diff --git a/XSDVisualiser.Desktop/ViewModels/MainWindowViewModel.cs b/XSDVisualiser.Desktop/ViewModels/MainWindowViewModel.cs
index 7b24482..93d28b2 100644
--- a/XSDVisualiser.Desktop/ViewModels/MainWindowViewModel.cs
+++ b/XSDVisualiser.Desktop/ViewModels/MainWindowViewModel.cs
@@ -4,6 +4,10 @@ using XSDVisualiser.Core;
 
 namespace XSDVisualiser.Desktop.ViewModels;
 
+/// <summary>
+/// View model exposing the parsed schema for binding in the main window.
+/// Provides selection state and information about the currently loaded XSD file.
+/// </summary>
 public class MainWindowViewModel(SchemaModel model) : INotifyPropertyChanged
 {
     private string? _currentFilePath;
@@ -11,6 +15,10 @@ public class MainWindowViewModel(SchemaModel model) : INotifyPropertyChanged
     private SchemaNode? _selectedNode;
     private SchemaNode? _selectedRootElement;
 
+    /// <summary>
+    /// Parsed schema model currently displayed by the UI.
+    /// Setting this property updates dependent properties and notifies bindings.
+    /// </summary>
     public SchemaModel Model
     {
         get => _model;
@@ -24,8 +32,14 @@ public class MainWindowViewModel(SchemaModel model) : INotifyPropertyChanged
         }
     }
 
+    /// <summary>
+    /// All global elements defined in the loaded schema.
+    /// </summary>
     public IEnumerable<SchemaNode> RootElements => _model?.RootElements ?? Enumerable.Empty<SchemaNode>();
 
+    /// <summary>
+    /// If set, filters the view to show only this root element and its subtree.
+    /// </summary>
     public SchemaNode? SelectedRootElement
     {
         get => _selectedRootElement;
diff --git a/XSDVisualiser.Desktop/Views/LeftTreeView.axaml.cs b/XSDVisualiser.Desktop/Views/LeftTreeView.axaml.cs
index b24ee8b..58f71cd 100644
--- a/XSDVisualiser.Desktop/Views/LeftTreeView.axaml.cs
+++ b/XSDVisualiser.Desktop/Views/LeftTreeView.axaml.cs
@@ -15,6 +15,10 @@ using XSDVisualiser.Desktop.ViewModels;
 
 namespace XSDVisualiser.Desktop.Views;
 
+/// <summary>
+///     Left-side tree view control that displays parsed XSD schema nodes and provides actions
+///     such as copy-as-TSV, validate against XML, and export sample XML.
+/// </summary>
 public partial class LeftTreeView : UserControl
 {
     public LeftTreeView()
@@ -24,7 +28,6 @@ public partial class LeftTreeView : UserControl
 
     private async void OnCopyAsTsvClick(object? sender, RoutedEventArgs e)
     {
-        // Determine the node from the menu item's DataContext
         var node = (sender as MenuItem)?.DataContext as SchemaNode;
         if (node == null)
             node =
@@ -40,7 +43,6 @@ public partial class LeftTreeView : UserControl
 
     private async void OnValidateAgainstXmlClick(object? sender, RoutedEventArgs e)
     {
-        // Resolve node from context
         var node = (sender as MenuItem)?.DataContext as SchemaNode;
         if (node == null)
             node = (sender as Control)?.GetVisualAncestors().OfType<Control>().FirstOrDefault()?.DataContext as SchemaNode;
@@ -96,7 +98,6 @@ public partial class LeftTreeView : UserControl
     private static string BuildTsv(SchemaNode root)
     {
         var sb = new StringBuilder();
-        // Header
         sb.AppendLine(
             "Depth\tPath\tName\tNamespace\tTypeName\tBuiltInType\tMinOccurs\tMaxOccurs\tContentModel\tConstraints\tIsNillable");
         var initialPath = root.Name ?? string.Empty;
@@ -146,7 +147,6 @@ public partial class LeftTreeView : UserControl
 
     private static async Task<string?> TryGetLocalPathAsync(IStorageFile file)
     {
-        // Avalonia provides TryGetLocalPath extension for local files; otherwise, we can't access it via System.IO API.
         return file.TryGetLocalPath();
     }
 
@@ -183,10 +183,8 @@ public partial class LeftTreeView : UserControl
             }
         };
 
-        // Compose content
         if (dialog.Content is Grid grid)
         {
-            // Use a read-only TextBox so users can select text easily
             var textBox = new TextBox
             {
                 Text = text,
@@ -198,7 +196,6 @@ public partial class LeftTreeView : UserControl
 
             var scroller = new ScrollViewer { Content = textBox };
 
-            // Copy button
             var copyButton = new Button
             {
                 Content = "Copy",
@@ -212,7 +209,6 @@ public partial class LeftTreeView : UserControl
                 if (topLevel?.Clipboard != null)
                 {
                     await topLevel.Clipboard.SetTextAsync(text);
-                    // Provide lightweight feedback by changing content briefly
                     if (copyButton.Content is string)
                         copyButton.Content = "Copied";
                     await Task.Delay(1000);
diff --git a/XSDVisualiser/Models/AttributeInfo.cs b/XSDVisualiser/Models/AttributeInfo.cs
index e377aae..991bc12 100644
--- a/XSDVisualiser/Models/AttributeInfo.cs
+++ b/XSDVisualiser/Models/AttributeInfo.cs
@@ -7,15 +7,33 @@ namespace XSDVisualiser.Core;
 /// </summary>
 public class AttributeInfo
 {
+    /// <summary>
+    ///     Local name of the attribute.
+    /// </summary>
     [XmlAttribute] public string? Name { get; set; }
 
+    /// <summary>
+    ///     Namespace URI of the attribute, if any.
+    /// </summary>
     [XmlAttribute] public string? Namespace { get; set; }
 
-    [XmlAttribute] public string? Use { get; set; } // optional | required | prohibited
+    /// <summary>
+    ///     Usage of the attribute: optional | required | prohibited.
+    /// </summary>
+    [XmlAttribute] public string? Use { get; set; }
 
+    /// <summary>
+    ///     The qualified type name if the attribute has a named type.
+    /// </summary>
     [XmlAttribute] public string? TypeName { get; set; }
 
+    /// <summary>
+    ///     Built-in XML Schema type code name when applicable.
+    /// </summary>
     [XmlAttribute] public string? BuiltInType { get; set; }
 
+    /// <summary>
+    ///     Optional constraints applied to the attribute's simple type.
+    /// </summary>
     [XmlElement] public ConstraintSet? Constraints { get; set; }
 }
\ No newline at end of file
diff --git a/XSDVisualiser/Models/ConstraintSet.cs b/XSDVisualiser/Models/ConstraintSet.cs
index 2701cd9..04f8a8c 100644
--- a/XSDVisualiser/Models/ConstraintSet.cs
+++ b/XSDVisualiser/Models/ConstraintSet.cs
@@ -7,9 +7,14 @@ namespace XSDVisualiser.Core;
 /// </summary>
 public class ConstraintSet
 {
+    /// <summary>
+    ///     The qualified name of the base type this constraint set applies to, if any.
+    /// </summary>
     [XmlAttribute] public string? BaseTypeName { get; set; }
 
-    // Generic catch-all list of constraints for dynamic display and tooling
+    /// <summary>
+    ///     A catch-all list of constraint entries for dynamic display and tooling.
+    /// </summary>
     [XmlArray("Constraints")]
     [XmlArrayItem("Constraint")]
     public List<ConstraintEntry> Constraints { get; set; } = new();
diff --git a/XSDVisualiser/Models/SchemaNode.cs b/XSDVisualiser/Models/SchemaNode.cs
index 6766a7e..72cb53d 100644
--- a/XSDVisualiser/Models/SchemaNode.cs
+++ b/XSDVisualiser/Models/SchemaNode.cs
@@ -29,7 +29,10 @@ public class SchemaNode
     [XmlArrayItem("Element")]
     public List<SchemaNode> Children { get; set; } = new();
 
-    [XmlAttribute] public string? ContentModel { get; set; } // sequence | choice | all | simple
+    /// <summary>
+    ///     Content model for this node: sequence | choice | all | simple. For synthetic group nodes, may be "group".
+    /// </summary>
+    [XmlAttribute] public string? ContentModel { get; set; }
 
     /// <summary>
     ///     Human-readable documentation extracted from xsd:annotation/xsd:documentation.
@@ -38,14 +41,13 @@ public class SchemaNode
     [XmlElement]
     public string? Documentation { get; set; }
 
+    /// <summary>
+    ///     Returns a human-readable name for UI elements (prefers Name, then TypeName).
+    /// </summary>
     public override string ToString()
     {
-        // Used by AutoCompleteBox to get text for filtering and matching
-        // Prefer Name, then TypeName, and fall back to base implementation
-        if (!string.IsNullOrEmpty(Name))
-            return Name!;
-        if (!string.IsNullOrEmpty(TypeName))
-            return TypeName!;
+        if (!string.IsNullOrEmpty(Name)) return Name!;
+        if (!string.IsNullOrEmpty(TypeName)) return TypeName!;
         return base.ToString();
     }
 }
\ No newline at end of file
diff --git a/XSDVisualiser/Parsing/XsdSchemaParser.cs b/XSDVisualiser/Parsing/XsdSchemaParser.cs
index 1e8ab54..2e46746 100644
--- a/XSDVisualiser/Parsing/XsdSchemaParser.cs
+++ b/XSDVisualiser/Parsing/XsdSchemaParser.cs
@@ -4,10 +4,18 @@ using System.Xml.Schema;
 
 namespace XSDVisualiser.Core;
 
+/// <summary>
+///     Parses XML Schema (XSD) into a simplified model for visualization and tooling.
+/// </summary>
 public class XsdSchemaParser
 {
     private readonly XmlSchemaSet _set = new();
 
+    /// <summary>
+    ///     Reads and compiles the provided XSD file into a schema set, then produces a simplified schema model.
+    /// </summary>
+    /// <param name="xsdPath">Path to the XSD file.</param>
+    /// <returns>A populated <see cref="SchemaModel"/> representing global elements and their structures.</returns>
     public SchemaModel Parse(string xsdPath)
     {
         _set.XmlResolver = new XmlUrlResolver();
@@ -34,8 +42,7 @@ public class XsdSchemaParser
 
     private void ValidationCallback(object? sender, ValidationEventArgs e)
     {
-        // For now, we do not throw; we capture compiled info best-effort.
-        // Console.Error.WriteLine($"[XSD Validation {e.Severity}] {e.Message}");
+        // Intentionally no-op: schema is parsed best-effort without throwing on compile warnings/errors.
     }
 
     private SchemaNode BuildNodeForElement(XmlSchemaElement element, string? parentContentModel)
diff --git a/XSDVisualiser/Utils/XmlValidation.cs b/XSDVisualiser/Utils/XmlValidation.cs
index 84aa382..ea166a6 100644
--- a/XSDVisualiser/Utils/XmlValidation.cs
+++ b/XSDVisualiser/Utils/XmlValidation.cs
@@ -11,12 +11,29 @@ namespace XSDVisualiser.Core;
 /// </summary>
 public static class XmlValidator
 {
+    /// <summary>
+    ///     Validates an XML document against the global element specified by name and optional namespace
+    ///     from the XSD located at <paramref name="xsdPath"/>.
+    /// </summary>
+    /// <param name="xsdPath">Path to the XSD file containing the target element/type definitions.</param>
+    /// <param name="elementName">The local name of the global element to validate against.</param>
+    /// <param name="elementNamespace">The namespace URI of the element; may be null to auto-detect.</param>
+    /// <param name="xmlPath">Path to the XML file to validate.</param>
+    /// <returns>Aggregated validation result with errors/warnings and diagnostics.</returns>
     public static XmlValidationResult ValidateAgainstElement(string xsdPath, string elementName, string? elementNamespace, string xmlPath)
     {
         var set = BuildSchemaSet(xsdPath);
         return ValidateAgainstElement(set, elementName, elementNamespace, xmlPath);
     }
 
+    /// <summary>
+    ///     Validates an XML document against a specific global element within an already built <see cref="XmlSchemaSet"/>.
+    /// </summary>
+    /// <param name="schemas">Compiled schema set to use for validation.</param>
+    /// <param name="elementName">The local name of the global element to validate against.</param>
+    /// <param name="elementNamespace">The namespace URI of the element; may be null to auto-detect.</param>
+    /// <param name="xmlPath">Path to the XML file to validate.</param>
+    /// <returns>Aggregated validation result with errors/warnings and diagnostics.</returns>
     public static XmlValidationResult ValidateAgainstElement(XmlSchemaSet schemas, string elementName, string? elementNamespace, string xmlPath)
     {
         var result = new XmlValidationResult();
@@ -428,15 +445,31 @@ public static class XmlValidator
     }
 }
 
+/// <summary>
+///     Aggregates XML validation outcomes, including errors, warnings, and overall validity.
+/// </summary>
 public sealed class XmlValidationResult
 {
     private readonly List<XmlValidationIssue> _issues = new();
 
+    /// <summary>
+    ///     True if no validation errors have been recorded.
+    /// </summary>
     public bool IsValid => _issues.TrueForAll(i => i.Severity != XmlSeverityType.Error);
 
+    /// <summary>
+    ///     All recorded validation issues (errors and warnings) in chronological order.
+    /// </summary>
     public IReadOnlyList<XmlValidationIssue> Issues => _issues;
 
+    /// <summary>
+    ///     All recorded validation errors.
+    /// </summary>
     public IEnumerable<XmlValidationIssue> Errors => _issues.Where(i => i.Severity == XmlSeverityType.Error);
+
+    /// <summary>
+    ///     All recorded validation warnings.
+    /// </summary>
     public IEnumerable<XmlValidationIssue> Warnings => _issues.Where(i => i.Severity == XmlSeverityType.Warning);
 
     internal void AddError(string message, int? line = null, int? position = null) =>
@@ -446,6 +479,13 @@ public sealed class XmlValidationResult
         _issues.Add(new XmlValidationIssue(XmlSeverityType.Warning, message, line ?? 0, position ?? 0));
 }
 
+/// <summary>
+///     Represents a single validation issue (error or warning) with optional location information.
+/// </summary>
+/// <param name="Severity">Issue severity (Error or Warning).</param>
+/// <param name="Message">Human-readable description of the issue.</param>
+/// <param name="LineNumber">Line number in the XML where the issue occurred, if available.</param>
+/// <param name="LinePosition">Column position in the XML where the issue occurred, if available.</param>
 public sealed record XmlValidationIssue(XmlSeverityType Severity, string Message, int LineNumber, int LinePosition);