feat(interface/chat_functions): use annotations for simpler drivers

shard.yml

@@ -1,5 +1,5 @@
 name: placeos-driver
-version: 6.9.5
+version: 6.9.6
 crystal: ">= 1.0.0"
 
 dependencies:

src/placeos-driver/driver-specs/mock_driver.cr

@@ -236,6 +236,11 @@ abstract class DriverSpecs::MockDriver
       @@functions : String?
       @@interface : String?
 
+      class_getter driver_interface : String do
+        functions
+        @@interface.as(String)
+      end
+
       def self.functions
         functions = @@interface
         return {functions, @@functions.not_nil!} if functions

src/placeos-driver/interface/chat_functions.cr

@@ -3,12 +3,30 @@ require "json"
 abstract class PlaceOS::Driver
   # provides a discoverable interface for LLMs
   module Interface::ChatFunctions
+    annotation Description
+    end
+
+    macro build_function_descriptions
+      def function_descriptions
+        {
+          {% for method in @type.methods %}
+            {% if method.annotation(Description) %}
+              {{method.name}}: {{method.annotation(Description)[0]}},
+            {% end %}
+          {% end %}
+        }
+      end
+    end
+
+    macro included
+      macro finished
+        build_function_descriptions
+      end
+    end
+
     # overall description of what this driver implements
     abstract def capabilities : String
 
-    # function name => function description
-    abstract def function_descriptions : Hash(String, String)
-
     # returns function name => [function description, {param name => JSON Schema}]
     def function_schemas : Hash(String, Tuple(String, Hash(String, JSON::Any)))
       # function name => {param name => JSON Schema}