Cursor Agent is a practical fit for Terraform work because it operates inside the repo, reads HCL directly, and can run terraform fmt, terraform validate, and terraform plan before you review changes. Start cursor-agent in the project folder and give it explicit Terraform guardrails in AGENTS.md or .cursor/rules. For base agent setup, see Cursor Agent.
A plan-first tool for infrastructure as code
Terraform is largely declarative: most changes are edits to .tf files, variable blocks, outputs, and provider configurations. Cursor Agent can make those edits consistently and check them with the same terraform binary you already use. It is not just a code generator; because it runs in the project directory, it can run terraform plan and show you the resource diff before anything is applied. That closes the loop that matters in infrastructure work: proposal, validation, plan, review.
The concrete benefits are:
- Module boilerplate: variables with types and defaults, outputs,
versions.tf, and provider requirements follow your project conventions. - Cross-file changes: it can add a resource, update an IAM policy document, and add a new output without losing track of dependencies.
- Safe local iteration:
terraform validateandplanrun in the terminal, so the agent can fix mistakes immediately. - Consistent style: you can enforce
terraform fmtand naming rules through AGENTS.md.
The main prerequisite is a clear project contract. Without it, an agent may race ahead into apply, state changes, or provider upgrades. With the setup below, the same strengths work in your favor.
Put Terraform guardrails in AGENTS.md
Create or update AGENTS.md in the repo root, or use .cursor/rules if you prefer rule files. The goal is to encode the commands you expect the agent to run, the folder layout, and the Terraform-specific safety limits. Keep the file short; agents follow explicit, current instructions better than long prose. If you need the terminal workflow, the How to use Cursor CLI: a step-by-step guide is useful.
A realistic starting point:
# Terraform repo rules
- Terraform CLI: ~> 1.8
- Providers are pinned in `versions.tf`. Do not change provider source or version without asking.
- Folder layout:
- `modules/<name>/` contains `main.tf`, `variables.tf`, `outputs.tf`
- `environments/<env>/` contains `main.tf`, `backend.tf`, `terraform.tfvars`
- Lint and validation:
- Run `terraform fmt -check` and fix any formatting.
- Run `tflint --recursive` if available.
- Run `terraform validate` before any plan.
- Plan and apply:
- Always run `terraform plan -out=plan.tfplan` and show the diff.
- Never run `terraform apply` unless the user explicitly requests it after reviewing the plan.
- State and backend:
- Do not edit state files or run `terraform state` commands without an explicit request.
- Remote state/backend configuration changes require user confirmation.
This tells the agent where modules live, how to check its work, and where the hard stops are.
The daily loop: small tasks, plan, review
Use the same loop for most Terraform tasks: plan the change in one sentence, let the agent edit, run validation, review the plan, then decide on apply.
Steps:
- Give the agent a bounded task: one module, one resource, or one refactor.
- Ask it to run
terraform fmt -check,terraform validate, andterraform planbefore considering the task done. - Read the plan output in the terminal. Check for unexpected replacements, deletions, or changes to remote state.
- Review
git difffor the.tfand lock file changes. - If the plan is acceptable, run
terraform applyyourself or ask the agent to apply with explicit confirmation.
Example prompts that fit this loop:
- Add a
tls_private_keyresource and a sensitive output tomodules/bootstrap; update the input variables foralgorithmandrsa_bits; run validation and plan. - Create a new module
modules/s3_websitewith variables forbucket_nameandindex_document, and outputs forwebsite_endpointandbucket_arn. - Refactor
environments/prodto useterraform.tfvarsinstead of inline variable defaults; run plan and confirm no resource changes are proposed. - Update the Lambda execution role policy to include
logs:CreateLogGroupandlogs:PutLogEvents; run validate and plan. - Change the AWS provider version constraint in
versions.tffrom~> 5.0to~> 5.30; runterraform init -upgradeand plan; report any resources that would be replaced.
Where Cursor Agent helps and where to verify closely
Well-suited tasks:
- Adding or updating resources within an existing module: create an S3 bucket, enable versioning, add tags, attach a policy.
- Generating standard module scaffolding with inputs, outputs, and provider requirements.
- Refactoring variable naming, defaults, and type constraints across environments.
- Updating IAM policy documents and security group rules with JSON/HCL conversions.
- Writing
terraform testassertions for validation rules and plan checks.
Pitfalls to watch closely:
- State and backend edits: the agent may try to change backend configuration or run
terraform state mv/rmwithout enough context. - Provider upgrades: changing provider versions can force replacements; require a plan and explicit review.
- Multi-environment drift: a generic task may update
devcorrectly but missprodconventions; pin the environment. - Output and sensitive data: the agent may print private keys or passwords unless you mark outputs
sensitiveand instruct it to avoid echoing values. - Lock file changes:
terraform init -upgradecan alter.terraform.lock.hcl; review that diff separately. - Dynamic blocks and
count/for_each: the agent may introduce patterns that look valid but change resource indexes and cause replacements.
In general, keep tasks small and ask for the plan diff. The agent is good at Terraform syntax, but it cannot know your risk tolerance for infrastructure changes unless you encode it.
Validate and plan before you trust a change
Terraform has built-in validation and plan commands that should be part of every agent task. Add tflint or checkov for policy checks if they are already in the project. Do not let the agent treat terraform apply as a test.
Use this table as a verification checklist:
| Check | Command or action | Why it matters |
|---|---|---|
| Formatting | terraform fmt -check | Keeps HCL style consistent and diffs readable |
| Syntax and references | terraform validate | Catches invalid resource arguments and missing variables |
| Resource changes | terraform plan -out=plan.tfplan | Shows adds, changes, and replacements before apply |
| Static analysis | tflint --recursive | Finds deprecated arguments, provider issues, and common mistakes |
| Lock file review | git diff .terraform.lock.hcl | Confirms provider version changes are intentional |
After the agent runs the first three, always read the plan output yourself. If the task includes policy changes, ask the agent to run checkov -d . or your existing scanner and fix high-severity findings first. Terraform terraform test can be useful for module validation, but it does not replace a real plan against a target environment.
Parallel Terraform work with AgentVera
AgentVera lets you run Cursor Agent alongside other CLI agents in separate terminals, which is useful when Terraform work splits into independent modules or environments. Because each agent can use its own git worktree, they won’t overwrite each other’s .tf files or lock changes; plan diffs remain isolated. Automatic code review after each turn catches risky resource or state edits, and checkpoints let you undo a bad agent turn and replay it step by step before any apply. See Best tools to run AI coding agents in parallel (2026) for a broader comparison.
Final word
Cursor Agent works well with Terraform when the repo has clear rules and the loop stays plan-first. Keep AGENTS.md short and specific, make the agent show a plan for every change, and review git diff before apply. For parallel modules or environments, use AgentVera worktrees and automatic review to keep infrastructure changes isolated and reversible.