Added a semantic search tool (#1005)

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

@@ -0,0 +1,23 @@
+namespace AIStudio.Tools.ToolCallingSystem;
+
+/// <summary>
+/// How a tool comes to be offered to a model.
+/// </summary>
+public enum ToolActivation
+{
+    /// <summary>
+    /// Offered when it was selected: by the user, a chat template, a policy, or an assistant.
+    /// </summary>
+    SELECTION,
+
+    /// <summary>
+    /// Offered whenever the chat calls for it, without anybody selecting it.
+    /// </summary>
+    /// <remarks>
+    /// For a tool whose use is already decided somewhere else. Semantic Search is such a tool: the
+    /// user picks the data sources of a chat, and a second switch for searching them would only be
+    /// a way to contradict the first one. Such a tool never appears in a selection, and it decides
+    /// on each request whether it has anything to offer.
+    /// </remarks>
+    CONTEXT,
+}