Use nixvim

modules/home-manager/coding/neovim/plugins/harpoon.nix

@@ -0,0 +1,47 @@
+{ config, lib, ... }:
+
+let
+  leaderBinding = key: command: {
+    key = "<leader>${key}";
+    action = "<cmd>${command}<CR>";
+    options.silent = true;
+  };
+in
+{
+  plugins.harpoon = {
+    enable = true;
+    enableTelescope = true;
+  };
+
+  keymaps = lib.mkIf config.plugins.harpoon.enable (
+    [
+      {
+        key = "<leader>a";
+        action.__raw = "function() require'harpoon':list():add() end";
+      }
+
+      {
+        key = "<C-e>";
+        action.__raw = ''
+          function()
+            require 'harpoon'.ui:toggle_quick_menu(require'harpoon':list())
+          end
+        '';
+      }
+    ]
+    ++ (map
+      (num: leaderBinding "${toString num}" "lua require(\"harpoon\"):list():select(${toString num})")
+      [
+        1
+        2
+        3
+        4
+        5
+        6
+        7
+        8
+        9
+      ]
+    )
+  );
+}