collapse MFA_IF_CONFIGURED and MFA_REQUIRED — they behave differently. Typical: Low → NO_ACTION, Medium → MFA_IF_CONFIGURED, High → MFA_REQUIRED or BLOCK.

`NotifyConfiguration`

SourceArn is required and must be a verified SES identity ARN.
Optional: From, ReplyTo, and per-outcome message bodies (BlockEmail, MfaEmail, NoActionEmail, each with Subject/HtmlBody/TextBody).

Log delivery to CloudWatch

Route threat-protection events to CloudWatch/S3/Firehose via set-log-delivery-configuration:

aws cognito-idp set-log-delivery-configuration \
  --user-pool-id <pool-id> \
  --log-configurations '[
    {
      "EventSource": "userAuthEvents",
      "LogLevel": "INFO",
      "CloudWatchLogsConfiguration": {"LogGroupArn": "arn:aws:logs:<region>:<account>:log-group:<name>"}
    }
  ]'

Enum-pair rules (Cognito rejects mismatched pairs):

`EventSource`	`LogLevel`	Purpose	Tier
`userAuthEvents`	`INFO`	Threat-protection sign-in events	Plus
`userNotification`	`ERROR`	Message-delivery errors (SMS, email)	Lite+

Encrypt the target CloudWatch Logs log group with a customer-managed KMS key — threat-protection events contain user PII (IP addresses, user identifiers) and sign-in risk metadata. Either set the KMS key at log-group creation, or associate one after the fact:

aws logs associate-kms-key \
  --log-group-name /aws/cognito/<pool-id> \
  --kms-key-id arn:aws:kms:<region>:<account>:key/<key-id>

The KMS key policy must allow the logs.<region>.amazonaws.com service principal kms:Encrypt* / kms:Decrypt* / kms:GenerateDataKey* / kms:Describe* scoped to the log group ARN via kms:EncryptionContext:aws:logs:arn.

Inspect current state

aws cognito-idp describe-user-pool --user-pool-id <pool-id>          # AdvancedSecurityMode
aws cognito-idp describe-risk-configuration --user-pool-id <pool-id> # risk config
aws cognito-idp get-log-delivery-configuration --user-pool-id <pool-id>

Gotchas

UserPoolAddOns block may be absent if threat protection never enabled — inspect defensively: pool.get("UserPoolAddOns", {}).get("AdvancedSecurityMode").
Downgrading Plus → lower tier fails while AdvancedSecurityMode is AUDIT/ENFORCED. Set to OFF first, then change tier.
set-risk-configuration with only UserPoolId clears the config to defaults — always read-modify-write.

Authoritative sources

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Node.js

Security

No issues found by our static scan· No issues found

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Attribution and licence

Published by

AWS

Publisher

AWS (Official)

Source

aws/agent-toolkit-for-aws · skills/core-skills/aws-auth · commit 0a218f8

Licence

Apache License 2.0 (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
NOTICE (added by AutoGineer from NOTICE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-09

Also distributed in

aws/agent-toolkit-for-aws

AutoGineer is not affiliated with or endorsed by AWS or AWS.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download aws-auth.zip