diff --git a/config/sets.nix b/config/sets.nix
index 119873d..ddcaeec 100644
--- a/config/sets.nix
+++ b/config/sets.nix
@@ -2,7 +2,6 @@
   plugins = {
     auto-save.enable = true;
     bufferline = {
-      # TODO: remove this once you are used to not having it
       enable = true;
       settings = {
         options = {
@@ -33,15 +32,18 @@
         watch_gitdir = {follow_files = true;};
       };
     };
+
+    # FIXED: Migrated top-level booleans to Harpoon2 'settings' block
     harpoon = {
       enable = true;
       settings = {
         save_on_toggle = true;
         save_on_change = true;
-        sync_on_ui_close = false; # Equivalent to some older behaviors
-        # add other Harpoon2 specific settings here if needed
+        enter_on_sendcmd = false;
+        mark_branch = true;
       };
     };
+
     hop.enable = true;
     illuminate.enable = true;
     image.enable = true;
@@ -108,17 +110,11 @@
       };
       follow_url_func = ''
         function(url)
-              -- Open the URL in the default web browser.
-              vim.fn.jobstart({"open", url})  -- Mac OS
-              -- vim.fn.jobstart({"xdg-open", url})  -- linux
-              -- vim.cmd(':silent exec "!start ' .. url .. '"') -- Windows
-              -- vim.ui.open(url) -- need Neovim 0.10.0+
+              vim.fn.jobstart({"open", url})
             end'';
       follow_img_func = ''
         function(img)
-              vim.fn.jobstart { "qlmanage", "-p", img }  -- Mac OS quick look preview
-              -- vim.fn.jobstart({"xdg-open", url})  -- linux
-              -- vim.cmd(':silent exec "!start ' .. url .. '"') -- Windows
+              vim.fn.jobstart { "qlmanage", "-p", img }
             end'';
     };
 
@@ -144,12 +140,13 @@
     render-markdown.enable = true;
     todo-comments.enable = true;
 
+    # FIXED: Updated folding syntax and disabled auto_install for read-only Nix store
     treesitter = {
       enable = true;
       folding.enable = false;
-      settings.indent.enable = true;
       settings = {
-        auto_install = true;
+        indent.enable = true;
+        auto_install = false;
         ensure_installed = [
           "git_config"
           "git_rebase"
@@ -158,6 +155,7 @@
           "gitignore"
           "bash"
           "python"
+          "nix"
         ];
       };
     };