diff --git a/src/PowerShellEditorServices/Services/TextDocument/Handlers/CodeLensHandlers.cs b/src/PowerShellEditorServices/Services/TextDocument/Handlers/CodeLensHandlers.cs
index 4bcd45a916..961f702caf 100644
--- a/src/PowerShellEditorServices/Services/TextDocument/Handlers/CodeLensHandlers.cs
+++ b/src/PowerShellEditorServices/Services/TextDocument/Handlers/CodeLensHandlers.cs
@@ -15,13 +15,13 @@
 using Microsoft.PowerShell.EditorServices.Services;
 using Microsoft.PowerShell.EditorServices.Services.TextDocument;
 using Microsoft.PowerShell.EditorServices.Utility;
-using OmniSharp.Extensions.LanguageServer.Protocol;
 using OmniSharp.Extensions.LanguageServer.Protocol.Client.Capabilities;
 using OmniSharp.Extensions.LanguageServer.Protocol.Document;
 using OmniSharp.Extensions.LanguageServer.Protocol.Models;
 
 namespace Microsoft.PowerShell.EditorServices.Handlers
 {
+    // TODO: Use ABCs.
     internal class PsesCodeLensHandlers : ICodeLensHandler, ICodeLensResolveHandler
     {
         private readonly Guid _id = new Guid();
@@ -39,13 +39,15 @@ public PsesCodeLensHandlers(ILoggerFactory factory, SymbolsService symbolsServic
             _symbolsService = symbolsService;
         }
 
-        CodeLensRegistrationOptions IRegistration<CodeLensRegistrationOptions>.GetRegistrationOptions()
+        public CodeLensRegistrationOptions GetRegistrationOptions(CodeLensCapability capability, ClientCapabilities clientCapabilities) => new CodeLensRegistrationOptions
         {
-            return new CodeLensRegistrationOptions
-            {
-                DocumentSelector = LspUtils.PowerShellDocumentSelector,
-                ResolveProvider = true
-            };
+            DocumentSelector = LspUtils.PowerShellDocumentSelector,
+            ResolveProvider = true
+        };
+
+        public void SetCapability(CodeLensCapability capability, ClientCapabilities clientCapabilities)
+        {
+            _capability = capability;
         }
 
         public Task<CodeLensContainer> Handle(CodeLensParams request, CancellationToken cancellationToken)
@@ -57,14 +59,6 @@ public Task<CodeLensContainer> Handle(CodeLensParams request, CancellationToken
             return Task.FromResult(new CodeLensContainer(codeLensResults));
         }
 
-        public TextDocumentRegistrationOptions GetRegistrationOptions()
-        {
-            return new TextDocumentRegistrationOptions
-            {
-                DocumentSelector = LspUtils.PowerShellDocumentSelector,
-            };
-        }
-
         public bool CanResolve(CodeLens value)
         {
             CodeLensData codeLensData = value.Data.ToObject<CodeLensData>();
diff --git a/src/PowerShellEditorServices/Services/TextDocument/Handlers/CompletionHandler.cs b/src/PowerShellEditorServices/Services/TextDocument/Handlers/CompletionHandler.cs
index 188a97ce32..de807b8ffe 100644
--- a/src/PowerShellEditorServices/Services/TextDocument/Handlers/CompletionHandler.cs
+++ b/src/PowerShellEditorServices/Services/TextDocument/Handlers/CompletionHandler.cs
@@ -21,6 +21,7 @@
 
 namespace Microsoft.PowerShell.EditorServices.Handlers
 {
+    // TODO: Use ABCs.
     internal class PsesCompletionHandler : ICompletionHandler, ICompletionResolveHandler
     {
         const int DefaultWaitTimeoutMilliseconds = 5000;
@@ -51,17 +52,14 @@ public PsesCompletionHandler(
             _workspaceService = workspaceService;
         }
 
-        public CompletionRegistrationOptions GetRegistrationOptions()
+        protected override CompletionRegistrationOptions CreateRegistrationOptions(CompletionCapability capability, ClientCapabilities clientCapabilities) => new CompletionRegistrationOptions
         {
-            return new CompletionRegistrationOptions
-            {
                 DocumentSelector = LspUtils.PowerShellDocumentSelector,
                 ResolveProvider = true,
                 TriggerCharacters = new[] { ".", "-", ":", "\\" }
-            };
-        }
+        };
 
-        public async Task<CompletionList> Handle(CompletionParams request, CancellationToken cancellationToken)
+        public override async Task<CompletionList> Handle(CompletionParams request, CancellationToken cancellationToken)
         {
             int cursorLine = request.Position.Line + 1;
             int cursorColumn = request.Position.Character + 1;
@@ -117,7 +115,7 @@ public bool CanResolve(CompletionItem value)
         }
 
         // Handler for "completionItem/resolve". In VSCode this is fired when a completion item is highlighted in the completion list.
-        public async Task<CompletionItem> Handle(CompletionItem request, CancellationToken cancellationToken)
+        public async override Task<CompletionItem> Handle(CompletionItem request, CancellationToken cancellationToken)
         {
             // We currently only support this request for anything that returns a CommandInfo: functions, cmdlets, aliases.
             if (request.Kind != CompletionItemKind.Function)
@@ -145,10 +143,11 @@ await CommandHelpers.GetCommandInfoAsync(
 
                 if (commandInfo != null)
                 {
-                    request.Documentation =
-                        await CommandHelpers.GetCommandSynopsisAsync(
-                            commandInfo,
-                            _powerShellContextService).ConfigureAwait(false);
+                    return new CompletionItem()
+                    {
+                        // TODO: Do we need to fill in the rest of the fields?
+                        Documentation = await CommandHelpers.GetCommandSynopsisAsync(commandInfo, _powerShellContextService).ConfigureAwait(false)
+                    };
                 }
 
                 // Send back the updated CompletionItem
diff --git a/src/PowerShellEditorServices/Services/TextDocument/Handlers/FormattingHandlers.cs b/src/PowerShellEditorServices/Services/TextDocument/Handlers/FormattingHandlers.cs
index a229fbea92..0b78e91dce 100644
--- a/src/PowerShellEditorServices/Services/TextDocument/Handlers/FormattingHandlers.cs
+++ b/src/PowerShellEditorServices/Services/TextDocument/Handlers/FormattingHandlers.cs
@@ -17,6 +17,7 @@
 namespace Microsoft.PowerShell.EditorServices.Handlers
 {
     // TODO: Add IDocumentOnTypeFormatHandler to support on-type formatting.
+    // TODO: Use ABCs.
     internal class PsesDocumentFormattingHandlers : IDocumentFormattingHandler, IDocumentRangeFormattingHandler
     {
         private readonly ILogger _logger;