refactor-module

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 7e824811cd58 · 28 Oct 2026Report an issue or request a re-scan

• Publisherhashicorp GitHub organizationOwner of the repository this skill is read from
• Source folderhashicorp/agent-skills/plugins/terraform/skills/refactor-moduleThe exact folder we audited
• LicenceMPL-2.0As the repository states it
• Commit pinned for this verdict7e824811cd58A new audit runs when the source changes
• Repository statusNot archivedLast push 23 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Transform monolithic Terraform configurations into reusable, maintainable modules following HashiCorp's module design principles and community best practices.

---
name: refactor-module
description: Transform monolithic Terraform configurations into reusable, maintainable modules following HashiCorp's module design principles and community best practices.
metadata:
  lifecycle-status: active
  copyright: Copyright IBM Corp. 2026
  version: "0.0.1"
---

# Skill: Refactor Module

## Overview
This skill guides AI agents in transforming monolithic Terraform configurations into reusable, maintainable modules following HashiCorp's module design principles and community best practices.

## Capability Statement
The agent will analyze existing Terraform code and systematically refactor it into well-structured modules with:
- Clear interface contracts (variables and outputs)
- Proper encapsulation and abstraction
- Versioning and documentation
- Testing frameworks
- Migration path for existing state

## Prerequisites
- Existing Terraform configuration to refactor
- Understanding of resource dependencies
- Access to inspect current state via `terraform state list` / `terraform show -json` (for migration planning)
- Knowledge of module registry patterns

## Input Parameters

| Parameter | Type | Required | Description |
|-----------|------|----------|-------------|
| `source_directory` | string | Yes | Path to existing Terraform configuration |
| `module_name` | string | Yes | Name for the new module |
| `abstraction_level` | string | No | "simple", "intermediate", "advanced" (default: intermediate) |
| `preserve_state` | boolean | Yes | Whether to maintain state compatibility |
| `target_registry` | string | No | Target module registry (local, private, public) |

## Execution Steps

### 1. Analysis Phase
```markdown
**Identify Refactoring Candidates**
- Group resources by logical function
- Identify repeated patterns
- Map resource dependencies
- Detect configuration coupling
- Analyze variable usage patterns

**Complexity Assessment**
- Count resource relationships
- Measure variable propagation depth
- Identify cross-resource references
- Evaluate state migration complexity
```

### 2. Module Design

#### Interface Design
```hcl
# Define clear input contract
variable "network_config" {
  description = "Network configuration parameters"
  type = object({
    cidr_block         = string
    availability_zones = list(string)
    enable_nat         = bool
  })

  validation {
    condition     = can(cidrhost(var.network_config.cidr_block, 0))
    error_message = "CIDR block must be valid IPv4 CIDR."
  }
}

# Define output contract
output "vpc_id" {
  description = "ID of the created VPC"
  value       = aws_vpc.main.id
}

output "private_subnet_ids" {
  description = "List of private subnet IDs"
  value       = { for k, v in aws_subnet.private : k => v.id }
}
```

#### Encapsulation Strategy
```markdown
**What to Include in Module:**
- Tightly coupled resources (VPC + subnets)
- Resources with shared lifecycle
- Configuration with clear boundaries

**What to Keep Separate:**
- Cross-cutting concerns (monitoring, tagging)
- Resources with different lifecycles
- Provider-specific configurations
```

### 3. Code Transformation

#### Before: Monolithic Configuration
```hcl
# main.tf (monolithic)
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
  enable_dns_hostnames = true

  tags = {
    Name = "production-vpc"
    Environment = "prod"
  }
}

resource "aws_subnet" "public_1" {
  vpc_id            = aws_vpc.main.id
  cidr_block        = "10.0.1.0/24"
  availability_zone = "us-east-1a"

  tags = {
    Name = "public-subnet-1"
    Type = "public"
  }
}

resource "aws_subnet" "public_2" {
  vpc_id            = aws_vpc.main.id
  cidr_block        = "10.0.2.0/24"
  availability_zone = "us-east-1b"

  tags = {
    Name = "public-subnet-2"
    Type = "public"
  }
}

resource "aws_internet_gateway" "main" {
  vpc_id = aws_vpc.main.id

  tags = {
    Name = "production-igw"
  }
}

# ... more repetitive subnet and routing resources
```

#### After: Modular Structure
```hcl
# modules/vpc/main.tf
locals {
  subnet_count = length(var.availability_zones)
}

resource "aws_vpc" "main" {
  cidr_block           = var.cidr_block
  enable_dns_hostnames = var.enable_dns_hostnames
  enable_dns_support   = var.enable_dns_support

  tags = merge(
    var.tags,
    {
      Name = var.name
    }
  )
}

resource "aws_subnet" "public" {
  for_each = var.create_public_subnets ? toset(var.availability_zones) : []

  vpc_id                  = aws_vpc.main.id
  cidr_block              = cidrsubnet(var.cidr_block, 8, index(var.availability_zones, each.value))
  availability_zone       = each.value
  map_public_ip_on_launch = true

  tags = merge(
    var.tags,
    {
      Name = "${var.name}-public-${each.value}"
      Type = "public"
    }
  )
}

resource "aws_internet_gateway" "main" {
  count  = var.create_public_subnets ? 1 : 0
  vpc_id = aws_vpc.main.id

  tags = merge(
    var.tags,
    {
      Name = "${var.name}-igw"
    }
  )
}

# modules/vpc/variables.tf
variable "name" {
  description = "Name prefix for all resources"
  type        = string
}

variable "cidr_block" {
  description = "CIDR block for the VPC"
  type        = string

  validation {
    condition     = can(cidrhost(var.cidr_block, 0))
    error_message = "Must be a valid IPv4 CIDR block."
  }
}

variable "availability_zones" {
  description = "List of availability zones"
  type        = list(string)
}

variable "create_public_subnets" {
  description = "Whether to create public subnets"
  type        = bool
  default     = true
}

variable "enable_dns_hostnames" {
  description = "Enable DNS hostnames in the VPC"
  type        = bool
  default     = true
}

variable "enable_dns_support" {
  description = "Enable DNS support in the VPC"
  type        = bool
  default     = true
}

variable "tags" {
  description = "Tags to apply to all resources"
  type        = map(string)
  default     = {}
}

# modules/vpc/outputs.tf
output "vpc_id" {
  description = "ID of the VPC"
  value       = aws_vpc.main.id
}

output "v

Excerpt, first 6,000 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/hashicorp/agent-skills
git -C agent-skills checkout 7e824811cd58

Works in

1. 2026-10-28
   ✓SAFE B 89 / 100

   first audit · source 7e824811cd58

Questions about refactor-module

• github.com/hashicorp/agent-skills/tree/main/plugins/terraform/sk — the audited source at commit 7e824811cd58 and every finding aboveObserved · 28 Oct 2026

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