AWS Cloudformation S3

What it does

When your agent uses it

• Creating S3 buckets
• Lifecycle rules
• Implementing template structure with Parameters
• Cross-stack references

Example prompts

• “Use the aws-cloudformation-s3 skill to provide AWS CloudFormation patterns for Amazon S3. An agent skill from giuseppe-trisciuoglio/developer-kit”
• “/aws-cloudformation-s3”

Requirements

• Pre-approved tools (allowed-tools): Read, Write, Bash

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

1. 1Define Bucket Resources: Create AWS::S3::Bucket with versioning, encryption, PublicAccessBlock
2. 2Configure Bucket Policy: Set up IAM policies for access control
3. 3Set Up Lifecycle Rules: Define transitions and expiration policies
4. 4Configure CORS: Allow cross-origin requests if needed
5. 5Add Outputs: Export bucket names/ARNs for cross-stack references

What it can do on your machine

Read from SKILL.md and the folder at commit fe73fb3. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Write
  • Bash

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • aws

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md. Its commands use aws, which can reach the network depending on how they are called.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

AWS Cloudformation S3 loads about 1.8k tokens when it runs, and up to ~14k if it reads all its reference files. Until then it costs about 64 tokens; SKILL.md has 485 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~64

When it runs · the whole SKILL.md, loaded when a task matches

~1.8k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~14k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NotePre-approves every shell command (allowed-tools: Bash)SKILL.md

  allowed-tools: Read, Write, Bash

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from giuseppe-trisciuoglio/developer-kit at commit fe73fb3, republished under its MIT licence (© giuseppe-trisciuoglio). 485 words, ~1,816 tokens.

name

aws-cloudformation-s3

description

Provides AWS CloudFormation patterns for Amazon S3. Use when creating S3 buckets, policies, versioning, lifecycle rules, and implementing template structure with Parameters, Outputs, Mappings, Conditions, and cross-stack references.

allowed-tools

Read, Write, Bash

aws cloudformation validate-template --template-body file://template.yaml

aws cloudformation deploy \
  --template-file template.yaml \
  --stack-name my-s3-stack \
  --capabilities CAPABILITY_IAM

aws cloudformation describe-stack-events --stack-name my-s3-stack

Resources:
  DataBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: my-data-bucket

DataBucket:
  Type: AWS::S3::Bucket
  Properties:
    BucketName: !Sub "${AWS::StackName}-data"
    VersioningConfiguration:
      Status: Enabled
    BucketEncryption:
      ServerSideEncryptionConfiguration:
        - ServerSideEncryptionByDefault:
            SSEAlgorithm: AES256
    PublicAccessBlockConfiguration:
      BlockPublicAcls: true
      BlockPublicPolicy: true

DataBucket:
  Type: AWS::S3::Bucket
  Properties:
    LifecycleConfiguration:
      Rules:
        - Id: ArchiveOldData
          Status: Enabled
          Transitions:
            - StorageClass: GLACIER
              TransitionInDays: 365

BucketPolicy:
  Type: AWS::S3::BucketPolicy
  Properties:
    Bucket: !Ref DataBucket
    PolicyDocument:
      Statement:
        - Effect: Allow
          Principal:
            AWS: !Ref RoleArn
          Action:
            - s3:GetObject
          Resource: !Sub "${DataBucket.Arn}/*"

AWSTemplateFormatVersion: 2010-09-09
Description: Template description

Mappings: {}       # Static configuration tables
Metadata: {}       # Additional information
Parameters: {}     # Input values
Conditions: {}     # Conditional creation
Transform: {}      # Macro processing
Resources: {}      # AWS resources (REQUIRED)
Outputs: {}        # Return values

Parameters:
  BucketName:
    Type: String
    Description: S3 bucket name
    Default: my-bucket
    MinLength: 3
    MaxLength: 63
    AllowedPattern: '^[a-z0-9-]+$'

Conditions:
  IsProduction: !Equals [!Ref Environment, prod]
  ShouldEnableVersioning: !Equals [!Ref EnableVersioning, 'true']

Resources:
  DataBucket:
    Type: AWS::S3::Bucket
    Properties:
      VersioningConfiguration:
        Status: !If [ShouldEnableVersioning, Enabled, Suspended]

Outputs:
  BucketName:
    Description: Name of the S3 bucket
    Value: !Ref DataBucket
    Export:
      Name: !Sub '${AWS::StackName}-BucketName'

© giuseppe-trisciuoglio, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in plugins/developer-kit-aws/skills/aws-cloudformation/aws-cloudformation-s3 of giuseppe-trisciuoglio/developer-kit.

• SKILL.md
• references/advanced-configuration.md
• references/complete-examples.md
• references/examples.md
• references/reference.md

Open the folder on GitHubat commit fe73fb3