diff --git a/package.json b/package.json
index 8740e10..91ecbef 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "node": ">=24"
   },
   "scripts": {
-    "build": "pika build",
+    "build": "pika build && node scripts/fix-package-json.js",
     "prerelease": "pnpm install --force && pnpm run lint && pnpm run tsc && pnpm run build",
     "release": "npm publish ./pkg",
     "lint": "js-tools lint",
diff --git a/scripts/fix-package-json.js b/scripts/fix-package-json.js
new file mode 100644
index 0000000..c11c7d2
--- /dev/null
+++ b/scripts/fix-package-json.js
@@ -0,0 +1,21 @@
+// Script to fix the package.json files map. This is needed because npm changed the file matching behavior in npm@9.
+// And pika does not support the new behavior.
+// @see https://github.com/octokit/plugin-retry.js/issues/405
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const { EOL } = require('os');
+
+const pkgPath = path.join(__dirname, '../pkg/package.json');
+const pkg = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
+
+pkg.files = pkg.files.map((file) => {
+  if (file.endsWith('/')) {
+    return file + '**';
+  }
+  return file;
+});
+
+fs.writeFileSync(pkgPath, JSON.stringify(pkg, null, 2) + EOL, 'utf8');