diff --git a/package.json b/package.json
index d823bd8..24e0838 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,8 @@
 		"src/pwa/icons/",
 		"README.md",
 		"CHANGELOG.md",
-		"LICENSE"
+		"LICENSE",
+		"scripts/postinstall.mjs"
 	],
 	"publishConfig": {
 		"provenance": true
@@ -55,7 +56,8 @@
 		"test:pw:chromium": "playwright test --project=chromium-android",
 		"test:pw:webkit": "playwright test --project=webkit-iphone",
 		"release": "semantic-release",
-		"prepublishOnly": "pnpm run lint:ox && pnpm run lint:knip && pnpm run build:dist && pnpm run lint:publint"
+		"prepublishOnly": "pnpm run lint:ox && pnpm run lint:knip && pnpm run build:dist && pnpm run lint:publint",
+		"postinstall": "node scripts/postinstall.mjs"
 	},
 	"devDependencies": {
 		"@biomejs/biome": "^1.9.0",
diff --git a/scripts/postinstall.mjs b/scripts/postinstall.mjs
new file mode 100644
index 0000000..472d575
--- /dev/null
+++ b/scripts/postinstall.mjs
@@ -0,0 +1,17 @@
+// Workaround for microsoft/node-pty#850 — spawn-helper prebuild ships without
+// execute permission on macOS, causing "posix_spawnp failed" at runtime.
+// Remove this script once node-pty >=1.2.0 stable is released and we upgrade.
+import { chmodSync, existsSync } from 'node:fs'
+import { createRequire } from 'node:module'
+import { dirname, join } from 'node:path'
+
+const require = createRequire(import.meta.url)
+try {
+	const ptyDir = dirname(require.resolve('node-pty/package.json'))
+	for (const arch of ['darwin-arm64', 'darwin-x64']) {
+		const helper = join(ptyDir, 'prebuilds', arch, 'spawn-helper')
+		if (existsSync(helper)) chmodSync(helper, 0o755)
+	}
+} catch {
+	// node-pty not found, skip
+}