Add a WorkspaceKind property to ProjectContext.

src/LanguageServer/Protocol/Extensions/ProtocolConversions.cs

@@ -827,6 +827,16 @@ public static LSP.VSProjectContext ProjectToProjectContext(Project project)
                 projectContext.Kind = LSP.VSProjectKind.VisualBasic;
             }
 
+            var solution = project.Solution;
+            if (solution.WorkspaceKind == WorkspaceKind.Host)
+            {
+                projectContext.WorkspaceKind = LSP.VSWorkspaceKind.Host;
+            }
+            else if (solution.WorkspaceKind == WorkspaceKind.MiscellaneousFiles)
+            {
+                projectContext.WorkspaceKind = LSP.VSWorkspaceKind.MiscellaneousFiles;
+            }
+
             return projectContext;
         }
 

src/LanguageServer/Protocol/Protocol/Extensions/VSProjectContext.cs

@@ -44,6 +44,16 @@ public VSProjectKind Kind
             set;
         }
 
+        /// <summary>
+        /// Gets or sets the kind of the workspace the project context is associated.
+        /// </summary>
+        [JsonPropertyName("_vs_workspace_kind")]
+        public VSWorkspaceKind WorkspaceKind
+        {
+            get;
+            set;
+        }
+
         public static bool operator ==(VSProjectContext? value1, VSProjectContext? value2)
         {
             if (ReferenceEquals(value1, value2))

src/LanguageServer/Protocol/Protocol/Extensions/VSWorkspaceKind.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Roslyn.LanguageServer.Protocol
+{
+    /// <summary>
+    /// <see cref="VSWorkspaceKind" /> represents the various kinds of known workspaces.
+    /// </summary>
+    internal enum VSWorkspaceKind
+    {
+        /// <summary>
+        /// Host Workspace
+        /// </summary>
+        Host = 1,
+
+        /// <summary>
+        /// Miscellaneous Files Workspace
+        /// </summary>
+        MiscellaneousFiles = 2,
+    }
+}