diff --git a/apps/desktop/.env.example b/apps/desktop/.env.example
index b2d236e4..0ee71ca1 100644
--- a/apps/desktop/.env.example
+++ b/apps/desktop/.env.example
@@ -97,3 +97,10 @@ RENDERER_VITE_API_URL=http://localhost:8080
 # Read by core package via process.env.MULTICA_API_URL at runtime
 # Production example: https://api.multica.ai
 MULTICA_API_URL=http://localhost:8080
+
+# SMC_DATA_DIR
+# Root data directory override - Isolates dev data from production.
+# When set, all data (sessions, credentials, profiles, app-state, etc.)
+# is stored under this directory instead of ~/.super-multica.
+# Supports ~ expansion. Set automatically by scripts/dev-local.sh.
+# SMC_DATA_DIR=~/.super-multica-dev
diff --git a/package.json b/package.json
index e6fb4696..87d40501 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
     "mu": "pnpm --filter @multica/cli dev",
     "dev": "turbo build --filter=@multica/types --filter=@multica/utils --filter=@multica/core && concurrently -n types,utils,core,desktop -c blue,green,yellow,cyan \"pnpm --filter @multica/types dev\" \"pnpm --filter @multica/utils dev\" \"pnpm --filter @multica/core dev\" \"pnpm --filter @multica/desktop dev\"",
     "dev:desktop": "pnpm --filter @multica/desktop dev",
-    "dev:desktop:reset": "rm -rf ~/.super-multica && echo '✓ Deleted ~/.super-multica - Fresh install state restored'",
+    "dev:desktop:reset": "rm -rf ~/.super-multica && rm -rf ~/.super-multica-dev && echo '✓ Deleted ~/.super-multica and ~/.super-multica-dev - Fresh install state restored'",
     "dev:desktop:fresh": "pnpm dev:desktop:reset && pnpm dev:desktop",
     "dev:desktop:onboarding": "pnpm --filter @multica/desktop dev:onboarding",
     "dev:gateway": "pnpm --filter @multica/gateway dev",
diff --git a/scripts/reset-user-data.sh b/scripts/reset-user-data.sh
index b56f929a..8981aa2f 100755
--- a/scripts/reset-user-data.sh
+++ b/scripts/reset-user-data.sh
@@ -15,6 +15,15 @@ else
   echo "  $MULTICA_DATA_DIR does not exist, skipping"
 fi
 
+# Dev data directory (used by pnpm dev:local)
+MULTICA_DEV_DIR="$HOME/.super-multica-dev"
+if [ -d "$MULTICA_DEV_DIR" ]; then
+  echo "  Removing $MULTICA_DEV_DIR"
+  rm -rf "$MULTICA_DEV_DIR"
+else
+  echo "  $MULTICA_DEV_DIR does not exist, skipping"
+fi
+
 # Electron app data (macOS)
 if [[ "$OSTYPE" == "darwin"* ]]; then
   ELECTRON_APP_DATA="$HOME/Library/Application Support/super-multica"