Ipa Author Stack

ipa-author-stack

Create or update IPA stack skills. Handles the full spectrum of infrastructure authoring: single-service prepare stacks (ECR, Cognito) and multi-service tier stacks (backend, frontend, queue).

User Input

$ARGUMENTS

Expected: [create|update] [name] — e.g., create ml-pipeline, update backend, create ecr. If mode is omitted, infer from file state. If name is omitted, ask the user.

Pre-Execution Checks

1. Read REFERENCE.md for structural contracts and conventions. Keep it in context throughout — all sections are needed during authoring.

2. Detect authoring mode from user input and file state:

   Signal	Mode
   "create a tier", "create a feature", multi-service scenario	Tier stack
   "create a prepare stack", names one AWS service (ECR, SNS, RDS, SES)	Single-service
   Target stack files already exist	Update

3. Confirm the detected mode with the user: "I'll create a [tier stack / single-service prepare stack]. Does that match your intent?"

4. Mode-specific pre-checks:

   • If .claude/skills/ipa.stack.{service}/SKILL.md exists -> update mode. Verify service name does not collide with existing stacks (REFERENCE.md Section 9).
   • Update: Read all existing files in the target directories. Note which files exist and which are absent — absent files will be created.

5. Scan available stack skills: list directories matching .claude/skills/ipa.stack.*/ and confirm each has a SKILL.md.

Execution Steps

Phase 1: Gather Requirements

Applies to: All modes

6. Collect the following from the user, one question at a time. For update mode, pre-populate answers from existing files and ask only about changes.

   a. Architecture overview — "What does this stack deploy, and what is its role in the architecture?" Example: "A queue tier with SQS, DLQ, worker Lambda, and a jobs DynamoDB table"

   b. AWS service and key resources — "What AWS service does this stack deploy?" and "What CloudFormation resource types will the template create?"

   c. Parameters — For each parameter beyond Namespace and Environment, collect:

   • Name, Type, Default value, Validation pattern or allowed values, Error message
   • Classification: Configuration, Wirable — Required, Wirable — Optional, or Pattern-provided (see REFERENCE.md Section 5)
   • For Wirable parameters: which upstream stack and output provides the value

   d. Feature flags (tier stacks) — "Which feature flags should this stack support?" Feature flags control conditional resources within tier stacks (e.g., DynamoDB tables, SQS integration). Defaults are false. Example: Backend with EnablePassengersTable, Queue with EnableJobsTable

   e. Outputs — For each output, collect:

   • Name, Description
   • Used By: which downstream stacks or operational steps consume it

   f. Capabilities — Does the template create IAM resources?

   • If yes -> CAPABILITY_NAMED_IAM
   • If no -> none

   g. Stack name suffix — Confirm suffix for {APP_NAMESPACE}-{APP_ENV}-{suffix}. Default: service name.

   h. Multi-instance support (single-service only) — Can this stack be deployed multiple times with different suffixes?

   i. Build requirements — Does this stack need a pre-built artifact (container image, frontend bundle)?

   j. Security posture — Collect:

   • Deployment IAM actions, Runtime permissions, Security controls, Known deferrals

7. Present a summary of what will be created/updated and confirm before proceeding.

Phase 2: Create CloudFormation Template

8. Create directory infra/cfn/{service}/ if it does not exist.

9. Write infra/cfn/{service}/{service}.yml following the CloudFormation Template Skeleton in REFERENCE.md Section 4:

   • Namespace and Environment parameters with the standard AllowedPattern (copy exactly from REFERENCE.md).
   • Service-specific parameters with appropriate AllowedPattern, AllowedValues, and ConstraintDescription.
   • Conditions section if any Wirable — Optional parameters exist.
   • Resources with !Sub for dynamic naming using ${Namespace} and ${Environment}.
   • Tags on every taggable resource (at minimum: Environment).
   • Outputs exported via Export: Name: !Sub '${AWS::StackName}-{OutputKey}'.
   • For tier stacks: include Enable* feature flag parameters with Conditions, defaulting to false.

10. Validate the template:

    aws cloudformation validate-template --template-body file://infra/cfn/{service}/{service}.yml
    

    • If validation succeeds -> proceed.
    • If validation fails -> fix and re-validate (max 3 iterations).
    • If still failing -> stop and report the validation error.

Phase 3: Create Stack Skill Files

11. Create directory .claude/skills/ipa.stack.{service}/ if it does not exist.

12. Write .claude/skills/ipa.stack.{service}/SKILL.md following REFERENCE.md Section 1. Every section is mandatory except Build Requirements and Naming Convention (include only when applicable):

    • Frontmatter: name: ipa-stack-{service}, description: "{one sentence}"
    • H1 title and summary paragraph
    • CloudFormation Contract (Template, Stack name, Capabilities)
    • Parameters table (Namespace and Environment first, with exact validation from REFERENCE.md)
    • Parameter Classification subsection
    • Outputs table
    • For tier stacks: Feature Flags table and Wirable Parameters table
    • Build Requirements (only if applicable)
    • Naming Convention (only if applicable)
    • Security Summary with links to SECURITY.md

13. Write .claude/skills/ipa.stack.{service}/SECURITY.md following REFERENCE.md Section 2.

14. Write .claude/skills/ipa.stack.{service}/TROUBLESHOOT.md following REFERENCE.md Section 3.

Phase 4: Validate

ultrathink — Shallow validation means the skill ships with inconsistencies that only surface at compose or deploy time.

15. Stack validation:

    • Every parameter in SKILL.md Parameters table exists in the CFN template with matching name, type, and validation.
    • Every output in SKILL.md Outputs table exists in the CFN template with matching export name.
    • Every IAM action in SECURITY.md corresponds to a resource type in the CFN template.
    • Parameter Classification matches actual parameter sources.
    • If template uses CAPABILITY_NAMED_IAM, CloudFormation Contract says so (and vice versa).

16. Compose compatibility:

    • SKILL.md has all four required sections with exact heading names: ## CloudFormation Contract, ## Parameters, ### Parameter Classification, ## Outputs.
    • Parameter table columns: Parameter, Type, Default, Validation, Error Message.
    • Output table columns: Output, Description, Export Convention, Used By.
    • Wirable parameters use the <- arrow notation in Parameter Classification.

17. If any validation fails -> fix the issue and re-validate (max 3 iterations). If unable to fix -> document the issue in the completion report.

Rules

General

• File paths in SKILL.md use relative paths from project root (e.g., infra/cfn/{service}/{service}.yml).
• When updating existing files, preserve content that is not being changed. Do not rewrite unchanged sections.

Stack Rules

• Namespace and Environment parameters are mandatory in every CFN template with the exact AllowedPattern from REFERENCE.md Section 4. No exceptions.
• All CFN outputs must use Export: Name: !Sub '${AWS::StackName}-{OutputKey}'.
• SKILL.md frontmatter name is kebab-case: ipa-stack-{service}.
• Stack name suffix defaults to the service name unless the user specifies otherwise.
• Never create IAM resources without setting Capabilities to CAPABILITY_NAMED_IAM.
• Every Known Deferral must have a Reason and Risk assessment.
• The CFN template directory name and the SKILL.md template path must be consistent: infra/cfn/{service}/{service}.yml.

Completion Report

Created/Updated:

• Template: infra/cfn/{service}/{service}.yml
• Skill: .claude/skills/ipa.stack.{service}/SKILL.md
• Security: .claude/skills/ipa.stack.{service}/SECURITY.md
• Troubleshoot: .claude/skills/ipa.stack.{service}/TROUBLESHOOT.md

Stack Summary:

• Parameters: {count} ({config} configuration, {wirable_req} wirable-required, {wirable_opt} wirable-optional)
• Outputs: {count} exported
• Capabilities: {none or CAPABILITY_NAMED_IAM}

Next steps:

• Validate template: aws cloudformation validate-template --template-body file://infra/cfn/{service}/{service}.yml
• Compose: /ipa-compose
• Deploy: /ipa-deploy