diff --git a/locale/fr/LC_MESSAGES/rougail_output_doc.po b/locale/fr/LC_MESSAGES/rougail_output_doc.po
index d542437..7f8ae56 100644
--- a/locale/fr/LC_MESSAGES/rougail_output_doc.po
+++ b/locale/fr/LC_MESSAGES/rougail_output_doc.po
@@ -5,8 +5,8 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: \n"
-"POT-Creation-Date: 2025-03-30 19:45+0200\n"
-"PO-Revision-Date: 2025-03-30 19:46+0200\n"
+"POT-Creation-Date: 2025-03-31 09:14+0200\n"
+"PO-Revision-Date: 2025-03-31 09:15+0200\n"
 "Last-Translator: \n"
 "Language-Team: \n"
 "Language: fr\n"
@@ -255,8 +255,8 @@ msgid "maximum length for the secret is {0} characters"
 msgstr "longueur maximal pour le secret est de {0} caractères"
 
 #: src/rougail/output_doc/utils.py:88
-msgid "forbidden characters are {0}"
-msgstr "caractères interdits sont {0}"
+msgid "forbidden characters: {0}"
+msgstr "caractères interdits: {0}"
 
 #: src/rougail/output_doc/utils.py:93
 msgid "this filename could be a relative path"
diff --git a/locale/rougail_output_doc.pot b/locale/rougail_output_doc.pot
index 8924f69..edb34e1 100644
--- a/locale/rougail_output_doc.pot
+++ b/locale/rougail_output_doc.pot
@@ -5,7 +5,7 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
-"POT-Creation-Date: 2025-03-30 19:46+0200\n"
+"POT-Creation-Date: 2025-03-31 09:15+0200\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -254,7 +254,7 @@ msgid "maximum length for the secret is {0} characters"
 msgstr ""
 
 #: src/rougail/output_doc/utils.py:88
-msgid "forbidden characters are {0}"
+msgid "forbidden characters: {0}"
 msgstr ""
 
 #: src/rougail/output_doc/utils.py:93
diff --git a/src/rougail/output_doc/doc.py b/src/rougail/output_doc/doc.py
index 7c457b2..a6f0f80 100644
--- a/src/rougail/output_doc/doc.py
+++ b/src/rougail/output_doc/doc.py
@@ -438,7 +438,9 @@ class RougailOutputDoc(Examples):
             if value is None:
                 value = option.impl_get_extra(param)
             if value is not None and value is not False:
-                if isinstance(value, (list, set)):
+                if isinstance(value, set):
+                    value = list(value)
+                if isinstance(value, list):
                     value = display_list(value, add_quote=True)
                 informations.setdefault("validators", []).append(msg.format(value))
         # get validation information from annotator
diff --git a/src/rougail/output_doc/locale/fr/LC_MESSAGES/rougail_output_doc.mo b/src/rougail/output_doc/locale/fr/LC_MESSAGES/rougail_output_doc.mo
index 1282998..4a8f2a6 100644
Binary files a/src/rougail/output_doc/locale/fr/LC_MESSAGES/rougail_output_doc.mo and b/src/rougail/output_doc/locale/fr/LC_MESSAGES/rougail_output_doc.mo differ
diff --git a/src/rougail/output_doc/utils.py b/src/rougail/output_doc/utils.py
index 37b6f53..9683df6 100644
--- a/src/rougail/output_doc/utils.py
+++ b/src/rougail/output_doc/utils.py
@@ -85,7 +85,7 @@ DocTypes = {
         "params": {
             "min_len": _("minimum length for the secret is {0} characters"),
             "max_len": _("maximum length for the secret is {0} characters"),
-            "forbidden_char": _("forbidden characters are {0}"),
+            "forbidden_char": _("forbidden characters: {0}"),
         },
     },
     "unix_filename": {
diff --git a/tests/results/test/00_6secret_param.adoc b/tests/results/test/00_6secret_param.adoc
index 089e337..c6683bd 100644
--- a/tests/results/test/00_6secret_param.adoc
+++ b/tests/results/test/00_6secret_param.adoc
@@ -15,7 +15,18 @@ The second variable. +
 **Validators**: 
 
 * maximum length for the secret is 10 characters
-* forbidden characters are "$" and "^"
+* 'forbidden characters: "$" and "^"'
+
+**Default**: value               
+| 
+
+**secret3** +
+`https://rougail.readthedocs.io/en/latest/variable.html#variables-types[secret]` `standard` `mandatory`            | 
+The third variable. +
+**Validators**: 
+
+* maximum length for the secret is 10 characters
+* 'forbidden characters: "$"'
 
 **Default**: value               
 |====
diff --git a/tests/results/test/00_6secret_param.json b/tests/results/test/00_6secret_param.json
index 03147ca..8a56b9c 100644
--- a/tests/results/test/00_6secret_param.json
+++ b/tests/results/test/00_6secret_param.json
@@ -47,7 +47,7 @@
     ],
     "validators": [
       "maximum length for the secret is 10 characters",
-      "forbidden characters are \"$\" and \"^\""
+      "forbidden characters: \"$\" and \"^\""
     ],
     "paths": [
       "secret2"
@@ -58,5 +58,36 @@
     "descriptions": [
       "The second variable."
     ]
+  },
+  "secret3": {
+    "type": "variable",
+    "default": "value",
+    "properties": [
+      {
+        "type": "type",
+        "name": "secret"
+      },
+      {
+        "type": "mode",
+        "name": "standard"
+      },
+      {
+        "type": "property",
+        "name": "mandatory"
+      }
+    ],
+    "validators": [
+      "maximum length for the secret is 10 characters",
+      "forbidden characters: \"$\""
+    ],
+    "paths": [
+      "secret3"
+    ],
+    "names": [
+      "secret3"
+    ],
+    "descriptions": [
+      "The third variable."
+    ]
   }
 }
\ No newline at end of file
diff --git a/tests/results/test/00_6secret_param.md b/tests/results/test/00_6secret_param.md
index 73881ca..f022c21 100644
--- a/tests/results/test/00_6secret_param.md
+++ b/tests/results/test/00_6secret_param.md
@@ -1,5 +1,6 @@
 | Variable&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   | Description&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   |
 |------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | **secret1**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `basic` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | The first variable.<br/>**Validator**: minimum length for the secret is 10 characters                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
-| **secret2**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | The second variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters are "$" and "^"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+| **secret2**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | The second variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters: "$" and "^"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+| **secret3**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | The third variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters: "$"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
 
diff --git a/tests/results/test/00_6secret_param.sh b/tests/results/test/00_6secret_param.sh
index 61c6f7e..bcf6dbf 100644
--- a/tests/results/test/00_6secret_param.sh
+++ b/tests/results/test/00_6secret_param.sh
@@ -9,7 +9,13 @@
 β”‚  secret   standard   mandatory        β”‚ Validators:                          β”‚
 β”‚                                       β”‚ - maximum length for the secret is   β”‚
 β”‚                                       β”‚ 10 characters                        β”‚
-β”‚                                       β”‚ - forbidden characters are "$" and   β”‚
-β”‚                                       β”‚ "^"                                  β”‚
+β”‚                                       β”‚ - forbidden characters: "$" and "^"  β”‚
+β”‚                                       β”‚ Default: value                       β”‚
+β”œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€
+β”‚ secret3                               β”‚ The third variable.                  β”‚
+β”‚  secret   standard   mandatory        β”‚ Validators:                          β”‚
+β”‚                                       β”‚ - maximum length for the secret is   β”‚
+β”‚                                       β”‚ 10 characters                        β”‚
+β”‚                                       β”‚ - forbidden characters: "$"          β”‚
 β”‚                                       β”‚ Default: value                       β”‚
 β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜
diff --git a/tests/results/test_examples/00_6secret_param.md b/tests/results/test_examples/00_6secret_param.md
index 837d6f4..5a3d282 100644
--- a/tests/results/test_examples/00_6secret_param.md
+++ b/tests/results/test_examples/00_6secret_param.md
@@ -10,4 +10,5 @@ secret1: secrets
 ---
 secret1: secrets
 secret2: value
+secret3: value
 ```
diff --git a/tests/results/test_namespace/00_6secret_param.adoc b/tests/results/test_namespace/00_6secret_param.adoc
index bd609c0..b6f7bf7 100644
--- a/tests/results/test_namespace/00_6secret_param.adoc
+++ b/tests/results/test_namespace/00_6secret_param.adoc
@@ -17,7 +17,18 @@ The second variable. +
 **Validators**: 
 
 * maximum length for the secret is 10 characters
-* forbidden characters are "$" and "^"
+* 'forbidden characters: "$" and "^"'
+
+**Default**: value               
+| 
+
+**rougail.secret3** +
+`https://rougail.readthedocs.io/en/latest/variable.html#variables-types[secret]` `standard` `mandatory`            | 
+The third variable. +
+**Validators**: 
+
+* maximum length for the secret is 10 characters
+* 'forbidden characters: "$"'
 
 **Default**: value               
 |====
diff --git a/tests/results/test_namespace/00_6secret_param.json b/tests/results/test_namespace/00_6secret_param.json
index ae80755..abc6ab1 100644
--- a/tests/results/test_namespace/00_6secret_param.json
+++ b/tests/results/test_namespace/00_6secret_param.json
@@ -65,7 +65,7 @@
         ],
         "validators": [
           "maximum length for the secret is 10 characters",
-          "forbidden characters are \"$\" and \"^\""
+          "forbidden characters: \"$\" and \"^\""
         ],
         "paths": [
           "rougail.secret2"
@@ -76,6 +76,37 @@
         "descriptions": [
           "The second variable."
         ]
+      },
+      "rougail.secret3": {
+        "type": "variable",
+        "default": "value",
+        "properties": [
+          {
+            "type": "type",
+            "name": "secret"
+          },
+          {
+            "type": "mode",
+            "name": "standard"
+          },
+          {
+            "type": "property",
+            "name": "mandatory"
+          }
+        ],
+        "validators": [
+          "maximum length for the secret is 10 characters",
+          "forbidden characters: \"$\""
+        ],
+        "paths": [
+          "rougail.secret3"
+        ],
+        "names": [
+          "secret3"
+        ],
+        "descriptions": [
+          "The third variable."
+        ]
       }
     }
   }
diff --git a/tests/results/test_namespace/00_6secret_param.md b/tests/results/test_namespace/00_6secret_param.md
index 177706c..fc32da6 100644
--- a/tests/results/test_namespace/00_6secret_param.md
+++ b/tests/results/test_namespace/00_6secret_param.md
@@ -3,5 +3,6 @@
 | Variable&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   | Description&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   |
 |------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | **rougail.secret1**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `basic` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | The first variable.<br/>**Validator**: minimum length for the secret is 10 characters                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
-| **rougail.secret2**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | The second variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters are "$" and "^"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                        |
+| **rougail.secret2**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | The second variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters: "$" and "^"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+| **rougail.secret3**<br/>[`secret`](https://rougail.readthedocs.io/en/latest/variable.html#variables-types) `standard` `mandatory`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | The third variable.<br/>**Validators**: <br/>- maximum length for the secret is 10 characters<br/>- forbidden characters: "$"<br/>**Default**: value                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
 
diff --git a/tests/results/test_namespace/00_6secret_param.sh b/tests/results/test_namespace/00_6secret_param.sh
index 452f46f..c48f2c2 100644
--- a/tests/results/test_namespace/00_6secret_param.sh
+++ b/tests/results/test_namespace/00_6secret_param.sh
@@ -14,7 +14,13 @@
 β”‚  secret   standard   mandatory        β”‚ Validators:                          β”‚
 β”‚                                       β”‚ - maximum length for the secret is   β”‚
 β”‚                                       β”‚ 10 characters                        β”‚
-β”‚                                       β”‚ - forbidden characters are "$" and   β”‚
-β”‚                                       β”‚ "^"                                  β”‚
+β”‚                                       β”‚ - forbidden characters: "$" and "^"  β”‚
+β”‚                                       β”‚ Default: value                       β”‚
+β”œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€
+β”‚ rougail.secret3                       β”‚ The third variable.                  β”‚
+β”‚  secret   standard   mandatory        β”‚ Validators:                          β”‚
+β”‚                                       β”‚ - maximum length for the secret is   β”‚
+β”‚                                       β”‚ 10 characters                        β”‚
+β”‚                                       β”‚ - forbidden characters: "$"          β”‚
 β”‚                                       β”‚ Default: value                       β”‚
 β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜
diff --git a/tests/results/test_namespace_examples/00_6secret_param.md b/tests/results/test_namespace_examples/00_6secret_param.md
index 5230468..ab0e61b 100644
--- a/tests/results/test_namespace_examples/00_6secret_param.md
+++ b/tests/results/test_namespace_examples/00_6secret_param.md
@@ -12,4 +12,5 @@ rougail:
 rougail:
   secret1: secrets
   secret2: value
+  secret3: value
 ```