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pantheon-ai/cfn-behavior-validator

Creates test stacks, analyzes CloudFormation events, and compares actual vs documented update behavior to validate whether resource property changes trigger replacement or in-place updates. Use when: a user wants to test if a CFN property change causes resource replacement; when investigating stack update behavior or "Update requires" documentation accuracy; when validating whether a workaround (e.g. hash-based logical IDs) is actually necessary; when questioning UpdateRequiresReplacement behavior for immutable properties; when empirical evidence is needed before an architectural decision involving CDK or CloudFormation stack updates.

Does it follow best practices?

Evaluation100%

1.12x

Agent success when using this tile

Validation for skill structure

Overview
Skills
Evals
Files

rubric.jsonevals/scenario-3/

{
  "context": "Tests whether the agent knows the correct deployment commands, event inspection commands, and process for executing validation tests.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "Initial deployment command",
      "description": "execute-validation.sh includes 'cdk deploy' for initial state",
      "max_score": 8
    },
    {
      "name": "No approval flag",
      "description": "execute-validation.sh uses '--require-approval never' flag on cdk deploy commands",
      "max_score": 10
    },
    {
      "name": "Resource ARN recording",
      "description": "execute-validation.sh includes step to record or note the table ARN/name after initial deployment",
      "max_score": 10
    },
    {
      "name": "Redeploy after change",
      "description": "execute-validation.sh shows making the property change and redeploying",
      "max_score": 8
    },
    {
      "name": "describe-stack-events command",
      "description": "execute-validation.sh or event-analysis.md includes 'aws cloudformation describe-stack-events' command",
      "max_score": 15
    },
    {
      "name": "Resource type filter",
      "description": "The describe-stack-events command uses --query with ResourceType filter (e.g., ResourceType==`AWS::DynamoDB::Table`)",
      "max_score": 12
    },
    {
      "name": "Event field extraction",
      "description": "The --query extracts at least 2 of: Timestamp, ResourceStatus, ResourceStatusReason",
      "max_score": 10
    },
    {
      "name": "Replacement indicators",
      "description": "event-analysis.md explains that DELETE + CREATE events indicate replacement",
      "max_score": 12
    },
    {
      "name": "Update indicators",
      "description": "event-analysis.md explains that UPDATE_IN_PROGRESS/UPDATE_COMPLETE indicate in-place update",
      "max_score": 10
    },
    {
      "name": "Failure handling",
      "description": "event-analysis.md or execute-validation.sh mentions stopping/debugging if deployment fails",
      "max_score": 5
    }
  ]
}

Install with Tessl CLI

npx tessl i pantheon-ai/cfn-behavior-validator

evals

SKILL.md

tile.json