diff --git a/src/Common/OptionBuilder.cs b/src/Common/OptionBuilder.cs
index 08e0938d62..25d33bb959 100644
--- a/src/Common/OptionBuilder.cs
+++ b/src/Common/OptionBuilder.cs
@@ -19,7 +19,7 @@ public static Option CreateOption(string name, Type valueType, string descriptio
         var optionType = typeof(Option<>).MakeGenericType(valueType);
 
 #if NET6_0_OR_GREATER
-            var ctor = (ConstructorInfo)optionType.GetMemberWithSameMetadataDefinitionAs(_ctor);
+        var ctor = (ConstructorInfo)optionType.GetMemberWithSameMetadataDefinitionAs(_ctor);
 #else
         var ctor = optionType.GetConstructor(new[] { typeof(string), typeof(string) });
 #endif
diff --git a/src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt b/src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt
index 13a6b83702..1dc2f6a0b0 100644
--- a/src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt
+++ b/src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt
@@ -1,9 +1,10 @@
 System.CommandLine
   public abstract class Argument : Symbol, System.CommandLine.Binding.IValueDescriptor
     public ArgumentArity Arity { get; set; }
-    public System.Collections.Generic.ICollection<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> Completions { get; }
+    public System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> CompletionSources { get; }
     public System.Boolean HasDefaultValue { get; }
     public System.String HelpName { get; set; }
+    public System.Collections.Generic.List<System.Action<System.CommandLine.Parsing.ArgumentResult>> Validators { get; }
     public System.Type ValueType { get; }
     public System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem> GetCompletions(System.CommandLine.Completions.CompletionContext context)
     public System.Object GetDefaultValue()
@@ -23,10 +24,6 @@ System.CommandLine
     public Argument<T> AcceptLegalFileNamesOnly()
     public Argument<T> AcceptLegalFilePathsOnly()
     public Argument<T> AcceptOnlyFromAmong(System.String[] values)
-    public Argument<T> AddCompletions(System.String[] completions)
-    public Argument<T> AddCompletions(System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.String>> completionsDelegate)
-    public Argument<T> AddCompletions(System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>> completionsDelegate)
-    public Argument<T> AddValidator(System.Action<System.CommandLine.Parsing.ArgumentResult> validate)
     public System.Void SetDefaultValue(T value)
     public System.Void SetDefaultValueFactory(Func<T> defaultValueFactory)
     public System.Void SetDefaultValueFactory(Func<System.CommandLine.Parsing.ArgumentResult,T> defaultValueFactory)
@@ -55,6 +52,7 @@ System.CommandLine
     public System.Collections.Generic.IReadOnlyList<Option> Options { get; }
     public System.Collections.Generic.IReadOnlyList<Command> Subcommands { get; }
     public System.Boolean TreatUnmatchedTokensAsErrors { get; set; }
+    public System.Collections.Generic.List<System.Action<System.CommandLine.Parsing.CommandResult>> Validators { get; }
     public System.Void Add(Option option)
     public System.Void Add(Argument argument)
     public System.Void Add(Command command)
@@ -62,7 +60,6 @@ System.CommandLine
     public System.Void AddCommand(Command command)
     public System.Void AddGlobalOption(Option option)
     public System.Void AddOption(Option option)
-    public System.Void AddValidator(System.Action<System.CommandLine.Parsing.CommandResult> validate)
     public System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem> GetCompletions(System.CommandLine.Completions.CompletionContext context)
     public System.Collections.Generic.IEnumerator<Symbol> GetEnumerator()
   public static class CommandExtensions
@@ -111,8 +108,8 @@ System.CommandLine
     .ctor()
     .ctor(System.String message, System.Exception innerException)
   public static class CompletionSourceExtensions
-    public static System.Void Add(this System.Collections.Generic.ICollection<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.String>> completionsDelegate)
-    public static System.Void Add(this System.Collections.Generic.ICollection<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.String[] completions)
+    public static System.Void Add(this System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.String>> completionsDelegate)
+    public static System.Void Add(this System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> completionSources, System.String[] completions)
   public static class ConsoleExtensions
     public static System.Void Write(this IConsole console, System.String value)
     public static System.Void WriteLine(this IConsole console, System.String value)
@@ -192,7 +189,9 @@ System.CommandLine
     public System.Boolean AllowMultipleArgumentsPerToken { get; set; }
     public System.String ArgumentHelpName { get; set; }
     public ArgumentArity Arity { get; set; }
+    public System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> CompletionSources { get; }
     public System.Boolean IsRequired { get; set; }
+    public System.Collections.Generic.List<System.Action<System.CommandLine.Parsing.OptionResult>> Validators { get; }
     public System.Type ValueType { get; }
     public System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem> GetCompletions(System.CommandLine.Completions.CompletionContext context)
     public ParseResult Parse(System.String commandLine)
@@ -207,10 +206,6 @@ System.CommandLine
     public Option<T> AcceptLegalFileNamesOnly()
     public Option<T> AcceptLegalFilePathsOnly()
     public Option<T> AcceptOnlyFromAmong(System.String[] values)
-    public Option<T> AddCompletions(System.String[] completions)
-    public Option<T> AddCompletions(System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.String>> completionsDelegate)
-    public Option<T> AddCompletions(System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>> completionsDelegate)
-    public Option<T> AddValidator(System.Action<System.CommandLine.Parsing.OptionResult> validate)
     public System.Void SetDefaultValue(T value)
     public System.Void SetDefaultValueFactory(Func<T> defaultValueFactory)
   public static class OptionValidation
diff --git a/src/System.CommandLine.Benchmarks/CommandLine/Perf_Parser_Directives_Suggest.cs b/src/System.CommandLine.Benchmarks/CommandLine/Perf_Parser_Directives_Suggest.cs
index 0b0477754d..0df2796867 100644
--- a/src/System.CommandLine.Benchmarks/CommandLine/Perf_Parser_Directives_Suggest.cs
+++ b/src/System.CommandLine.Benchmarks/CommandLine/Perf_Parser_Directives_Suggest.cs
@@ -22,10 +22,16 @@ public void Setup()
         {
             _nullConsole = new NullConsole();
 
+            Option<string> fruitOption = new("--fruit");
+            fruitOption.CompletionSources.Add("apple", "banana", "cherry");
+
+            Option<string> vegetableOption = new("--vegetable");
+            vegetableOption.CompletionSources.Add("asparagus", "broccoli", "carrot");
+
             var eatCommand = new Command("eat")
             {
-                new Option<string>("--fruit").AddCompletions("apple", "banana", "cherry"),
-                new Option<string>("--vegetable").AddCompletions("asparagus", "broccoli", "carrot")
+                fruitOption,
+                vegetableOption
             };
 
             _testParser = new CommandLineBuilder(eatCommand)
diff --git a/src/System.CommandLine.Benchmarks/CommandLine/Perf_Suggestions.cs b/src/System.CommandLine.Benchmarks/CommandLine/Perf_Suggestions.cs
index ab680141a2..cd84312277 100644
--- a/src/System.CommandLine.Benchmarks/CommandLine/Perf_Suggestions.cs
+++ b/src/System.CommandLine.Benchmarks/CommandLine/Perf_Suggestions.cs
@@ -15,7 +15,7 @@ namespace System.CommandLine.Benchmarks.CommandLine
     [BenchmarkCategory(Categories.CommandLine)]
     public class Perf_Suggestions
     {
-        private Symbol _testSymbol;
+        private Option _testSymbol;
         private ParseResult _testParseResult;
 
         /// <remarks>
@@ -37,8 +37,8 @@ private IEnumerable<Option> GenerateOptionsArray(int count)
         [GlobalSetup(Target = nameof(SuggestionsFromSymbol))]
         public void Setup_FromSymbol()
         {
-            _testSymbol = new Option<string>("--hello")
-                .AddCompletions(GenerateSuggestionsArray(TestSuggestionsCount));
+            _testSymbol = new Option<string>("--hello");
+            _testSymbol.CompletionSources.Add(GenerateSuggestionsArray(TestSuggestionsCount));
         }
 
         [Benchmark]
diff --git a/src/System.CommandLine.Tests/ArgumentTests.cs b/src/System.CommandLine.Tests/ArgumentTests.cs
index d9d8b88ab4..f674aa8a22 100644
--- a/src/System.CommandLine.Tests/ArgumentTests.cs
+++ b/src/System.CommandLine.Tests/ArgumentTests.cs
@@ -789,10 +789,6 @@ public void Argument_of_T_fluent_APIs_return_Argument_of_T()
         {
             Argument<string> argument = new Argument<string>("--path")
                 .AcceptOnlyFromAmong("text")
-                .AddCompletions("test")
-                .AddCompletions(ctx => Array.Empty<string>())
-                .AddCompletions(ctx => Array.Empty<CompletionItem>())
-                .AddValidator(_ => { })
                 .AcceptLegalFileNamesOnly()
                 .AcceptLegalFilePathsOnly();
 
diff --git a/src/System.CommandLine.Tests/CompletionTests.cs b/src/System.CommandLine.Tests/CompletionTests.cs
index 80f2f576d3..cad2213ceb 100644
--- a/src/System.CommandLine.Tests/CompletionTests.cs
+++ b/src/System.CommandLine.Tests/CompletionTests.cs
@@ -25,8 +25,8 @@ public CompletionTests(ITestOutputHelper output)
         [Fact]
         public void Option_GetCompletions_returns_argument_completions_if_configured()
         {
-            var option = new Option<string>("--hello")
-                .AddCompletions("one", "two", "three");
+            var option = new Option<string>("--hello");
+            option.CompletionSources.Add("one", "two", "three");
 
             var completions = option.GetCompletions(CompletionContext.Empty);
 
@@ -122,7 +122,7 @@ public void Command_GetCompletions_returns_available_subcommands_and_option_alia
                 new Argument<string[]>
                 {
                     Arity = ArgumentArity.OneOrMore,
-                    Completions = { "command-argument" }
+                    CompletionSources = { "command-argument" }
                 }
             };
 
@@ -211,17 +211,19 @@ public void When_an_option_has_a_default_value_it_will_still_be_suggested()
         public void Command_GetCompletions_can_access_ParseResult()
         {
             var originOption = new Option<string>("--origin");
+            var cloneOption = new Option<string>("--clone");
+
+            cloneOption.CompletionSources.Add(ctx =>
+            {
+                var opt1Value = ctx.ParseResult.GetValue(originOption);
+                return !string.IsNullOrWhiteSpace(opt1Value) ? new[] { opt1Value } : Array.Empty<string>();
+            });
 
             var parser = new Parser(
                 new RootCommand
                 {
                     originOption,
-                    new Option<string>("--clone")
-                        .AddCompletions(ctx =>
-                        {
-                            var opt1Value = ctx.ParseResult.GetValue(originOption);
-                            return !string.IsNullOrWhiteSpace(opt1Value) ? new[] { opt1Value } : Array.Empty<string>();
-                        })
+                    cloneOption
                 });
 
             var result = parser.Parse("--origin test --clone ");
@@ -579,10 +581,12 @@ public void Option_GetCompletions_can_be_based_on_the_proximate_option_and_parti
         [Fact]
         public void Completions_can_be_provided_in_the_absence_of_validation()
         {
+            Option<string> option = new ("-t");
+            option.CompletionSources.Add("vegetable", "mineral", "animal");
+
             var command = new Command("the-command")
                 {
-                    new Option<string>("-t")
-                        .AddCompletions("vegetable", "mineral", "animal")
+                    option
                 };
 
             command.Parse("the-command -t m")
@@ -607,7 +611,7 @@ public void Command_argument_completions_can_be_provided_using_a_delegate()
                 {
                     new Argument<string>
                         {
-                            Completions = { _ => new[] { "vegetable", "mineral", "animal" } }
+                            CompletionSources = { _ => new[] { "vegetable", "mineral", "animal" } }
                         }
                 }
             };
@@ -622,10 +626,12 @@ public void Command_argument_completions_can_be_provided_using_a_delegate()
         [Fact]
         public void Option_argument_completions_can_be_provided_using_a_delegate()
         {
+            var option = new Option<string>("-x");
+            option.CompletionSources.Add(_ => new[] { "vegetable", "mineral", "animal" });
+
             var command = new Command("the-command")
             {
-                new Option<string>("-x")
-                    .AddCompletions(_ => new [] { "vegetable", "mineral", "animal" })
+                option
             };
 
             var parseResult = command.Parse("the-command -x m");
@@ -851,8 +857,8 @@ public void It_can_provide_completions_within_quotes(string commandLine, int pos
                 "\"nuget:Microsoft.DotNet.Interactive\""
             };
 
-            var argument = new Argument<string>()
-                .AddCompletions(expectedSuggestions);
+            var argument = new Argument<string>();
+            argument.CompletionSources.Add(expectedSuggestions);
 
             var r = new Command("#r")
             {
@@ -873,8 +879,8 @@ public void It_can_provide_completions_within_quotes(string commandLine, int pos
         public void Default_completions_can_be_cleared_and_replaced()
         {
             var argument = new Argument<DayOfWeek>();
-            argument.Completions.Clear();
-            argument.Completions.Add(new[] { "mon", "tues", "wed", "thur", "fri", "sat", "sun" });
+            argument.CompletionSources.Clear();
+            argument.CompletionSources.Add(new[] { "mon", "tues", "wed", "thur", "fri", "sat", "sun" });
             var command = new Command("the-command")
             {
                 argument
@@ -895,7 +901,7 @@ public void Default_completions_can_be_appended_to()
             {
                 new Argument<DayOfWeek>
                 {
-                    Completions = { "mon", "tues", "wed", "thur", "fri", "sat", "sun" }
+                    CompletionSources = { "mon", "tues", "wed", "thur", "fri", "sat", "sun" }
                 }
             };
 
diff --git a/src/System.CommandLine.Tests/OptionTests.cs b/src/System.CommandLine.Tests/OptionTests.cs
index 56b4a7752c..24bf89f39a 100644
--- a/src/System.CommandLine.Tests/OptionTests.cs
+++ b/src/System.CommandLine.Tests/OptionTests.cs
@@ -286,7 +286,7 @@ public void Option_T_default_value_factory_can_be_set_after_instantiation()
         public void Option_T_default_value_is_validated()
         {
             var option = new Option<int>("-x", () => 123);
-            option.AddValidator(symbol =>
+            option.Validators.Add(symbol =>
                                     symbol.ErrorMessage = symbol.Tokens
                                                                 .Select(t => t.Value)
                                                                 .Where(v => v == "123")
@@ -374,10 +374,6 @@ public void Option_of_T_fluent_APIs_return_Option_of_T()
         {
             Option<string> option = new Option<string>("--path")
                 .AcceptOnlyFromAmong("text")
-                .AddCompletions("test")
-                .AddCompletions(ctx => Array.Empty<string>())
-                .AddCompletions(ctx => Array.Empty<CompletionItem>())
-                .AddValidator(_ => { })
                 .AcceptLegalFileNamesOnly()
                 .AcceptLegalFilePathsOnly();
 
diff --git a/src/System.CommandLine.Tests/ParsingValidationTests.cs b/src/System.CommandLine.Tests/ParsingValidationTests.cs
index 2d66518ac3..bb922c9c19 100644
--- a/src/System.CommandLine.Tests/ParsingValidationTests.cs
+++ b/src/System.CommandLine.Tests/ParsingValidationTests.cs
@@ -275,7 +275,7 @@ public void A_custom_validator_can_be_added_to_a_command()
                 new Option<bool>("--two")
             };
 
-            command.AddValidator(commandResult =>
+            command.Validators.Add(commandResult =>
             {
                 if (commandResult.Children.Any(sr => sr.Symbol is IdentifierSymbol id && id.HasAlias("--one")) &&
                     commandResult.Children.Any(sr => sr.Symbol is IdentifierSymbol id && id.HasAlias("--two")))
@@ -300,7 +300,7 @@ public void A_custom_validator_can_be_added_to_an_option()
         {
             var option = new Option<int>("-x");
 
-            option.AddValidator(r =>
+            option.Validators.Add(r =>
             {
                 var value = r.GetValueOrDefault<int>();
 
@@ -327,7 +327,7 @@ public void A_custom_validator_can_be_added_to_an_argument()
         {
             var argument = new Argument<int>("x");
 
-            argument.AddValidator(r =>
+            argument.Validators.Add(r =>
             {
                 var value = r.GetValueOrDefault<int>();
 
@@ -359,13 +359,13 @@ public void All_custom_validators_are_called(string commandLine)
             var argumentValidatorWasCalled = false;
 
             var option = new Option<string>("-o");
-            option.AddValidator(_ =>
+            option.Validators.Add(_ =>
             {
                 optionValidatorWasCalled = true;
             });
 
             var argument = new Argument<string>("the-arg");
-            argument.AddValidator(_ =>
+            argument.Validators.Add(_ =>
             {
                 argumentValidatorWasCalled = true;
             });
@@ -375,7 +375,7 @@ public void All_custom_validators_are_called(string commandLine)
                 option,
                 argument
             };
-            rootCommand.AddValidator(_ =>
+            rootCommand.Validators.Add(_ =>
             {
                 commandValidatorWasCalled = true;
             });
@@ -393,7 +393,7 @@ public void All_custom_validators_are_called(string commandLine)
         public void Validators_on_global_options_are_executed_when_invoking_a_subcommand(string commandLine)
         {
             var option = new Option<FileInfo>("--file");
-            option.AddValidator(r =>
+            option.Validators.Add(r =>
             {
                 r.ErrorMessage = "Invoked validator";
             });
@@ -430,7 +430,7 @@ public async Task A_custom_validator_added_to_a_global_option_is_checked(string
             var handlerWasCalled = false;
 
             var globalOption = new Option<int>("--value");
-            globalOption.AddValidator(r => r.ErrorMessage = "oops!");
+            globalOption.Validators.Add(r => r.ErrorMessage = "oops!");
 
             var grandchildCommand = new Command("grandchild");
 
@@ -460,7 +460,7 @@ public void Custom_validator_error_messages_are_not_repeated()
         {
             var errorMessage = "that's not right...";
             var argument = new Argument<string>();
-            argument.AddValidator(r => r.ErrorMessage = errorMessage);
+            argument.Validators.Add(r => r.ErrorMessage = errorMessage);
 
             var cmd = new Command("get")
             {
@@ -481,7 +481,7 @@ public void The_parsed_value_of_an_argument_is_available_within_a_validator()
         {
             var argument = new Argument<int>();
             var errorMessage = "The value of option '-x' must be between 1 and 100.";
-            argument.AddValidator(result =>
+            argument.Validators.Add(result =>
             {
                 var value = result.GetValue(argument);
 
@@ -505,7 +505,7 @@ public void The_parsed_value_of_an_option_is_available_within_a_validator()
         {
             var option = new Option<int>("-x");
             var errorMessage = "The value of option '-x' must be between 1 and 100.";
-            option.AddValidator(result =>
+            option.Validators.Add(result =>
             {
                 var value = result.GetValue(option);
 
@@ -1121,8 +1121,8 @@ public void Arity_failures_are_not_reported_for_both_an_argument_and_its_parent_
         public void Multiple_validators_on_the_same_command_do_not_report_duplicate_errors()
         {
             var command = new RootCommand();
-            command.AddValidator(result => result.ErrorMessage = "Wrong");
-            command.AddValidator(_ => { });
+            command.Validators.Add(result => result.ErrorMessage = "Wrong");
+            command.Validators.Add(_ => { });
 
             var parseResult = command.Parse("");
 
@@ -1139,8 +1139,8 @@ public void Multiple_validators_on_the_same_command_do_not_report_duplicate_erro
         public void Multiple_validators_on_the_same_option_do_not_report_duplicate_errors()
         {
             var option = new Option<string>("-x");
-            option.AddValidator(result => result.ErrorMessage = "Wrong");
-            option.AddValidator(_ => { });
+            option.Validators.Add(result => result.ErrorMessage = "Wrong");
+            option.Validators.Add(_ => { });
 
             var command = new RootCommand
             {
@@ -1162,8 +1162,8 @@ public void Multiple_validators_on_the_same_option_do_not_report_duplicate_error
         public void Multiple_validators_on_the_same_argument_do_not_report_duplicate_errors()
         {
             var argument = new Argument<string>();
-            argument.AddValidator(result => result.ErrorMessage = "Wrong");
-            argument.AddValidator(_ => { });
+            argument.Validators.Add(result => result.ErrorMessage = "Wrong");
+            argument.Validators.Add(_ => { });
 
             var command = new RootCommand
             {
@@ -1185,7 +1185,7 @@ public void Multiple_validators_on_the_same_argument_do_not_report_duplicate_err
         internal void When_there_is_an_arity_error_then_further_errors_are_not_reported()
         {
             var option = new Option<string>("-o");
-            option.AddValidator(result =>
+            option.Validators.Add(result =>
             {
                 result.ErrorMessage = "OOPS";
             }); //all good;
diff --git a/src/System.CommandLine.Tests/SuggestDirectiveTests.cs b/src/System.CommandLine.Tests/SuggestDirectiveTests.cs
index 09d9b529f4..ac1e03efd1 100644
--- a/src/System.CommandLine.Tests/SuggestDirectiveTests.cs
+++ b/src/System.CommandLine.Tests/SuggestDirectiveTests.cs
@@ -20,11 +20,11 @@ public class SuggestDirectiveTests
 
         public SuggestDirectiveTests()
         {
-            _fruitOption = new Option<string>("--fruit")
-                .AddCompletions("apple", "banana", "cherry");
+            _fruitOption = new Option<string>("--fruit");
+            _fruitOption.CompletionSources.Add("apple", "banana", "cherry");
 
-            _vegetableOption = new Option<string>("--vegetable")
-                .AddCompletions(_ => new[] { "asparagus", "broccoli", "carrot" });
+            _vegetableOption = new Option<string>("--vegetable");
+            _vegetableOption.CompletionSources.Add(_ => new[] { "asparagus", "broccoli", "carrot" });
 
             _eatCommand = new Command("eat")
             {
diff --git a/src/System.CommandLine/Argument.cs b/src/System.CommandLine/Argument.cs
index 9467e4400d..2ebd5e1c44 100644
--- a/src/System.CommandLine/Argument.cs
+++ b/src/System.CommandLine/Argument.cs
@@ -16,7 +16,7 @@ public abstract class Argument : Symbol, IValueDescriptor
     {
         private ArgumentArity _arity;
         private TryConvertArgument? _convertArguments;
-        private List<Func<CompletionContext, IEnumerable<CompletionItem>>>? _completions = null;
+        private List<Func<CompletionContext, IEnumerable<CompletionItem>>>? _completionSources = null;
         private List<Action<ArgumentResult>>? _validators = null;
 
         /// <summary>
@@ -71,10 +71,10 @@ internal TryConvertArgument? ConvertArguments
         }
 
         /// <summary>
-        /// Gets the collection of completion sources for the argument.
+        /// Gets the list of completion sources for the argument.
         /// </summary>
-        public ICollection<Func<CompletionContext, IEnumerable<CompletionItem>>> Completions =>
-            _completions ??= new ()
+        public List<Func<CompletionContext, IEnumerable<CompletionItem>>> CompletionSources =>
+            _completionSources ??= new ()
             {
                 CompletionSource.ForType(ValueType)
             };
@@ -103,7 +103,11 @@ private protected override string DefaultName
             }
         }
 
-        internal List<Action<ArgumentResult>> Validators => _validators ??= new ();
+        /// <summary>
+        /// Provides a list of argument validators. Validators can be used
+        /// to provide custom errors based on user input.
+        /// </summary>
+        public List<Action<ArgumentResult>> Validators => _validators ??= new ();
 
         /// <summary>
         /// Gets the default value for the argument.
@@ -136,7 +140,7 @@ internal void AddAllowedValues(IReadOnlyList<string> values)
         /// <inheritdoc />
         public override IEnumerable<CompletionItem> GetCompletions(CompletionContext context)
         {
-            return Completions
+            return CompletionSources
                    .SelectMany(source => source.Invoke(context))
                    .Distinct()
                    .OrderBy(c => c.SortText, StringComparer.OrdinalIgnoreCase);
diff --git a/src/System.CommandLine/ArgumentValidation.cs b/src/System.CommandLine/ArgumentValidation.cs
index 37282c871a..a4cc6cc3d1 100644
--- a/src/System.CommandLine/ArgumentValidation.cs
+++ b/src/System.CommandLine/ArgumentValidation.cs
@@ -18,7 +18,7 @@ public static class ArgumentValidation
         /// <returns>The configured argument.</returns>
         public static Argument<FileInfo> AcceptExistingOnly(this Argument<FileInfo> argument)
         {
-            argument.AddValidator(Validate.FileExists);
+            argument.Validators.Add(Validate.FileExists);
             return argument;
         }
 
@@ -29,7 +29,7 @@ public static Argument<FileInfo> AcceptExistingOnly(this Argument<FileInfo> argu
         /// <returns>The configured argument.</returns>
         public static Argument<DirectoryInfo> AcceptExistingOnly(this Argument<DirectoryInfo> argument)
         {
-            argument.AddValidator(Validate.DirectoryExists);
+            argument.Validators.Add(Validate.DirectoryExists);
             return argument;
         }
 
@@ -40,7 +40,7 @@ public static Argument<DirectoryInfo> AcceptExistingOnly(this Argument<Directory
         /// <returns>The configured argument.</returns>
         public static Argument<FileSystemInfo> AcceptExistingOnly(this Argument<FileSystemInfo> argument)
         {
-            argument.AddValidator(Validate.FileOrDirectoryExists);
+            argument.Validators.Add(Validate.FileOrDirectoryExists);
             return argument;
         }
 
@@ -54,15 +54,15 @@ public static Argument<T> AcceptExistingOnly<T>(this Argument<T> argument)
         {
             if (typeof(IEnumerable<FileInfo>).IsAssignableFrom(typeof(T)))
             {
-                argument.AddValidator(Validate.FileExists);
+                argument.Validators.Add(Validate.FileExists);
             }
             else if (typeof(IEnumerable<DirectoryInfo>).IsAssignableFrom(typeof(T)))
             {
-                argument.AddValidator(Validate.DirectoryExists);
+                argument.Validators.Add(Validate.DirectoryExists);
             }
             else
             {
-                argument.AddValidator(Validate.FileOrDirectoryExists);
+                argument.Validators.Add(Validate.FileOrDirectoryExists);
             }
 
             return argument;
diff --git a/src/System.CommandLine/Argument{T}.cs b/src/System.CommandLine/Argument{T}.cs
index 06cf7d3696..dea4e2fffc 100644
--- a/src/System.CommandLine/Argument{T}.cs
+++ b/src/System.CommandLine/Argument{T}.cs
@@ -172,50 +172,6 @@ public void SetDefaultValueFactory(Func<ArgumentResult, T> defaultValueFactory)
             return _defaultValueFactory.Invoke(argumentResult);
         }
 
-        /// <summary>
-        /// Adds completions for the argument.
-        /// </summary>
-        /// <param name="completions">The completions to add.</param>
-        /// <returns>The configured argument.</returns>
-        public Argument<T> AddCompletions(params string[] completions)
-        {
-            Completions.Add(completions);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds completions for the argument.
-        /// </summary>
-        /// <param name="completionsDelegate">A function that will be called to provide completions.</param>
-        /// <returns>The option being extended.</returns>
-        public Argument<T> AddCompletions(Func<CompletionContext, IEnumerable<string>> completionsDelegate)
-        {
-            Completions.Add(completionsDelegate);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds completions for the argument.
-        /// </summary>
-        /// <param name="completionsDelegate">A function that will be called to provide completions.</param>
-        /// <returns>The configured argument.</returns>
-        public Argument<T> AddCompletions(Func<CompletionContext, IEnumerable<CompletionItem>> completionsDelegate)
-        {
-            Completions.Add(completionsDelegate);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds a custom validator to the argument. Validators can be used
-        /// to provide custom errors based on user input.
-        /// </summary>
-        /// <param name="validate">The action to validate the parsed argument.</param>
-        public Argument<T> AddValidator(Action<ArgumentResult> validate)
-        {
-            Validators.Add(validate);
-            return this;
-        }
-
         /// <summary>
         /// Configures the argument to accept only the specified values, and to suggest them as command line completions.
         /// </summary>
@@ -225,8 +181,8 @@ public Argument<T> AcceptOnlyFromAmong(params string[] values)
         {
             AllowedValues?.Clear();
             AddAllowedValues(values);
-            Completions.Clear();
-            Completions.Add(values);
+            CompletionSources.Clear();
+            CompletionSources.Add(values);
 
             return this;
         }
@@ -239,7 +195,7 @@ public Argument<T> AcceptLegalFilePathsOnly()
         {
             var invalidPathChars = Path.GetInvalidPathChars();
 
-            AddValidator(result =>
+            Validators.Add(result =>
             {
                 for (var i = 0; i < result.Tokens.Count; i++)
                 {
@@ -268,7 +224,7 @@ public Argument<T> AcceptLegalFileNamesOnly()
         {
             var invalidFileNameChars = Path.GetInvalidFileNameChars();
 
-            AddValidator(result =>
+            Validators.Add(result =>
             {
                 for (var i = 0; i < result.Tokens.Count; i++)
                 {
diff --git a/src/System.CommandLine/Command.cs b/src/System.CommandLine/Command.cs
index 1f8d037b3e..d4d16d9f60 100644
--- a/src/System.CommandLine/Command.cs
+++ b/src/System.CommandLine/Command.cs
@@ -68,10 +68,13 @@ public IEnumerable<Symbol> Children
         /// </summary>
         public IReadOnlyList<Command> Subcommands => _subcommands is not null ? _subcommands : Array.Empty<Command>();
 
-        internal IReadOnlyList<Action<CommandResult>> Validators
-            => _validators is not null ? _validators : Array.Empty<Action<CommandResult>>();
+        /// <summary>
+        /// Validators to the command. Validators can be used
+        /// to create custom validation logic.
+        /// </summary>
+        public List<Action<CommandResult>> Validators => _validators ??= new ();
 
-        internal bool HasValidators => _validators is not null; // initialized by Add method, so when it's not null the Count is always > 0
+        internal bool HasValidators => _validators is not null && _validators.Count > 0;
 
         /// <summary>
         /// Adds an <see cref="Argument"/> to the command.
@@ -136,13 +139,6 @@ public void AddGlobalOption(Option option)
 
         private protected override string DefaultName => throw new NotImplementedException();
 
-        /// <summary>
-        /// Adds a custom validator to the command. Validators can be used
-        /// to create custom validation logic.
-        /// </summary>
-        /// <param name="validate">The action to validate the symbols during parsing.</param>
-        public void AddValidator(Action<CommandResult> validate) => (_validators ??= new()).Add(validate);
-
         /// <summary>
         /// Gets or sets a value that indicates whether unmatched tokens should be treated as errors. For example,
         /// if set to <see langword="true"/> and an extra command or argument is provided, validation will fail.
diff --git a/src/System.CommandLine/CompletionSourceExtensions.cs b/src/System.CommandLine/CompletionSourceExtensions.cs
index bfe34fd2a4..8c775508b3 100644
--- a/src/System.CommandLine/CompletionSourceExtensions.cs
+++ b/src/System.CommandLine/CompletionSourceExtensions.cs
@@ -18,7 +18,7 @@ public static class CompletionSourceExtensions
         /// <param name="completionSources">The list of completion sources to add to.</param>
         /// <param name="completionsDelegate">The delegate to be called when calculating completions.</param>
         public static void Add(
-            this ICollection<Func<CompletionContext, IEnumerable<CompletionItem>>> completionSources,
+            this List<Func<CompletionContext, IEnumerable<CompletionItem>>> completionSources,
             Func<CompletionContext, IEnumerable<string>> completionsDelegate)
         {
             if (completionSources is null)
@@ -40,7 +40,7 @@ public static void Add(
         /// <param name="completionSources">The list of completion sources to add to.</param>
         /// <param name="completions">A list of strings to be suggested for command line completions.</param>
         public static void Add(
-            this ICollection<Func<CompletionContext, IEnumerable<CompletionItem>>> completionSources,
+            this List<Func<CompletionContext, IEnumerable<CompletionItem>>> completionSources,
             params string[] completions)
         {
             if (completionSources is null)
diff --git a/src/System.CommandLine/Help/VersionOption.cs b/src/System.CommandLine/Help/VersionOption.cs
index ab906b8d01..800cbfb12e 100644
--- a/src/System.CommandLine/Help/VersionOption.cs
+++ b/src/System.CommandLine/Help/VersionOption.cs
@@ -31,7 +31,7 @@ public VersionOption(string[] aliases, CommandLineBuilder builder) : base(aliase
 
         private void AddValidators()
         {
-            AddValidator(result =>
+            Validators.Add(result =>
             {
                 if (result.Parent is { } parent &&
                     parent.Children.Where(r => r.Symbol is not VersionOption)
diff --git a/src/System.CommandLine/Option.cs b/src/System.CommandLine/Option.cs
index 1a9ad0f7c8..02bb41e26b 100644
--- a/src/System.CommandLine/Option.cs
+++ b/src/System.CommandLine/Option.cs
@@ -79,10 +79,18 @@ public ArgumentArity Arity
 
         internal bool DisallowBinding { get; init; }
 
-        internal List<Action<OptionResult>> Validators => _validators ??= new();
+        /// <summary>
+        /// Validators that will be called when the option is matched by the parser.
+        /// </summary>
+        public List<Action<OptionResult>> Validators => _validators ??= new();
 
         internal bool HasValidators => _validators is not null && _validators.Count > 0;
 
+        /// <summary>
+        /// Gets the list of completion sources for the option.
+        /// </summary>
+        public List<Func<CompletionContext, IEnumerable<CompletionItem>>> CompletionSources => Argument.CompletionSources;
+
         /// <summary>
         /// Gets a value that indicates whether multiple argument tokens are allowed for each option identifier token.
         /// </summary>
diff --git a/src/System.CommandLine/Option{T}.cs b/src/System.CommandLine/Option{T}.cs
index d3ff98acdd..1f75694a78 100644
--- a/src/System.CommandLine/Option{T}.cs
+++ b/src/System.CommandLine/Option{T}.cs
@@ -1,9 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System.Collections.Generic;
 using System.CommandLine.Binding;
-using System.CommandLine.Completions;
 using System.CommandLine.Parsing;
 
 namespace System.CommandLine
@@ -113,49 +111,6 @@ public Option<T> AcceptOnlyFromAmong(params string[] values)
             return this;
         }
 
-        /// <summary>
-        /// Adds completions for the option.
-        /// </summary>
-        /// <param name="completions">The completions to add.</param>
-        /// <returns>The configured option.</returns>
-        public Option<T> AddCompletions(params string[] completions)
-        {
-            _argument.Completions.Add(completions);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds completions for the option.
-        /// </summary>
-        /// <param name="completionsDelegate">A function that will be called to provide completions.</param>
-        /// <returns>The configured option.</returns>
-        public Option<T> AddCompletions(Func<CompletionContext, IEnumerable<string>> completionsDelegate)
-        {
-            _argument.Completions.Add(completionsDelegate);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds completions for the option.
-        /// </summary>
-        /// <param name="completionsDelegate">A function that will be called to provide completions.</param>
-        /// <returns>The configured option.</returns>
-        public Option<T> AddCompletions(Func<CompletionContext, IEnumerable<CompletionItem>> completionsDelegate)
-        {
-            _argument.Completions.Add(completionsDelegate);
-            return this;
-        }
-
-        /// <summary>
-        /// Adds a validator that will be called when the option is matched by the parser.
-        /// </summary>
-        /// <param name="validate">An action used to validate the <see cref="OptionResult"/> produced during parsing.</param>
-        public Option<T> AddValidator(Action<OptionResult> validate)
-        {
-            Validators.Add(validate);
-            return this;
-        }
-
         /// <summary>
         /// Configures the option to accept only values representing legal file paths.
         /// </summary>