diff --git a/justfile b/justfile
index aa2d1d3..e84e600 100644
--- a/justfile
+++ b/justfile
@@ -1,30 +1,35 @@
 host := `hostname`
 key_services := "github gradescope"
 
+# Rebuild the system and switch immediately
 rebuild:
     sudo nixos-rebuild switch --flake .#{{host}}
 
+# Update flake.lock
 update:
-    sudo nix flake update
+    nix flake update
 
+# Clean up old generations and optimize store
 gc:
-    sudo nix-env --delete-generations +3
-    sudo nix-store --gc
+    sudo nix-collect-garbage -d
+    sudo nix-store --optimise
+    sudo nixos-rebuild boot --flake .#{{host}}
 
-# Generate high-strength, post-quantum ready SSH keys without passphrases
+# Generate Ed25519 SSH keys for each configured service
 gen-keys:
     #!/usr/bin/env bash
     set -euo pipefail
+
     mkdir -p ~/.ssh
-    
+    chmod 700 ~/.ssh
+
     for service in {{key_services}}; do
-        FILE="$HOME/.ssh/id_$service"
-        
-        if [ -f "$FILE" ]; then
-            echo "skipping: $FILE already exists."
-        else
-            echo "generating: $FILE"
-            ssh-keygen -t ed25519 -a 100 -o -f "$FILE" -N ""
+        file="$HOME/.ssh/id_$service"
+        if [ -f "$file" ]; then
+            echo "skipping: $file already exists"
+            continue
         fi
+        echo "generating: $file"
+        ssh-keygen -t ed25519 -f "$file" -N "" -C "$service@$(hostname -s)"
     done