feat: Add --reasoning-effort CLI parameter to control model reasoning…

… effort

aider/args.py

@@ -304,6 +304,11 @@ def get_parser(default_config_files, git_root):
         default=2,
         help="Multiplier for map tokens when no files are specified (default: 2)",
     )
+    group.add_argument(
+        "--reasoning-effort",
+        type=float,
+        help="Control how much effort the model spends on reasoning (0.0-1.0)",
+    )
 
     ##########
     group = parser.add_argument_group("History Files")

aider/main.py

@@ -778,10 +778,13 @@ def get_io(pretty):
     )
 
     # add --reasoning-effort cli param
-    # defaults to None
-    # if present, set main_model.extra_params["extra_body"]["reasoning_effort"] = <val>
-    # be careful, not all those dicts will be initialized
-    # ai!
+    if args.reasoning_effort is not None:
+        if not hasattr(main_model, 'extra_params'):
+            main_model.extra_params = {}
+        if 'extra_body' not in main_model.extra_params:
+            main_model.extra_params['extra_body'] = {}
+        main_model.extra_params['extra_body']['reasoning_effort'] = args.reasoning_effort
+
     if args.copy_paste and args.edit_format is None:
         if main_model.edit_format in ("diff", "whole"):
             main_model.edit_format = "editor-" + main_model.edit_format