Added mailboxes as local data sources (#1022)

app/Tests/Tools/ToolCalling/ToolParameterSchemaBuilderTests.cs

@@ -30,6 +30,18 @@ public sealed class ToolParameterSchemaBuilderTests
         });
     }
 
+    [Test]
+    public void AnOptionalBooleanIsABooleanWhichMayBeLeftOut()
+    {
+        var schema = Built(ToolParameterSchemaBuilder.Create().OptionalBoolean("is_unread", "Unread mails only."));
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(schema["properties"]!["is_unread"]!["type"]!.GetValue<string>(), Is.EqualTo("boolean"));
+            Assert.That(schema["required"]!.AsArray(), Is.Empty);
+        });
+    }
+
     [Test]
     public void AListWithoutChoicesTakesAnyString()
     {