Support multiple web search backends: SearXNG, Staan, and Tavily (#948)

app/MindWork AI Studio/Tools/ToolCallingSystem/ToolSettingsSchemaBuilder.cs

@@ -15,8 +15,24 @@ public sealed class ToolSettingsSchemaBuilder
     private readonly Dictionary<string, ToolSettingsFieldDefinition> properties = new(StringComparer.Ordinal);
     private readonly HashSet<string> requiredNames = new(StringComparer.Ordinal);
 
+    private string currentGroup = string.Empty;
+
     public static ToolSettingsSchemaBuilder Create() => new();
 
+    /// <summary>
+    /// Puts every field declared after this call into one group.
+    /// </summary>
+    /// <remarks>
+    /// Call it again with another name to start the next group, or with an empty name to
+    /// leave grouping behind. Groups are shown in the order in which they first appear here,
+    /// and so are the fields within them.
+    /// </remarks>
+    public ToolSettingsSchemaBuilder InGroup(string groupKey)
+    {
+        this.currentGroup = groupKey;
+        return this;
+    }
+
     /// <summary>
     /// A field the tool cannot work without.
     /// </summary>
@@ -35,6 +51,16 @@ public sealed class ToolSettingsSchemaBuilder
 
     public ToolSettingsSchemaBuilder OptionalChoice(string name, string optionSource) => this.Add(name, isRequired: false, optionSource: optionSource);
 
+    /// <summary>
+    /// An optional field whose value is picked from a short list the tool spells out itself.
+    /// </summary>
+    /// <remarks>
+    /// Use this for values only one tool knows, such as the markets a single search service
+    /// offers. Anything the app maintains elsewhere belongs in an option source instead, which
+    /// also gives the user a translated name rather than the raw value.
+    /// </remarks>
+    public ToolSettingsSchemaBuilder OptionalEnum(string name, params string[] values) => this.Add(name, isRequired: false, enumValues: values);
+
     /// <summary>
     /// A field kept in the operating system's keyring rather than in the settings file.
     /// </summary>
@@ -48,12 +74,14 @@ public sealed class ToolSettingsSchemaBuilder
         Required = [..this.requiredNames],
     };
 
-    private ToolSettingsSchemaBuilder Add(string name, bool isRequired, string optionSource = "", bool isSecret = false)
+    private ToolSettingsSchemaBuilder Add(string name, bool isRequired, string optionSource = "", bool isSecret = false, IReadOnlyList<string>? enumValues = null)
     {
         this.properties[name] = new ToolSettingsFieldDefinition
         {
             OptionSource = optionSource,
+            EnumValues = enumValues?.ToList() ?? [],
             Secret = isSecret,
+            Group = this.currentGroup,
         };
 
         if (isRequired)