Simpler

app/[slug]/page.js

···
 
 export default async function PostPage({ params }) {
   const file = await readFile("./public/" + params.slug + "/index.md", "utf8");
+  let postComponents = {};
+  try {
+    postComponents = await import(
+      "../../public/" + params.slug + "/components.js"
+    );
+  } catch (e) {
+    if (!e || e.code !== "MODULE_NOT_FOUND") {
+      throw e;
+    }
+  }
   const { content, data } = matter(file);
   const discussUrl = `https://x.com/search?q=${encodeURIComponent(
     `https://overreacted.io/${params.slug}/`,
···
               a: Link,
               Server: Server,
               Client: Client,
+              ...postComponents,
             }}
             options={{
               mdxOptions: {

patches/next-mdx-remote+4.4.1.patch

···
-diff --git a/node_modules/next-mdx-remote/dist/rsc.js b/node_modules/next-mdx-remote/dist/rsc.js
-index 8ab7d78..a75b600 100644
---- a/node_modules/next-mdx-remote/dist/rsc.js
-+++ b/node_modules/next-mdx-remote/dist/rsc.js
-@@ -2701,6 +2701,8 @@ async function serialize(source, { scope = {}, mdxOptions = {}, parseFrontmatter
-     };
- }
- 
-+import Module from "node:module";
-+
- /**
-  * Copyright (c) HashiCorp, Inc.
-  * SPDX-License-Identifier: MPL-2.0
-@@ -2722,8 +2724,9 @@ async function compileMDX({ source, options, components = {}, }) {
-     // and all our components in scope for the function, which is the case here
-     // we pass the names (via keys) in as the function's args, and execute the
-     // function with the actual values.
--    const hydrateFn = Reflect.construct(Function, keys.concat(`${compiledSource}`));
--    const Content = hydrateFn.apply(hydrateFn, values).default;
-+    const AsyncFunction = Object.getPrototypeOf(async function() { }).constructor;
-+    const hydrateFn = AsyncFunction(...keys.concat(`${compiledSource}`));
-+    const Content = (await hydrateFn.apply(hydrateFn, values)).default;
-     return {
-         content: React.createElement(Content, { components: components }),
-         frontmatter,