diff --git a/nix/packages/by-name/tmux-sessionizer/package.nix b/nix/packages/by-name/tmux-sessionizer/package.nix
new file mode 100644
index 00000000..121ee8db
--- /dev/null
+++ b/nix/packages/by-name/tmux-sessionizer/package.nix
@@ -0,0 +1,23 @@
+{
+  writeShellApplication,
+  tmux,
+  symlinkJoin,
+}: let
+  tmux-register-session = writeShellApplication {
+    name = "__tmux-register-session";
+    runtimeInputs = [tmux];
+    text = ''
+      last=/tmp/TMUX_LAST
+      this="$(tmux display-message -p '#S')"
+      if [ ! -f "$last" ] || [ "$(cat "$last")" != "$this" ]; then
+          echo "$this" >"$last"
+      fi
+    '';
+  };
+in
+  symlinkJoin {
+    name = "tmux-sessionizer";
+    paths = [
+      tmux-register-session
+    ];
+  }