cloudformation

cloudformation is a skill for Claude Code, Codex from itsmostafa/aws-agent-skills. It costs 34 tokens per session (2,327 once invoked), scanned A, original, MIT.

A guide to AWS CloudFormation, a way to describe cloud infrastructure in JSON or YAML files and manage it as a group called a stack. The files can define resources, inputs, conditions, and returned values.

In plain words
What is it for?
Use it to write infrastructure templates, deploy and update stacks, manage nested stacks, check for configuration drift, and deploy the same setup across AWS accounts or regions.
Why use it?
It lets you keep infrastructure in version control and recreate it consistently across environments. Change sets show proposed updates before they are applied, helping reduce accidental changes.

Skill for Claude CodeCodex

Part of the aws-agent-skills plugin — 18 skills shipped together

About the project

AWS Agent Skills is a collection of local instructions that help coding agents reason about AWS cloud services and engineering tasks. It supports agents working with areas such as identity, compute, storage, serverless, databases, networking, and security. The catalogue contains 18 service-focused skills and one plugin for using these capabilities with coding agents.

itsmostafa/aws-agent-skills · 1,150 stars · on GitHub

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/itsmostafa/aws-agent-skills/cloudformation
Any agent
npx skills add itsmostafa/aws-agent-skills --skill cloudformation
Clone the repo
git clone --depth 1 https://github.com/itsmostafa/aws-agent-skills

Made for: Claude Code, Codex.

Or install aws-agent-skills, the plugin that ships this one along with the rest of its 18 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for cloudformation

README.md
[![agentmods](https://agentmods.dev/badge/skills/itsmostafa/aws-agent-skills/cloudformation.svg)](https://agentmods.dev/skills/itsmostafa/aws-agent-skills/cloudformation)
Your own site
<a href="https://agentmods.dev/skills/itsmostafa/aws-agent-skills/cloudformation"><img src="https://agentmods.dev/badge/skills/itsmostafa/aws-agent-skills/cloudformation.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,327 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00034 $0.02327
Opus 5 $0.00017 $0.01163
Sonnet 5 $0.00007 $0.00465
Haiku 4.5 $0.00003 $0.00233

Measured 6d ago against content hash 31654958084e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

cloudformation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/cloudformation/SKILL.md · 386 lines

How it starts

The opening of the file, as written. The whole thing — 386 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AWS CloudFormation

AWS CloudFormation provisions and manages AWS resources using templates. Define infrastructure as code, version control it, and deploy consistently across environments.

Table of Contents

Core Concepts

Templates

JSON or YAML files defining AWS resources. Key sections:

  • Parameters: Input values
  • Mappings: Static lookup tables
  • Conditions: Conditional resource creation
  • Resources: AWS resources (required)
  • Outputs: Return values

Stacks

Collection of resources managed as a single unit. Created from templates.

Change Sets

Preview changes before executing updates.

Stack Sets

Deploy stacks across multiple accounts and regions.

Common Patterns

Basic Template Structure

AWSTemplateFormatVersion: '2010-09-09'
Description: My infrastructure template

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

Mappings:
  EnvironmentConfig:
    dev:
      InstanceType: t3.micro
    prod:
      InstanceType: t3.large

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

Resources:
  MyBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Sub 'my-app-${Environment}-${AWS::AccountId}'
      VersioningConfiguration:
        Status: !If [IsProd, Enabled, Suspended]

Outputs:
  BucketName:
    Description: S3 bucket name
    Value: !Ref MyBucket
    Export:
      Name: !Sub '${AWS::StackName}-BucketName'

Deploy a Stack

AWS CLI:

# Create stack
aws cloudformation create-stack \
  --stack-name my-stack \
  --template-body file://template.yaml \
  --parameters ParameterKey=Environment,ParameterValue=prod \
  --capabilities CAPABILITY_IAM

# Wait for completion
aws cloudformation wait stack-create-complete --stack-name my-stack

# Update stack
aws cloudformation update-stack \
  --stack-name my-stack \
  --template-body file://template.yaml \
  --parameters ParameterKey=Environment,ParameterValue=prod

# Delete stack
aws cloudformation delete-stack --stack-name my-stack

Read the full file on GitHub · 386 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 386 lines · 34 tokens per session scan A 31654958084e

Subscribe to this mod's changes

cloudformation is a skill published in the GitHub repository itsmostafa/aws-agent-skills (1,150 stars, last pushed 5d ago), licensed MIT. It adds 34 tokens to every session and 2,327 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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