diff --git a/variables.tf b/variables.tf
index 3cf88de..7eeb8ac 100644
--- a/variables.tf
+++ b/variables.tf
@@ -1,73 +1,88 @@
 variable "name" {
-  type = string
-}
-
-variable "domain_name" {
-  type    = string
-  default = null
-}
-
-variable "disk_size" {
-  type    = number
-  default = 1024 * 1024 * 1024 * 15
+  type        = string
+  description = "Hostname of the machine."
 }
 
 variable "admin_authorized_keys" {
   type = list(string)
 }
 
+variable "disk_pool" {
+  type = string
+  description = "Libvirt volume pool for the machine's main disk."
+}
+
+variable "disk_base" {
+  type = string
+  description = "Base image for the machine's operating system."
+}
+
+variable "disk_base_pool" {
+  type = string
+  description = "Libvirt volume pool for the base image of the machine's operating system."
+}
+
+variable "cloudinit_pool" {
+  type = string
+  description = "Libvirt volume pool for the machine's Cloud-init image."
+}
+
+variable "bridge_name" {
+  type = string
+  description = "Host bridge to connect the machine's network interface to."
+}
+
+variable "ca_host" {
+  type = string
+  description = "Host to contact when fetching a SSH host certificate."
+}
+
+variable "domain_name" {
+  type        = string
+  default     = null
+  description = "Libvirt domain name of the machine, as well as the name of related storage media. Reverts to the domain name if undefined."
+}
+
+variable "disk_size" {
+  type        = number
+  default     = 1024 * 1024 * 1024 * 15
+  description = "Size of the machine's main disk."
+}
+
 variable "memory" {
-  type    = number
-  default = 1024
+  type        = number
+  default     = 1024
+  description = "Size of the memory of the machine."
 }
 
 variable "mac" {
   type    = string
   default = null
+  description = "MAC address of the machine's network interface."
 }
 
 variable "insecure_password" {
   type    = bool
   default = false
+  description = "Whether to enable insecure password (for testing purposes). Allows logging in via SSH with `root:root` credentials."
 }
 
 variable "use_host_cert" {
   type    = bool
   default = false
-}
-
-variable "disk_pool" {
-  type = string
-}
-
-variable "disk_base" {
-  type = string
-}
-
-variable "disk_base_pool" {
-  type = string
-}
-
-variable "cloudinit_pool" {
-  type = string
-}
-
-variable "bridge_name" {
-  type = string
-}
-
-variable "ca_host" {
-  type = string
+  description = "Whether this machine should receive a SSH host certificate."
 }
 
 variable "data_disk" {
   type    = string
   default = null
+  description = "Identifier of the machine's persistent data disk."
 }
 
 variable "fixed_address" {
   type    = string
   default = ""
+  description = "Fixed IPv4 address the machine should have."
 }
 
 variable "ansible_command" {
@@ -78,4 +93,5 @@ variable "ansible_command" {
 variable "fixed_dns" {
   type    = string
   default = ""
+  description = "Fixed DNS server the machine should have."
 }