tofu-assist 0.2.8

Natural language → validated, secured, cost-estimated OpenTofu config

tofu-assist

Writing Terraform is slow. Reading terraform plan output is unreadable. tofu-assist fixes both.

Describe your infrastructure in plain English. Get validated, security-scanned, cost-estimated OpenTofu config — with a single approve step before anything touches your cloud.

$ tofu-assist "I need a k8s cluster with postgres in eu-west-1"

Provider: aws (eu-west-1)
Generating configuration...

   ✓ main.tf (47 lines)
   ✓ variables.tf (11 lines)
   ✓ outputs.tf (8 lines)

Security scan: ✓ no issues found

Running tofu plan...

SUMMARY
  9 resources: 9 will be created.
  Estimated cost: $187/month

ATTENTION REQUIRED
  (none)

WHAT WILL BE BUILT
  + main (VPC)
  + 2x public (subnet)
  + 2x private (subnet)
  + main (EKS cluster)
  + main (EKS node group)
  + main (RDS instance)
  ...

Apply this? [y/N]

Install

Prerequisites

• OpenTofu (install guide) — the open-source Terraform fork
• Python 3.10+
• An API key for any OpenAI-compatible LLM (DeepSeek, OpenAI, Anthropic, OpenCode, etc.)

Quickstart

pip install tofu-assist
export TOFU_ASSIST_API_KEY=your_api_key
tofu-assist "I need a load balancer with two EC2 instances"

Optional dependencies

Tool	Purpose	Install
Infracost	Cost estimation before apply	curl -fsSL https://raw.githubusercontent.com/infracost/infracost/master/scripts/install.sh | sh
Checkov	Static security scanning	pip install checkov

The pipeline degrades gracefully — missing tools are skipped with a note, never an error.

What it does

Three layers. One pipeline.

Layer	What you get
Generate	Plain English → production-quality HCL. Security defaults baked in: encryption at rest, blocked public S3, no wildcard IAM, no 0.0.0.0/0 on sensitive ports. One retry if validation fails.
Verify	Static security scan (Checkov) catches bad defaults before plan. Plan explainer turns 500-line JSON into a 3-section summary. Cost estimate (Infracost) tells you the monthly bill before you approve.
Approve	Hard-stop on production resource destruction. Tag-only changes are silent. y/N gate with everything visible.

Subcommands

tofu-assist explain — understand any codebase instantly

Point at any directory with .tf files and get a plain-English summary.

$ tofu-assist explain ./infra

Analyzing /home/user/infra...

──────────────────────────────────────────────────────────
CODEBASE EXPLANATION
──────────────────────────────────────────────────────────

OVERVIEW
A production EKS cluster with RDS Postgres in a custom VPC
across 3 AZs. Public-facing via ALB with WAF.

RESOURCES (12)
  • main_vpc (aws_vpc)
    VPC with 10.0.0.0/16 CIDR for all resources
  • public_subnet_a (aws_subnet)
    Public subnet in us-east-1a for load balancer
  • ...

ARCHITECTURE
Internet → WAF → ALB → EKS (private subnets) → RDS (private subnets)

SECURITY NOTES
  ⚠ RDS is publicly accessible — consider restricting
  ⚠ Security group allows 0.0.0.0/0 on port 5432

COST IMPLICATIONS
  💰 EKS cluster: ~$73/month base
  💰 RDS db.r5.large (multi-AZ): ~$400/month

SUGGESTIONS
  → Add encryption at rest for RDS
  → Add lifecycle policies for S3 buckets
  → Tag all resources with Environment and Team

Options:

• --detailed — deeper security and cost analysis
• --json — machine-readable JSON output

tofu-assist edit — modify existing config via natural language

Don't rewrite configs. Tell them what to change.

$ tofu-assist edit "add a read replica to the RDS instance"

Editing /home/user/infra...
Instruction: add a read replica to the RDS instance

Changes:
--- a/main.tf
+++ b/main.tf
@@ -45,6 +45,14 @@
   skip_final_snapshot = true
 }

+resource "aws_db_instance" "read_replica" {
+  replicate_source_db = aws_db_instance.main.identifier
+  instance_class      = "db.r5.large"
+}
+

Apply these changes? [y/N] y
✓ Modified 1 file(s): main.tf
  Backup saved to: ~/.tofu-assist/backups/

Next steps:
  cd /home/user/infra && tofu plan    # review the plan
  tofu apply                 # apply changes

Options:

• --dir — specify target directory
• --dry-run — preview changes without applying
• --yes / -y — skip approval prompt

How it works

You: "I need a k8s cluster with postgres"
         │
         ▼
   ┌─────────────────┐
   │  LLM generation  │  System prompt enforces security defaults.
   │  (DeepSeek/any)  │  JSON envelope, no markdown parsing.
   └────────┬────────┘
            │  main.tf, variables.tf, outputs.tf
            ▼
   ┌─────────────────┐
   │  Checkov scan    │  Static analysis. CRITICAL findings surfaced.
   │  (optional)      │  Encryption, public access, wildcard IAM.
   └────────┬────────┘
            │
            ▼
   ┌─────────────────┐
   │  tofu plan       │  OpenTofu validates and produces plan JSON.
   └────────┬────────┘
            │
            ▼
   ┌─────────────────┐
   │  explain layer   │  SUMMARY + ATTENTION REQUIRED + WHAT WILL BE BUILT.
   │  + Infracost     │  Estimated cost injected inline.
   └────────┬────────┘
            │
            ▼
   ┌─────────────────┐
   │  Approve? [y/N]  │  Hard-stop on production resource destruction.
   └─────────────────┘

Edit flow

You: "add a read replica to the RDS"
         │
         ▼
   ┌─────────────────┐
   │  Read existing    │  All .tf files from target directory.
   │  config files     │  Hidden files and plan.json skipped.
   └────────┬────────┘
            │
            ▼
   ┌─────────────────┐
   │  LLM edit         │  System prompt preserves all unchanged
   │  (DeepSeek/any)   │  resources. Only modifies what the
   └────────┬────────┘  instruction targets.
            │
            ▼
   ┌─────────────────┐
   │  Show diff        │  Unified diff of changes across all files.
   │  + tofu validate  │  Validation with auto-retry on failure.
   └────────┬────────┘
            │
            ▼
   ┌─────────────────┐
   │  Approve? [y/N]   │  Backs up originals to ~/.tofu-assist/backups/.
   │                   │  Overwrites on approval. Dry-run available.
   └─────────────────┘

Safety features

• Security defaults in the system prompt — encryption at rest, blocked public S3, no wildcard IAM, restricted security groups. The LLM generates secure config by default.
• Checkov static scan — catches bad defaults before plan runs. CRITICAL findings are always surfaced. Noise is swallowed.
• Production risk detection — destroying aws_db_instance.production is a hard stop. Destroying aws_subnet.main is a warning. The classification weighs resource type AND naming patterns.
• Alarming plan detection — 15+ deletions or high destroy ratio refuses auto-summary. Single production database destroy triggers hard stop.
• Tag-only filtering — tag changes are silent. The ATTENTION REQUIRED section stays trustworthy.
• Never blocks on tool failures — Infracost not installed? Shows "cost estimate unavailable." Checkov not installed? Skips scan. The pipeline degrades gracefully.

Files

~/.tofu-assist/
├── pending/                    ← Generation lands here
│   └── 2024-01-15-143022/
│       ├── main.tf
│       ├── variables.tf
│       ├── outputs.tf
│       └── plan.json
└── applied/                    ← Successful applies archived here
    └── 2024-01-15-143045/
        └── ...

Configuration

Variable	Default	Purpose
TOFU_ASSIST_API_KEY	$DEEPSEEK_API_KEY	LLM API key (required)
TOFU_ASSIST_API_BASE	https://api.deepseek.com/v1	OpenAI-compatible API endpoint
TOFU_ASSIST_MODEL	deepseek-chat	Model name

Provider examples

# DeepSeek (default)
export TOFU_ASSIST_API_KEY=sk-...

# OpenAI
export TOFU_ASSIST_API_KEY=sk-...
export TOFU_ASSIST_API_BASE=https://api.openai.com/v1
export TOFU_ASSIST_MODEL=gpt-4o

# Anthropic (via compatible proxy)
export TOFU_ASSIST_API_KEY=sk-ant-...
export TOFU_ASSIST_API_BASE=https://api.anthropic.com/v1
export TOFU_ASSIST_MODEL=claude-sonnet-4-20250514

# OpenCode Go
export TOFU_ASSIST_API_KEY=oc-...
export TOFU_ASSIST_API_BASE=https://api.opencode.ai/zen/go/v1
export TOFU_ASSIST_MODEL=deepseek-v4-flash

File structure

~/.tofu-assist/
├── pending/                    ← Generated configs land here before approval
│   ├── 2024-01-15-143022/      ← Fresh generation
│   └── edit-2024-01-15-150000/ ← Edit preview
│       ├── main.tf
│       ├── variables.tf
│       ├── outputs.tf
│       └── plan.json
├── applied/                    ← Successfully applied configs archived here
│   └── 2024-01-15-143045/
└── backups/                    ← Originals backed up before edit overwrites
    └── 2024-01-15-150000/

Why?

Coding agents can generate Terraform. But they can't validate it, scan it for security issues, estimate what it'll cost, or stop you from destroying production. tofu-assist does all of that, plus lets you edit existing configs and explain any codebase — not just generate from scratch.

"Try generating a production EKS cluster with RDS in Claude Code. Now check: is the DB encrypted? Are the security groups locked down? Do you know what it'll cost? What happens if you run apply? Exactly."

Why OpenTofu

OpenTofu is the community fork of Terraform (Apache 2.0), created after HashiCorp's license change to BUSL. tofu-assist bets on OpenTofu — the ecosystem that's growing, not the one that changed the rules.

Contributing

See CONTRIBUTING.md for development setup, testing, and PR guidelines.

git clone https://github.com/tofu-assist/tofu-assist.git
cd tofu-assist
pip install -e ".[dev]"
python -m pytest -v

License

MIT