Terraform Operations

Deep dive into the terry tool — all actions, blocked operations, sequential workflows, and workspace management

Updated: March 22, 2026 Edit on GitHub

Terraform Operations Guide

The terry tool is the core of Terry-Form MCP. This guide covers every supported action, how to chain operations, and workspace management.

The terry Tool

Parameters

Parameter	Type	Required	Default	Description
path	string	Yes	—	Workspace path relative to /mnt/workspace
actions	string[]	No	["plan"]	Terraform actions to execute sequentially
vars	object	No	{}	Terraform variables to pass

Example Usage

{
  "tool": "terry",
  "arguments": {
    "path": "environments/dev",
    "actions": ["init", "validate", "plan"],
    "vars": {
      "environment": "development",
      "region": "us-east-1"
    }
  }
}

Supported Actions

init — Initialize Workspace

Downloads providers and sets up the backend.

{"path": "my-project", "actions": ["init"]}

Output: Provider download progress, initialization status.

validate — Validate Configuration

Checks HCL syntax and configuration validity.

{"path": "my-project", "actions": ["validate"]}

Output: Success message or detailed validation errors with file and line numbers.

plan — Generate Execution Plan

Shows what Terraform would do without making changes.

{"path": "my-project", "actions": ["plan"], "vars": {"env": "dev"}}

Output: Plan summary with resource additions, changes, and destructions.

fmt — Format Files

Rewrites Terraform files to canonical format.

{"path": "my-project", "actions": ["fmt"]}

Output: List of formatted files.

show — Show State

Displays the current state of managed resources.

{"path": "my-project", "actions": ["show"]}

graph — Dependency Graph

Generates a DOT-format dependency graph.

{"path": "my-project", "actions": ["graph"]}

providers — List Providers

Shows required and installed providers.

{"path": "my-project", "actions": ["providers"]}

version — Terraform Version

Returns the Terraform version.

{"path": "my-project", "actions": ["version"]}

Blocked Actions

The following actions are permanently blocked and cannot be enabled:

Action	Reason
apply	Modifies real infrastructure
destroy	Deletes real infrastructure
import	Modifies state file
taint	Modifies state file
untaint	Modifies state file

By Design
Blocking destructive operations is a core safety feature. Terry-Form MCP is designed for planning and analysis — actual infrastructure changes should be made through your CI/CD pipeline or manual Terraform runs with proper approvals.

Sequential Workflows

Actions are executed in the order specified. If any action fails, subsequent actions are skipped.

Standard Workflow

{
  "path": "my-project",
  "actions": ["init", "validate", "plan"]
}

Returns results for each action:

{
  "terry-results": [
    {"action": "init", "success": true, "exit_code": 0, "stdout": "..."},
    {"action": "validate", "success": true, "exit_code": 0, "stdout": "..."},
    {"action": "plan", "success": true, "exit_code": 0, "stdout": "..."}
  ]
}

Format and Validate

{
  "path": "my-project",
  "actions": ["fmt", "validate"]
}

Full Analysis Pipeline

Combine terry with analysis tools for comprehensive review:

1. terry with ["init", "validate", "plan"]
2. terry_analyze for best practices
3. terry_security_scan for vulnerabilities
4. terry_recommendations for improvements

Workspace Management

Discovering Workspaces

Use terry_workspace_list to find all workspaces:

{"tool": "terry_workspace_list"}

Returns:

{
  "workspaces": [
    {
      "path": "project-a",
      "initialized": true,
      "has_state": true,
      "providers": ["aws"],
      "modules": 2,
      "last_modified": "2025-01-15T10:30:00Z"
    }
  ]
}

Creating Workspaces

Use terry_workspace_setup to scaffold a new workspace:

{
  "tool": "terry_workspace_setup",
  "arguments": {
    "path": "new-project",
    "project_name": "My New Project"
  }
}

Creates main.tf, variables.tf, and outputs.tf with boilerplate.

Inspecting Workspaces

Use terry_workspace_info for detailed workspace analysis:

{
  "tool": "terry_workspace_info",
  "arguments": {"path": "my-project"}
}

Returns file listings, initialization status, and LSP readiness.

Checking Files

Use terry_file_check to validate individual files:

{
  "tool": "terry_file_check",
  "arguments": {"file_path": "my-project/main.tf"}
}

Passing Variables

Variables are passed as key-value pairs. They map to Terraform’s -var flag:

{
  "path": "my-project",
  "actions": ["plan"],
  "vars": {
    "environment": "production",
    "instance_count": 3,
    "enable_monitoring": true
  }
}

Variable Safety
Variable values are sanitized to prevent injection attacks. Special characters that could be used for command injection are blocked.

Environment Check

Use terry_environment_check to verify the container environment:

{"tool": "terry_environment_check"}

Returns Terraform availability, terraform-ls status, container info, and workspace mount status.

Error Handling

When an action fails, the response includes:

{
  "action": "validate",
  "success": false,
  "exit_code": 1,
  "stderr": "Error: Invalid resource type...",
  "duration": 0.5
}

Common error scenarios:

• Path not found: The workspace path doesn’t exist in /mnt/workspace
• Not initialized: Run init before other actions
• Validation errors: HCL syntax or configuration problems
• Provider errors: Missing or incompatible providers