How do I install the Cloudformation skill?

Run npx skillmds@latest add gabrielmoreira/cloudformation in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Cloudformation skill do?

Deploy AWS resources with CloudFormation templates. Create stacks, use nested stacks, and implement drift detection. Use when deploying AWS-native IaC. It is listed under DevOps & Infra on SkillMD.

Is Cloudformation safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Cloudformation?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Cloudformation free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Cloudformation?

gabrielmoreira (@gabrielmoreira) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Cloudformation by gabrielmoreira — Agent Skill

Name: Cloudformation
Rating: 4.2 (5 reviews)
Author: gabrielmoreira

CloudFormation

Deploy AWS infrastructure with native CloudFormation templates, change sets, nested stacks, and drift detection.

When to Use This Skill

Deploying AWS resources using AWS-native Infrastructure as Code
Creating repeatable, parameterized infrastructure templates
Managing multi-environment deployments (dev, staging, prod) with the same template
Implementing safe deployments with change sets and rollback protection
Detecting and remediating configuration drift
Organizing large infrastructure into nested stacks
Exporting/importing values between stacks

Prerequisites

AWS CLI v2 installed and configured
IAM permissions: cloudformation:*, plus permissions for all resources in the template
(Optional) cfn-lint installed for template validation (pip install cfn-lint)
S3 bucket for storing templates larger than 51,200 bytes

Template Structure

AWSTemplateFormatVersion: '2010-09-09'
Description: Production web application infrastructure

Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
      - Label: { default: "Environment" }
        Parameters: [Environment, InstanceType]
      - Label: { default: "Network" }
        Parameters: [VpcId, SubnetIds]

Parameters:
  Environment:
    Type: String
    AllowedValues: [dev, staging, prod]
    Default: dev

  InstanceType:
    Type: String
    Default: t3.micro
    AllowedValues: [t3.micro, t3.small, t3.medium, t3.large]

  VpcId:
    Type: AWS::EC2::VPC::Id
    Description: VPC to deploy into

  SubnetIds:
    Type: List<AWS::EC2::Subnet::Id>
    Description: Subnets for the application

Conditions:
  IsProd: !Equals [!Ref Environment, prod]
  CreateReadReplica: !Equals [!Ref Environment, prod]

Mappings:
  RegionAMI:
    us-east-1:
      AL2023: ami-0abcdef1234567890
    us-west-2:
      AL2023: ami-0fedcba9876543210

Resources:
  SecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: !Sub '${Environment}-web-sg'
      VpcId: !Ref VpcId
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 443
          ToPort: 443
          CidrIp: 0.0.0.0/0
      Tags:
        - Key: Name
          Value: !Sub '${Environment}-web-sg'

  LaunchTemplate:
    Type: AWS::EC2::LaunchTemplate
    Properties:
      LaunchTemplateName: !Sub '${Environment}-web'
      LaunchTemplateData:
        ImageId: !FindInMap [RegionAMI, !Ref 'AWS::Region', AL2023]
        InstanceType: !If [IsProd, t3.large, !Ref InstanceType]
        MetadataOptions:
          HttpTokens: required
        SecurityGroupIds:
          - !Ref SecurityGroup

  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      AutoScalingGroupName: !Sub '${Environment}-web-asg'
      LaunchTemplate:
        LaunchTemplateId: !Ref LaunchTemplate
        Version: !GetAtt LaunchTemplate.LatestVersionNumber
      MinSize: !If [IsProd, 2, 1]
      MaxSize: !If [IsProd, 10, 3]
      DesiredCapacity: !If [IsProd, 4, 1]
      VPCZoneIdentifier: !Ref SubnetIds
      TargetGroupARNs:
        - !Ref TargetGroup
      HealthCheckType: ELB
      HealthCheckGracePeriod: 300
      Tags:
        - Key: Name
          Value: !Sub '${Environment}-web'
          PropagateAtLaunch: true
    UpdatePolicy:
      AutoScalingRollingUpdate:
        MinInstancesInService: !If [IsProd, 2, 0]
        MaxBatchSize: 1
        PauseTime: PT5M
        WaitOnResourceSignals: true
        SuspendProcesses:
          - HealthCheck
          - ReplaceUnhealthy
          - AZRebalance
          - AlarmNotification
          - ScheduledActions

  TargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      Name: !Sub '${Environment}-web-tg'
      Port: 8080
      Protocol: HTTP
      VpcId: !Ref VpcId
      TargetType: instance
      HealthCheckPath: /health
      HealthCheckIntervalSeconds: 30
      HealthyThresholdCount: 2
      UnhealthyThresholdCount: 3

Outputs:
  SecurityGroupId:
    Description: Web security group ID
    Value: !Ref SecurityGroup
    Export:
      Name: !Sub '${Environment}-WebSecurityGroup'

  AutoScalingGroupName:
    Description: ASG name
    Value: !Ref AutoScalingGroup
    Export:
      Name: !Sub '${Environment}-WebASG'

Stack Operations

# Validate a template
aws cloudformation validate-template --template-body file://template.yaml

# Lint with cfn-lint (catches more issues)
cfn-lint template.yaml

# Create a stack
aws cloudformation create-stack \
  --stack-name production-web \
  --template-body file://template.yaml \
  --parameters \
    ParameterKey=Environment,ParameterValue=prod \
    ParameterKey=VpcId,ParameterValue=vpc-abc123 \
    ParameterKey=SubnetIds,ParameterValue="subnet-aaa\\,subnet-bbb" \
  --capabilities CAPABILITY_IAM CAPABILITY_NAMED_IAM \
  --tags Key=Environment,Value=production Key=Team,Value=platform \
  --enable-termination-protection \
  --on-failure ROLLBACK

# Wait for stack creation
aws cloudformation wait stack-create-complete --stack-name production-web

# Describe stack status and outputs
aws cloudformation describe-stacks \
  --stack-name production-web \
  --query "Stacks[0].{Status:StackStatus,Outputs:Outputs}" \
  --output table

# List stack resources
aws cloudformation list-stack-resources --stack-name production-web \
  --query "StackResourceSummaries[].{Logical:LogicalResourceId,Physical:PhysicalResourceId,Type:ResourceType,Status:ResourceStatus}" \
  --output table

# Delete a stack
aws cloudformation delete-stack --stack-name dev-web
aws cloudformation wait stack-delete-complete --stack-name dev-web

Change Sets (Safe Updates)

# Create a change set to preview changes before applying
aws cloudformation create-change-set \
  --stack-name production-web \
  --change-set-name update-instance-type \
  --template-body file://template.yaml \
  --parameters \
    ParameterKey=Environment,ParameterValue=prod \
    ParameterKey=InstanceType,ParameterValue=t3.large \
    ParameterKey=VpcId,UsePreviousValue=true \
    ParameterKey=SubnetIds,UsePreviousValue=true \
  --capabilities CAPABILITY_IAM

# Describe the change set to review planned changes
aws cloudformation describe-change-set \
  --stack-name production-web \
  --change-set-name update-instance-type \
  --query "Changes[].{Action:ResourceChange.Action,Resource:ResourceChange.LogicalResourceId,Type:ResourceChange.ResourceType,Replacement:ResourceChange.Replacement}" \
  --output table

# Execute the change set (apply changes)
aws cloudformation execute-change-set \
  --stack-name production-web \
  --change-set-name update-instance-type

# Wait for update
aws cloudformation wait stack-update-complete --stack-name production-web

# Delete a change set without applying
aws cloudformation delete-change-set \
  --stack-name production-web \
  --change-set-name update-instance-type

Drift Detection

# Start drift detection
DRIFT_ID=$(aws cloudformation detect-stack-drift \
  --stack-name production-web \
  --query 'StackDriftDetectionId' --output text)

# Check drift detection status
aws cloudformation describe-stack-drift-detection-status \
  --stack-drift-detection-id $DRIFT_ID

# View drifted resources
aws cloudformation describe-stack-resource-drifts \
  --stack-name production-web \
  --stack-resource-drift-status-filters MODIFIED DELETED \
  --query "StackResourceDrifts[].{Resource:LogicalResourceId,Status:StackResourceDriftStatus,Differences:PropertyDifferences}" \
  --output table

# Detect drift on a specific resource
aws cloudformation detect-stack-resource-drift \
  --stack-name production-web \
  --logical-resource-id SecurityGroup

Nested Stacks

Parent template:

AWSTemplateFormatVersion: '2010-09-09'
Description: Parent stack - full application

Parameters:
  Environment:
    Type: String
    AllowedValues: [dev, staging, prod]

Resources:
  NetworkStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/my-cfn-templates/network.yaml
      Parameters:
        Environment: !Ref Environment
        VpcCidr: "10.0.0.0/16"
      Tags:
        - Key: Environment
          Value: !Ref Environment

  DatabaseStack:
    Type: AWS::CloudFormation::Stack
    DependsOn: NetworkStack
    Properties:
      TemplateURL: https://s3.amazonaws.com/my-cfn-templates/database.yaml
      Parameters:
        Environment: !Ref Environment
        VpcId: !GetAtt NetworkStack.Outputs.VpcId
        SubnetIds: !GetAtt NetworkStack.Outputs.PrivateSubnetIds

  AppStack:
    Type: AWS::CloudFormation::Stack
    DependsOn: [NetworkStack, DatabaseStack]
    Properties:
      TemplateURL: https://s3.amazonaws.com/my-cfn-templates/app.yaml
      Parameters:
        Environment: !Ref Environment
        VpcId: !GetAtt NetworkStack.Outputs.VpcId
        SubnetIds: !GetAtt NetworkStack.Outputs.PrivateSubnetIds
        DbEndpoint: !GetAtt DatabaseStack.Outputs.Endpoint

Outputs:
  VpcId:
    Value: !GetAtt NetworkStack.Outputs.VpcId
  AppUrl:
    Value: !GetAtt AppStack.Outputs.LoadBalancerDNS

# Package nested templates (uploads local references to S3)
aws cloudformation package \
  --template-file parent.yaml \
  --s3-bucket my-cfn-templates \
  --output-template-file packaged.yaml

# Deploy the packaged template
aws cloudformation deploy \
  --template-file packaged.yaml \
  --stack-name production-app \
  --parameter-overrides Environment=prod \
  --capabilities CAPABILITY_IAM CAPABILITY_AUTO_EXPAND \
  --tags Environment=production

Intrinsic Functions Reference

# Ref - reference a parameter or resource
SecurityGroupId: !Ref SecurityGroup

# GetAtt - get an attribute of a resource
SecurityGroupArn: !GetAtt SecurityGroup.GroupId

# Sub - string substitution
BucketName: !Sub '${Environment}-${AWS::AccountId}-data'

# Join - concatenate strings
PolicyArn: !Join ['', ['arn:aws:iam::', !Ref 'AWS::AccountId', ':policy/MyPolicy']]

# Select - pick from a list
FirstSubnet: !Select [0, !Ref SubnetIds]

# Split - split a string
FirstPart: !Select [0, !Split ['-', !Ref 'AWS::StackName']]

# If - conditional value
InstanceSize: !If [IsProd, t3.large, t3.micro]

# Equals - condition definition
Conditions:
  IsProd: !Equals [!Ref Environment, prod]

# ImportValue - cross-stack reference
VpcId: !ImportValue production-VpcId

# Cidr - generate CIDR blocks
Subnets: !Cidr [!GetAtt VPC.CidrBlock, 6, 8]

# GetAZs - list availability zones
AZ: !Select [0, !GetAZs '']

Stack Policy (Prevent Accidental Replacements)

# Apply a stack policy that prevents replacement of the database
aws cloudformation set-stack-policy \
  --stack-name production-web \
  --stack-policy-body '{
    "Statement": [
      {
        "Effect": "Allow",
        "Action": "Update:*",
        "Principal": "*",
        "Resource": "*"
      },
      {
        "Effect": "Deny",
        "Action": "Update:Replace",
        "Principal": "*",
        "Resource": "LogicalResourceId/Database"
      },
      {
        "Effect": "Deny",
        "Action": "Update:Delete",
        "Principal": "*",
        "Resource": "LogicalResourceId/Database"
      }
    ]
  }'

Stack Events and Debugging

# View stack events (most recent first)
aws cloudformation describe-stack-events \
  --stack-name production-web \
  --query "StackEvents[?ResourceStatus=='CREATE_FAILED' || ResourceStatus=='UPDATE_FAILED'].{Time:Timestamp,Resource:LogicalResourceId,Status:ResourceStatus,Reason:ResourceStatusReason}" \
  --output table

# Continue a rollback that is stuck
aws cloudformation continue-update-rollback \
  --stack-name production-web \
  --resources-to-skip SecurityGroup

# Cancel an in-progress update
aws cloudformation cancel-update-stack --stack-name production-web

# Get template from an existing stack
aws cloudformation get-template \
  --stack-name production-web \
  --template-stage Processed \
  --query TemplateBody \
  --output text > current-template.yaml

Troubleshooting

Problem	Cause	Fix
CREATE_FAILED on IAM resource	Missing CAPABILITY_IAM	Add `--capabilities CAPABILITY_IAM CAPABILITY_NAMED_IAM`
Stack stuck in UPDATE_ROLLBACK_FAILED	Resource cannot be rolled back	Use `continue-update-rollback` with `--resources-to-skip`
Nested stack fails	Template URL wrong or S3 access denied	Use `aws cloudformation package` to upload; check bucket policy
Circular dependency error	Two resources reference each other	Break the cycle with a third resource or use `DependsOn`
Drift detected	Manual changes made outside CloudFormation	Re-apply the template or update template to match current state
Change set shows no changes	Template and parameters identical	Verify the diff; check if the change is parameter-only
Template validation error	YAML syntax or invalid resource property	Run `cfn-lint`; check property names against docs
Export name already exists	Another stack uses the same export name	Use unique export names with `!Sub '${AWS::StackName}-Name'`
Delete fails - resource in use	Dependent resource outside the stack	Remove the dependency first; check for SG references

Related Skills

terraform-aws - Alternative IaC with Terraform
aws-iam - IAM resources in templates
aws-vpc - Network infrastructure templates
aws-ec2 - Compute resources in templates
aws-s3 - Storage resources in templates

Cloudformation

File contents

CloudFormation

When to Use This Skill

Prerequisites

Template Structure

Stack Operations

Change Sets (Safe Updates)

Drift Detection

Nested Stacks

Intrinsic Functions Reference

Stack Policy (Prevent Accidental Replacements)

Stack Events and Debugging

Troubleshooting

Related Skills

Frequently asked questions

Cloudformation

File contents

CloudFormation

When to Use This Skill

Prerequisites

Template Structure

Stack Operations

Change Sets (Safe Updates)

Drift Detection

Nested Stacks

Intrinsic Functions Reference

Stack Policy (Prevent Accidental Replacements)

Stack Events and Debugging

Troubleshooting

Related Skills

Related skills

Frequently asked questions

How do I install the Cloudformation skill?

What does the Cloudformation skill do?

Is Cloudformation safe to use?

Which AI agents work with Cloudformation?

Is Cloudformation free to use?

Who published Cloudformation?