/terraform-skill

name: terraform-skill
description: Use when writing, reviewing, or debugging Terraform/OpenTofu modules, tests, CI, scans, or state ops - diagnoses failure mode (identity churn, secrets, blast radius, CI drift, state corruption) with version-aware guards.
license: Apache-2.0
metadata:
  author: Anton Babenko
  version: 1.17.2

Terraform Skill for Claude

Diagnose-first guidance for Terraform and OpenTofu. Core file is a workflow; depth lives in references loaded on demand.

Response Contract

Every Terraform/OpenTofu response must include:

1. **Assumptions & version floor** — runtime (`terraform` or `tofu`), exact version, providers, state backend, execution path (local/CI/Cloud/Atlantis), environment criticality. State assumptions explicitly if the user did not provide them. 2. **Risk category addressed** — one or more of: identity churn, secret exposure, blast radius, CI drift, compliance gaps, state corruption, provider upgrade risk, testing blind spots. 3. **Chosen remediation & tradeoffs** — what was chosen, what was traded off, why. 4. **Validation plan** — exact commands (`fmt -check`, `validate`, `plan -out`, policy check) tailored to runtime and risk tier. 5. **Rollback notes** — for any destructive or state-mutating change: how to undo, what evidence to keep.

Never recommend direct production apply without a reviewed plan artifact and approval.

Never run `terraform destroy` (targeted or full) without first running `terraform plan -destroy` and showing the user every resource that will be deleted — including implicit dependents pulled in via locals or `for_each`. Get explicit confirmation before proceeding. Never use `-auto-approve` on destroy.

Workflow

1. **Capture execution context** — runtime+version, provider(s), backend, execution path, environment criticality. 2. **Diagnose failure mode(s)** using the routing table below. If intent spans categories, load both references. 3. **Load only the matching reference file(s)** — do not preload depth the task does not need. 4. **Propose fix with risk controls** — why this addresses the mode, what could still go wrong, guardrails (tests/approvals/rollback). 5. **Generate artifacts** — HCL, migration blocks (`moved`, `import`), CI changes, policy rules. 6. **Validate before finalizing** — run validation commands tailored to risk tier. 7. **Emit the Response Contract** at the end.

Diagnose Before You Generate

| Failure category | Symptoms | Primary references | |------------------|----------|--------------------| | **Identity churn** | Resource addresses shift after refactor, `count` index churn, missing `moved` blocks | [Code Patterns: count vs for_each](references/code-patterns.md#count-vs-for_each-deep-dive), [Code Patterns: moved blocks](references/code-patterns.md#moved-blocks-terraform-11), [Code Patterns: LLM mistakes](references/code-patterns.md#llm-mistake-checklist--code-patterns) | | **Secret exposure** | Secrets in defaults, state, logs, CI artifacts | [Security & Compliance](references/security-compliance.md), [Code Patterns: write-only](references/code-patterns.md#write-only-arguments-terraform-111), [State Management](references/state-management.md) | | **Blast radius** | Oversized stacks, shared prod/non-prod state, unsafe applies | [State Management](references/state-management.md), [Module Patterns](references/module-patterns.md) | | **Destroy cascade** | Targeted destroy deletes more than expected; locals referencing a targeted resource make all `for_each` consumers implicit dependents | Response Contract: plan-destroy first; [State Management: Safe Destroy](references/state-management.md#safe-destroy-protocol) | | **CI drift** | Local plan ≠ CI plan, apply without reviewed artifact, unpinned versions | [CI/CD Workflows](references/ci-cd-workflows.md), [Code Patterns: versions](references/code-patterns.md#version-management) | | **Compliance gaps** | Missing policy stage, no approval model, no evidence retention | [Security & Compliance](references/security-compliance.md), [CI/CD Workflows](references/ci-cd-workflows.md) | | **Testing blind spots** | Plan-only validation of computed values, set-type indexing, mock/real confusion | [Testing Frameworks](references/testing-frameworks.md) | | **State corruption / recovery** | Stuck lock, backend migration, drift reconciliation | [State Management](references/state-management.md) | | **Provider upgrade risk** | Breaking-change provider bump, unpinned modules | [Code Patterns: versions](references/code-patterns.md#version-management), [Module Patterns](references/module-patterns.md) | | **Provider lifecycle** | Removing a provider with resources still in state, orphaned resources, `removed` block usage | [State Management: Provider Removal](references/state-management.md#provider-removal) | | **Bootstrap / orchestration misuse** | `null_resource` + `local-exec` for bootstrap, `remote-exec` for setup scripts, provisioner stdout leaking secrets in CI logs | [Code Patterns: Provisioners as Last Resort](references/code-patterns.md#provisioners-as-last-resort) | | **Navigation / safe-rename blind spots** | Cannot locate symbol defs/refs semantically, value-symbol rename done as blind text replace, grep-only refactor missing refs, hallucinated `rg` shim | [Code Intelligence](references/code-intelligence-lsp.md#terraform-ls-capability-matrix) | | **Cross-cloud / provider mapping** | "What's the Azure/GCP equivalent of X", picking a backend/auth model per cloud | [State Management: Cross-cloud equivalents](references/state-management.md#cross-cloud-equivalents) |

When to Use This Skill

**Activate when:** creating or reviewing Terraform/OpenTofu configurations or modules, setting up or debugging tests, structuring multi-environment deployments, implementing IaC CI/CD, choosing module patterns or state organization, configuring or migrating remote state backends.

**Don't use for:** basic HCL syntax questions Claude already knows, provider API referenc