diff --git a/workdir/dev.sh b/workdir/dev.sh
index db349fd..c798d46 100755
--- a/workdir/dev.sh
+++ b/workdir/dev.sh
@@ -1,9 +1,8 @@
 #!/usr/bin/env bash
 # Start server + frontend in dev mode using tmux.
 # Run from workdir/ — this directory is the CW workspace.
+# Layout: server (left) | web (right)
 # Usage: ./dev.sh [session-name]
-#   ./dev.sh        → session "cw"
-#   ./dev.sh myapp  → custom session name
 
 set -e
 
@@ -21,13 +20,20 @@ if tmux has-session -t "$SESSION" 2>/dev/null; then
   exec tmux attach-session -t "$SESSION"
 fi
 
-# Server: runs from workdir/ so cw finds .cwrc here
-tmux new-session  -d -s "$SESSION" -n server -c "$WORKDIR"
-tmux send-keys    -t "$SESSION:server" "npx tsx watch $ROOT/apps/server/bin/cw.ts --server" Enter
+# Single window, split vertically: server on left, web on right
+tmux new-session -d -s "$SESSION" -n dev -c "$WORKDIR"
 
-# Frontend: runs from project root via npm workspace
-tmux new-window   -t "$SESSION" -n web -c "$ROOT"
-tmux send-keys    -t "$SESSION:web"    "npm run dev --workspace=apps/web" Enter
+# Left pane: server (runs from workdir/ so cw finds .cwrc here)
+tmux send-keys -t "$SESSION:dev" "npx tsx watch $ROOT/apps/server/bin/cw.ts --server" Enter
+
+# Right pane: web dev server
+tmux split-window -t "$SESSION:dev" -h -c "$ROOT"
+tmux send-keys    -t "$SESSION:dev" "npm run dev --workspace=apps/web" Enter
+
+# Give server pane slightly more width (60/40 split)
+tmux resize-pane -t "$SESSION:dev.left" -x "60%"
+
+# Keep focus on server pane
+tmux select-pane -t "$SESSION:dev.left"
 
-tmux select-window -t "$SESSION:server"
 exec tmux attach-session -t "$SESSION"