diff --git a/tools/gutenberg/build-gutenberg.js b/tools/gutenberg/build-gutenberg.js
index cf6dd973953bc..1dc1f73a4ec69 100644
--- a/tools/gutenberg/build-gutenberg.js
+++ b/tools/gutenberg/build-gutenberg.js
@@ -145,10 +145,10 @@ async function main() {
 		// On Unix, arguments are passed directly without shell parsing
 		const baseUrlArg =
 			process.platform === 'win32'
-				? '--base-url="includes_url( \'build\' )"'
-				: "--base-url=includes_url( 'build' )";
+				? '--base-url="includes_url( \'build/\' )"'
+				: "--base-url=includes_url( 'build/' )";
 
-		await exec( 'npm', [ 'run', 'build', '--', '--fast', baseUrlArg ], {
+		await exec( 'npm', [ 'run', 'build', '--', '--skip-types', baseUrlArg ], {
 			cwd: gutenbergDir,
 		} );
 
diff --git a/tools/gutenberg/copy-gutenberg-build.js b/tools/gutenberg/copy-gutenberg-build.js
index e5332f806f74a..dda8ab39d630e 100644
--- a/tools/gutenberg/copy-gutenberg-build.js
+++ b/tools/gutenberg/copy-gutenberg-build.js
@@ -39,7 +39,7 @@ const COPY_CONFIG = {
 	// PHP infrastructure files (to wp-includes/build/)
 	phpInfrastructure: {
 		destination: 'build',
-		files: [ 'routes.php', 'pages.php' ],
+		files: [ 'routes.php', 'pages.php', 'constants.php' ],
 		directories: [ 'pages', 'routes' ],
 	},