diff --git a/roles/certbot/README.md b/roles/certbot/README.md
index 3ad35bf..4cbd465 100644
--- a/roles/certbot/README.md
+++ b/roles/certbot/README.md
@@ -8,15 +8,7 @@ Also see the following documentation for a full How-to on how to get certificate
 
 ## Required Arguments
 
-- `certbot__acme_account_email_address`: The E-Mail address to use for the ACME account.
-
-## Optional Arguments
-
-- `certbot__certificate_domains`: The domains for which to obtain a certificate using the HTTP-01 challenge.
-- `certbot__http_01_port`: The port number the bot listens on. Should be `80` if directly exposed to the internet.  
-   Defaults to `31820` (for the public-reverse-proxy setup).
-- `certbot__new_cert_commands`: A list of commands to execute after getting a new certificate. Will be added into a bash script.  
-  Defaults to the empty list (`[ ]`).
+For the required arguments look at the [`argument_specs.yaml`](./meta/argument_specs.yaml).
 
 ## `hosts`
 
diff --git a/roles/certbot/defaults/main.yaml b/roles/certbot/defaults/main.yaml
index 9e6551e..9b20634 100644
--- a/roles/certbot/defaults/main.yaml
+++ b/roles/certbot/defaults/main.yaml
@@ -1,3 +1,2 @@
-certbot__certificate_domains: [ ]
 certbot__http_01_port: 31820
 certbot__new_cert_commands: [ ]
diff --git a/roles/certbot/meta/argument_specs.yaml b/roles/certbot/meta/argument_specs.yaml
index b895b5f..b2b3f32 100644
--- a/roles/certbot/meta/argument_specs.yaml
+++ b/roles/certbot/meta/argument_specs.yaml
@@ -2,18 +2,25 @@ argument_specs:
   main:
     options:
       certbot__acme_account_email_address:
+        description: The E-Mail address to give to certbot for the ACME account.
         type: str
         required: true
       certbot__certificate_domains:
+        description: The domains for which to obtain a certificate.
         type: list
         elements: str
-        required: false
-        default: [ ]
+        required: true
       certbot__http_01_port:
+        description: |
+          The port number the bot listens on. Must be 80 if directly exposed to the internet.
+          Default is 31820 for the public-reverse-proxy setup.
         type: str
         required: false
         default: 31820
       certbot__new_cert_commands:
+        description: >-
+          A list of commands to execute after getting a new certificate.
+          Will be added into a bash script.
         type: list
         elements: str
         required: false