mcpbeat

Cognito

itsmostafa/cognito

AWS Cognito user authentication and authorization service. Use when setting up user pools, configuring identity pools, implementing OAuth flows, managing user attributes, or integrating with social identity providers.

5k tokens
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the whole folder, loaded on every use
2
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instructions only
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copies elsewhere
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on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/itsmostafa/aws-agent-skills --skill cognito

The instruction itself

29 sections, as written by the author

AWS Cognito

Amazon Cognito provides authentication, authorization, and user management for web and mobile applications. Users can sign in directly or through federated identity providers.

Table of Contents

  • Core Concepts
  • Common Patterns
  • CLI Reference
  • Best Practices
  • Troubleshooting
  • References

Core Concepts

User Pools

User directory for sign-up and sign-in. Provides:

  • User registration and authentication
  • OAuth 2.0 / OpenID Connect tokens
  • MFA and password policies
  • Customizable UI and flows

Identity Pools (Federated Identities)

Provide temporary AWS credentials to access AWS services. Users can be:

  • Cognito User Pool users
  • Social identity (Google, Facebook, Apple)
  • SAML/OIDC enterprise identity
  • Anonymous guests

Tokens

| Token | Purpose | Lifetime |

|-------|---------|----------|

| ID Token | User identity claims | 1 hour |

| Access Token | API authorization | 1 hour |

| Refresh Token | Get new ID/Access tokens | 30 days (configurable) |

Common Patterns

Create User Pool

AWS CLI:

aws cognito-idp create-user-pool \
  --pool-name my-app-users \
  --policies '{
    "PasswordPolicy": {
      "MinimumLength": 12,
      "RequireUppercase": true,
      "RequireLowercase": true,
      "RequireNumbers": true,
      "RequireSymbols": true
    }
  }' \
  --auto-verified-attributes email \
  --username-attributes email \
  --mfa-configuration OPTIONAL \
  --user-attribute-update-settings '{
    "AttributesRequireVerificationBeforeUpdate": ["email"]
  }'

Create App Client

aws cognito-idp create-user-pool-client \
  --user-pool-id us-east-1_abc123 \
  --client-name my-web-app \
  --generate-secret \
  --explicit-auth-flows ALLOW_USER_SRP_AUTH ALLOW_REFRESH_TOKEN_AUTH \
  --supported-identity-providers COGNITO \
  --callback-urls https://myapp.com/callback \
  --logout-urls https://myapp.com/logout \
  --allowed-o-auth-flows code \
  --allowed-o-auth-scopes openid email profile \
  --allowed-o-auth-flows-user-pool-client \
  --access-token-validity 60 \
  --id-token-validity 60 \
  --refresh-token-validity 30 \
  --token-validity-units '{
    "AccessToken": "minutes",
    "IdToken": "minutes",
    "RefreshToken": "days"
  }'

Sign Up User

import boto3
import hmac
import hashlib
import base64

cognito = boto3.client('cognito-idp')

def get_secret_hash(username, client_id, client_secret):
    message = username + client_id
    dig = hmac.new(
        client_secret.encode('utf-8'),
        message.encode('utf-8'),
        digestmod=hashlib.sha256
    ).digest()
    return base64.b64encode(dig).decode()

response = cognito.sign_up(
    ClientId='client-id',
    SecretHash=get_secret_hash('[email protected]', 'client-id', 'client-secret'),
    Username='[email protected]',
    Password='SecurePassword123!',
    UserAttributes=[
        {'Name': 'email', 'Value': '[email protected]'},
        {'Name': 'name', 'Value': 'John Doe'}
    ]
)

Confirm Sign Up

cognito.confirm_sign_up(
    ClientId='client-id',
    SecretHash=get_secret_hash('[email protected]', 'client-id', 'client-secret'),
    Username='[email protected]',
    ConfirmationCode='123456'
)

Authenticate User

response = cognito.initiate_auth(
    ClientId='client-id',
    AuthFlow='USER_SRP_AUTH',
    AuthParameters={
        'USERNAME': '[email protected]',
        'SECRET_HASH': get_secret_hash('[email protected]', 'client-id', 'client-secret'),
        'SRP_A': srp_a  # From SRP library
    }
)

# For simple password auth (not recommended for production)
response = cognito.admin_initiate_auth(
    UserPoolId='us-east-1_abc123',
    ClientId='client-id',
    AuthFlow='ADMIN_USER_PASSWORD_AUTH',
    AuthParameters={
        'USERNAME': '[email protected]',
        'PASSWORD': 'password',
        'SECRET_HASH': get_secret_hash('[email protected]', 'client-id', 'client-secret')
    }
)

tokens = response['AuthenticationResult']
id_token = tokens['IdToken']
access_token = tokens['AccessToken']
refresh_token = tokens['RefreshToken']

Refresh Tokens

response = cognito.initiate_auth(
    ClientId='client-id',
    AuthFlow='REFRESH_TOKEN_AUTH',
    AuthParameters={
        'REFRESH_TOKEN': refresh_token,
        'SECRET_HASH': get_secret_hash('[email protected]', 'client-id', 'client-secret')
    }
)

Create Identity Pool

aws cognito-identity create-identity-pool \
  --identity-pool-name my-app-identities \
  --allow-unauthenticated-identities \
  --cognito-identity-providers \
    ProviderName=cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123,\
ClientId=client-id,\
ServerSideTokenCheck=true

Get AWS Credentials

import boto3

cognito_identity = boto3.client('cognito-identity')

# Get identity ID
response = cognito_identity.get_id(
    IdentityPoolId='us-east-1:12345678-1234-1234-1234-123456789012',
    Logins={
        'cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123': id_token
    }
)
identity_id = response['IdentityId']

# Get credentials
response = cognito_identity.get_credentials_for_identity(
    IdentityId=identity_id,
    Logins={
        'cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123': id_token
    }
)

credentials = response['Credentials']
# Use credentials['AccessKeyId'], credentials['SecretKey'], credentials['SessionToken']

CLI Reference

User Pool

| Command | Description |

|---------|-------------|

| aws cognito-idp create-user-pool | Create user pool |

| aws cognito-idp describe-user-pool | Get pool details |

| aws cognito-idp update-user-pool | Update pool settings |

| aws cognito-idp delete-user-pool | Delete pool |

| aws cognito-idp list-user-pools | List pools |

Users

| Command | Description |

|---------|-------------|

| aws cognito-idp admin-create-user | Create user (admin) |

| aws cognito-idp admin-delete-user | Delete user |

| aws cognito-idp admin-get-user | Get user details |

| aws cognito-idp list-users | List users |

| aws cognito-idp admin-set-user-password | Set password |

| aws cognito-idp admin-disable-user | Disable user |

Authentication

| Command | Description |

|---------|-------------|

| aws cognito-idp initiate-auth | Start authentication |

| aws cognito-idp respond-to-auth-challenge | Respond to MFA |

| aws cognito-idp admin-initiate-auth | Admin authentication |

Best Practices

Security

  • Enable MFA for all users (at least optional)
  • Use strong password policies
  • Enable advanced security features (adaptive auth)
  • Verify email/phone before allowing sign-in
  • Use short token lifetimes for sensitive apps
  • Never expose client secrets in frontend code

User Experience

  • Use hosted UI for quick implementation
  • Customize UI with CSS
  • Implement proper error handling
  • Provide clear password requirements

Architecture

  • Use identity pools for AWS resource access
  • Use access tokens for API Gateway
  • Store refresh tokens securely
  • Implement token refresh before expiry

Troubleshooting

User Cannot Sign In

Causes:

  • User not confirmed
  • Password incorrect
  • User disabled
  • Account locked (too many attempts)

Debug:

aws cognito-idp admin-get-user \
  --user-pool-id us-east-1_abc123 \
  --username [email protected]

Token Validation Failed

Causes:

  • Token expired
  • Wrong user pool/client ID
  • Token signature invalid

Validate JWT:

import jwt
import requests

# Get JWKS
jwks_url = f'https://cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123/.well-known/jwks.json'
jwks = requests.get(jwks_url).json()

# Decode and verify (use python-jose or similar)
from jose import jwt

claims = jwt.decode(
    token,
    jwks,
    algorithms=['RS256'],
    audience='client-id',
    issuer='https://cognito-idp.us-east-1.amazonaws.com/us-east-1_abc123'
)

Hosted UI Not Working

Check:

  • Callback URLs configured correctly
  • Domain configured for user pool
  • OAuth settings enabled
# Check domain
aws cognito-idp describe-user-pool \
  --user-pool-id us-east-1_abc123 \
  --query 'UserPool.Domain'

Rate Limiting

Symptom: TooManyRequestsException

Solutions:

  • Implement exponential backoff
  • Request quota increase
  • Cache tokens appropriately

References

How to use it

Copy the folder

Take itsmostafa/cognito from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.