How to fix Error: Argument or block definition required in Terraform

Execute: terraform validate

This command performs syntax checking and provides the exact line number where the error occurs. Note this line number for the next steps.

Open your .tf file and go to the error line. Check if you're trying to assign a value to an argument. The syntax should be:

name = value

Common mistake:

# Wrong - missing = sign
name value

# Correct
name = value

Ensure that blocks like resource, variable, module, etc. have proper opening and closing braces:

# Wrong - missing opening brace
resource "aws_instance" "example"
  ami = "ami-12345"
}

# Correct
resource "aws_instance" "example" {
  ami = "ami-12345"
}

Each block must be enclosed in { }.

Remove any trailing commas after the last item in a block or list:

# Wrong - trailing comma
variable "instance_count" {
  type = number,
}

# Correct
variable "instance_count" {
  type = number
}

All string values must be enclosed in double quotes:

# Wrong - missing quotes
ami = ami-12345

# Correct
ami = "ami-12345"

Execute: terraform fmt -recursive .

This command automatically reformats your HCL and may fix common syntax issues like missing braces or incorrect spacing.

Often the actual syntax error is on a line before the one reported. If the error persists after checking the reported line, examine the 2-3 lines before it. Look for unclosed braces, missing commas between blocks, or other structural issues.