diff --git a/CHANGELOG.md b/CHANGELOG.md
index 969f95ffc..4ee5f3f44 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Fixed
+- [jsonschema] Fix PickleTable.argumentIndex docs ([#488](https://github.com/cucumber/messages/pull/488))
 
 ## [34.1.0] - 2026-07-15
 ### Added
diff --git a/dart/lib/src/generated/pickle_table.g.dart b/dart/lib/src/generated/pickle_table.g.dart
index 980e1dc17..9f0069a2d 100644
--- a/dart/lib/src/generated/pickle_table.g.dart
+++ b/dart/lib/src/generated/pickle_table.g.dart
@@ -6,7 +6,7 @@ part of 'messages.dart';
 
 /// Generated Dart representation of the [PickleTable message](https://github.com/cucumber/messages/blob/main/jsonschema/src/PickleTable.schema.json) in Cucumber's [message protocol](https://github.com/cucumber/messages).
 class PickleTable {
-  /// The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+  /// The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
   final int? argumentIndex;
   /// The `rows` property.
   final List<PickleTableRow> rows;
diff --git a/dotnet/Cucumber.Messages/generated/PickleTable.cs b/dotnet/Cucumber.Messages/generated/PickleTable.cs
index c3db1f293..b31aad5f3 100644
--- a/dotnet/Cucumber.Messages/generated/PickleTable.cs
+++ b/dotnet/Cucumber.Messages/generated/PickleTable.cs
@@ -17,7 +17,7 @@ namespace Io.Cucumber.Messages.Types;
 public sealed class PickleTable 
 {
     /**
-     * The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+     * The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
      */
     public Nullable<long> ArgumentIndex { get; private set; }
     public List<PickleTableRow> Rows { get; private set; }
diff --git a/java/src/generated/java/io/cucumber/messages/types/PickleTable.java b/java/src/generated/java/io/cucumber/messages/types/PickleTable.java
index e931388c2..92d7bb1f7 100644
--- a/java/src/generated/java/io/cucumber/messages/types/PickleTable.java
+++ b/java/src/generated/java/io/cucumber/messages/types/PickleTable.java
@@ -27,7 +27,7 @@ public PickleTable(
     }
 
     /**
-     * The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+     * The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
      */
     public Optional<Integer> getArgumentIndex() {
         return Optional.ofNullable(argumentIndex);
diff --git a/jsonschema/messages.md b/jsonschema/messages.md
index 276529674..c987d6377 100644
--- a/jsonschema/messages.md
+++ b/jsonschema/messages.md
@@ -1324,7 +1324,7 @@ Optional arguments. Either a PickleDocString, PickleTable or both
 * Type: integer 
 * Required: no 
 
-The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
 
 #### PickleTable.rows 
 
diff --git a/jsonschema/messages.schema.json b/jsonschema/messages.schema.json
index 3830a6d8e..3abcc5814 100644
--- a/jsonschema/messages.schema.json
+++ b/jsonschema/messages.schema.json
@@ -1072,7 +1072,7 @@
           ],
           "properties": {
             "argumentIndex": {
-              "description": "The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.",
+              "description": "The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.",
               "type": "integer",
               "minimum": 1,
               "maximum": 2
diff --git a/jsonschema/src/Pickle.schema.json b/jsonschema/src/Pickle.schema.json
index f236c66a8..0b5917af9 100644
--- a/jsonschema/src/Pickle.schema.json
+++ b/jsonschema/src/Pickle.schema.json
@@ -86,7 +86,7 @@
       ],
       "properties": {
         "argumentIndex":{
-          "description": "The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.",
+          "description": "The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.",
           "type": "integer",
           "minimum": 1,
           "maximum": 2
diff --git a/perl/lib/Cucumber/Messages.pm b/perl/lib/Cucumber/Messages.pm
index 594fa03ef..565f5d7e4 100644
--- a/perl/lib/Cucumber/Messages.pm
+++ b/perl/lib/Cucumber/Messages.pm
@@ -3238,7 +3238,7 @@ sub _types {
 
 =head4 argument_index
 
-The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
 =cut
 
 has argument_index =>
diff --git a/php/src-generated/PickleTable.php b/php/src-generated/PickleTable.php
index b6ebe01fa..c683a0122 100644
--- a/php/src-generated/PickleTable.php
+++ b/php/src-generated/PickleTable.php
@@ -28,7 +28,7 @@ final class PickleTable implements JsonSerializable
     public function __construct(
 
         /**
-         * The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+         * The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
          */
         public readonly ?int $argumentIndex = null,
         public readonly array $rows = [],
diff --git a/python/src/cucumber_messages/_messages.py b/python/src/cucumber_messages/_messages.py
index 150dc5a7e..118594211 100644
--- a/python/src/cucumber_messages/_messages.py
+++ b/python/src/cucumber_messages/_messages.py
@@ -477,7 +477,7 @@ class PickleStepArgument:
 @dataclass
 class PickleTable:
     rows: list[PickleTableRow]
-    argument_index: Optional[int] = None  # The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+    argument_index: Optional[int] = None  # The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
 
 
 @dataclass
diff --git a/ruby/lib/cucumber/messages/pickle_table.rb b/ruby/lib/cucumber/messages/pickle_table.rb
index 3350c9f55..0bbcfb090 100644
--- a/ruby/lib/cucumber/messages/pickle_table.rb
+++ b/ruby/lib/cucumber/messages/pickle_table.rb
@@ -9,7 +9,7 @@ module Messages
     ##
     class PickleTable < Message
       ##
-      # The index of this argument. The value is 0 if it was declared before the doc string, 1 if it was declared after.
+      # The index of this argument. The value is 1 if it was declared before the doc string, 2 if it was declared after.
       ##
       attr_reader :argument_index