diff --git a/.project/designs/serve.js b/.project/designs/serve.js
index 1b694e9b..c1621c5a 100644
--- a/.project/designs/serve.js
+++ b/.project/designs/serve.js
@@ -3,7 +3,7 @@ const http = require("http");
 const fs = require("fs");
 const path = require("path");
 
-const PORT = 7777;
+const PORT = parseInt(process.argv[2] || "7777", 10);
 const ROOT = __dirname;
 
 const MIME = {
diff --git a/run b/run
index d239543b..04a47289 100755
--- a/run
+++ b/run
@@ -23,7 +23,8 @@ usage() {
     echo -e "${YELLOW}Development${NC}"
     echo "  play                     Launch the game locally"
     echo "  editor                   Open Godot editor"
-    echo "  guide                    Start guide dev server (port 5800)"
+    echo "  guide                    Start guide dev server (port 5800)
+  designs [port]           Serve .project/designs/ HTML sketches (default port 7777)"
     echo "  lint                     Lint all (GDScript + Rust + TypeScript)"
     echo "  lint:gd                  GDScript only (gdlint + gdformat --check)"
     echo "  lint:rust                Rust only (fmt --check + clippy + machete)"
diff --git a/scripts/run/dev.sh b/scripts/run/dev.sh
index f91e6b0e..9e2c1871 100644
--- a/scripts/run/dev.sh
+++ b/scripts/run/dev.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Dev subcommands: play, editor, guide, screenshot.
+# Dev subcommands: play, editor, guide, designs, screenshot.
 #
 # Previously this file was 546L conflating lint/format/test/verify/autoplay/
 # dev-server into one module. It's now split:
@@ -50,6 +50,13 @@ cmd_guide() {
     pnpm --prefix "$GUIDE_DIR" dev
 }
 
+cmd_designs() {
+    local port="${1:-7777}"
+    echo -e "${BLUE}Starting design viewer (port ${port})...${NC}"
+    echo -e "${BLUE}  http://localhost:${port}${NC}"
+    node "$REPO_ROOT/.project/designs/serve.js" "$port"
+}
+
 cmd_screenshot() {
     "$REPO_ROOT/tools/screenshot.sh" "$@"
 }