Cloudformation
CloudFormation template patterns, stack CLI commands, drift and rollback troubleshooting
Test report
- Verdict
- Tested · Works
- Score
- Tested
- Jul 21, 2026
- Environment
- Claude Code 2.x (agent harness)
- Upstream re-checked
- Aug 10, 2026 · 4b8c66c
Installed into a throwaway HOME (mktemp -d) and confirmed SKILL.md + template-patterns.md land at ~/.claude/skills/cloudformation/; frontmatter parsed via PyYAML with name+description present, both files returned HTTP 200 on raw fetch, and grep for curl-pipe-sh, base64, eval, wget, hardcoded /Users paths and injection phrasing found nothing. Task: "CloudFormation template for an image-upload pipeline (S3 bucket -> Lambda -> DynamoDB metadata), deployable to dev and prod" — wrote baseline.yaml (94 lines) from general knowledge, then skill.yaml (155 lines) following the body; a YAML parse of both showed baseline had 0 Mappings, 0 Conditions, 0 exported outputs, 0 output Descriptions, no PointInTimeRecovery, no ${AWS::StackName} naming (raw BucketName param instead), while the skill version had EnvironmentConfig mappings driving MemorySize/log retention via !FindInMap, an IsProd condition gating versioning and DeletionPolicy: Retain on 2 resources, 3/3 outputs with Description + Export, PITR enabled, a PK/SK+GSI1 table, a log group with retention, and SourceAccount added to the Lambda permission. Trigger phrasings judged: SHOULD fire — "Write a CloudFormation template for an S3 bucket that triggers a Lambda on upload", "My CloudFormation stack is stuck in DELETE_FAILED, how do I get it unstuck?", "How do I detect drift on the prod stack and see which resources changed?"; SHOULD NOT — "Write a Terraform module for an S3 bucket with versioning", "My Lambda times out on large payloads, help me debug the handler" — 5/5 correct. Docs docked because SKILL.md never references its own template-patterns.md companion (so half the shipped content never loads), and the repo README's Codex install example points at an "rlhf" skill that does not exist in this repo; cfn-lint and the AWS CLI are absent here so neither template was validated against the real service.
Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works
- Installs cleanly 5/5
- Triggers reliably 5/5
- Output vs. baseline 6/10
- Docs & honesty 4/5
What Cloudformation does
A reference skill for AWS CloudFormation that supplies template patterns (parameters, mappings, conditions, exported outputs, nested stacks, custom resources), a stack and change-set CLI command table, and troubleshooting recipes for CREATE_FAILED, DELETE_FAILED, drift detection, and stuck rollbacks. It triggers when you write or review CloudFormation templates, deploy or update stacks, or debug a failing stack. Output is knowledge only; running the commands still needs the AWS CLI and credentials.
How to install Cloudformation
git clone --depth 1 https://github.com/itsmostafa/aws-agent-skills.git /tmp/cloudformation-src
mkdir -p ~/.claude/skills
cp -R /tmp/cloudformation-src/skills/cloudformation ~/.claude/skills/cloudformation
# Verified in a clean HOME: places SKILL.md + template-patterns.md at ~/.claude/skills/cloudformation/
# No dependencies to install. Actually deploying stacks requires the AWS CLI and configured credentials.
# Alternative (installs all 18 AWS skills as a plugin, from Claude Code):
# /plugin marketplace add itsmostafa/aws-agent-skills
# /plugin install aws-agent-skills
# Note: template-patterns.md is never linked from SKILL.md, so read it explicitly if you want
# intrinsic-function, nested-stack, custom-resource, stack-policy, or DeletionPolicy detail.
Skills live in ~/.claude/skills/ (global) or .claude/skills/
(per-project). Restart Claude Code after installing.
Commands — how to trigger Cloudformation
-
/cloudformationCloudFormation template patterns, stack CLI commands, drift and rollback troubleshooting
It also activates on plain-language prompts like these:
-
Write a CloudFormation template for this stack -
Fix the drift detected in our CloudFormation stack -
Organize this infra using nested stacks
Frequently asked questions
- Is the Cloudformation skill free?
- Yes. The skill itself is free from itsmostafa/aws-agent-skills. SkillProof publishes the install command and an independent test verdict at no cost.
- Does Cloudformation work with Claude Code?
- We tested it with Claude Code 2.x (agent harness) on Jul 21, 2026. Verdict: Tested · Works. Installed into a throwaway HOME (mktemp -d) and confirmed SKILL.md + template-patterns.md land at ~/.claude/skills/cloudformation/; frontmatter parsed via PyYAML with name+description present, both files returned HTTP 200 on raw fetch, and grep for curl-pipe-sh, base64, eval, wget, hardcoded /Users paths and injection phrasing found nothing. Task: "CloudFormation template for an image-upload pipeline (S3 bucket -> Lambda -> DynamoDB metadata), deployable to dev and prod" — wrote baseline.yaml (94 lines) from general knowledge, then skill.yaml (155 lines) following the body; a YAML parse of both showed baseline had 0 Mappings, 0 Conditions, 0 exported outputs, 0 output Descriptions, no PointInTimeRecovery, no ${AWS::StackName} naming (raw BucketName param instead), while the skill version had EnvironmentConfig mappings driving MemorySize/log retention via !FindInMap, an IsProd condition gating versioning and DeletionPolicy: Retain on 2 resources, 3/3 outputs with Description + Export, PITR enabled, a PK/SK+GSI1 table, a log group with retention, and SourceAccount added to the Lambda permission. Trigger phrasings judged: SHOULD fire — "Write a CloudFormation template for an S3 bucket that triggers a Lambda on upload", "My CloudFormation stack is stuck in DELETE_FAILED, how do I get it unstuck?", "How do I detect drift on the prod stack and see which resources changed?"; SHOULD NOT — "Write a Terraform module for an S3 bucket with versioning", "My Lambda times out on large payloads, help me debug the handler" — 5/5 correct. Docs docked because SKILL.md never references its own template-patterns.md companion (so half the shipped content never loads), and the repo README's Codex install example points at an "rlhf" skill that does not exist in this repo; cfn-lint and the AWS CLI are absent here so neither template was validated against the real service.
- What is the Cloudformation SkillProof Score?
- 8.0/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 6/10, docs & honesty 4/5.
- How do I install Cloudformation?
- Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
- Can I use Cloudformation with Cursor, Copilot, Gemini CLI, Codex or other AI tools?
- The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.