diff --git a/nix/shell.nix b/nix/shell.nix
index c5f8f9c2..c9ea77c7 100644
--- a/nix/shell.nix
+++ b/nix/shell.nix
@@ -53,13 +53,9 @@ let
 
     echo "🚀 Starting development services..."
 
-    # Check if already started
-    if [ -f "${servicesFlag}" ]; then
-      echo "✓ Services already running (remove ${servicesFlag} to force restart)"
-      exit 0
-    fi
-
-    # Check if cluster needs reinitialization (PG extensions or version changed)
+    # Check if PG version/extensions changed and reinit if needed.
+    # Must run BEFORE the servicesFlag guard so already-running clusters
+    # get reinitialized when extensions or versions change.
     pg_needs_reinit=false
     if [ -d "${pgDataDir}" ] && [ -f "${pgVersionFile}" ]; then
       if [ "$(cat ${pgVersionFile})" != "${pg}" ]; then
@@ -68,18 +64,22 @@ let
       fi
     fi
     if [ -d "${pgDataDir}" ] && [ ! -f "${pgVersionFile}" ]; then
-      # Legacy cluster without version file, reinit to be safe
       pg_needs_reinit=true
     fi
 
     if $pg_needs_reinit; then
-      echo "🗑️  Removing old PostgreSQL cluster..."
-      # Stop if running
+      echo "🗑️  Stopping old PostgreSQL and removing cluster..."
       ${pg}/bin/pg_ctl -D ${pgDataDir} stop -m fast 2>/dev/null || true
       rm -rf ${pgDataDir}
       rm -f ${servicesFlag}
     fi
 
+    # Check if already started (with correct version)
+    if [ -f "${servicesFlag}" ]; then
+      echo "✓ Services already running (remove ${servicesFlag} to force restart)"
+      exit 0
+    fi
+
     # Initialize PostgreSQL if needed
     if [ ! -d "${pgDataDir}" ]; then
       echo "📦 Initializing PostgreSQL database..."