diff --git a/scripts/ci/verify-update-feed.js b/scripts/ci/verify-update-feed.js
new file mode 100644
index 00000000..493f1fd1
--- /dev/null
+++ b/scripts/ci/verify-update-feed.js
@@ -0,0 +1,90 @@
+#!/usr/bin/env node
+// Audits the electron-builder update feed (latest.yml / latest-mac.yml) without actually applying an update. Asserts: (a) feed parses, (b) advertised files exist locally, (c) advertised sha512 matches the on-disk file, (d) advertised size matches. A green release with a busted feed ships an update that bricks on apply for every user; this turns that class of bug red before publish.
+
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const crypto = require('crypto');
+const h = require('./lib/app-harness');
+
+function parseArgs(argv) {
+  const out = { dir: null };
+  for (let i = 0; i < argv.length; i++) if (argv[i] === '--dir') out.dir = argv[++i];
+  return out;
+}
+
+// Tiny YAML scrubber - electron-builder emits a simple flat-ish YAML with
+// list-of-files. We don't pull a dependency for this; just regex it.
+function parseFeed(text) {
+  const version = (text.match(/^version:\s*(.+)$/m) || [])[1];
+  const top = {
+    path: (text.match(/^path:\s*(.+)$/m) || [])[1],
+    sha512: (text.match(/^sha512:\s*(.+)$/m) || [])[1],
+  };
+  const files = [];
+  const re = /-\s+url:\s*(.+)\s*\n\s+sha512:\s*(.+)\s*\n\s+size:\s*(\d+)/g;
+  let m;
+  while ((m = re.exec(text))) files.push({ url: m[1].trim(), sha512: m[2].trim(), size: Number(m[3]) });
+  return { version, top, files };
+}
+
+function sha512Base64(file) {
+  const hash = crypto.createHash('sha512');
+  hash.update(fs.readFileSync(file));
+  return hash.digest('base64');
+}
+
+function feedPaths(dir) {
+  const out = [];
+  for (const f of ['latest.yml', 'latest-mac.yml', 'latest-mac-arm64.yml', 'latest-linux.yml']) {
+    const p = path.join(dir, f);
+    if (fs.existsSync(p)) out.push(p);
+  }
+  return out;
+}
+
+module.exports = { parseFeed };
+
+function main() {
+  const args = parseArgs(process.argv.slice(2));
+  const dir = args.dir || path.join(h.REPO_ROOT, 'electron', 'dist');
+  const feeds = feedPaths(dir);
+  if (feeds.length === 0) { process.stdout.write(`SKIP: no update feeds under ${dir} (this is fine for builds without --publish).\n`); process.exit(0); }
+
+  const failures = [];
+  for (const feed of feeds) {
+    process.stdout.write(`\nFeed: ${feed}\n`);
+    const text = fs.readFileSync(feed, 'utf8');
+    const parsed = parseFeed(text);
+    if (!parsed.version) { failures.push(`${feed}: no version`); continue; }
+    process.stdout.write(`  version: ${parsed.version}\n`);
+
+    if (parsed.files.length === 0) { failures.push(`${feed}: feed lists zero files`); continue; }
+    for (const f of parsed.files) {
+      const full = path.join(dir, f.url);
+      if (!fs.existsSync(full)) { failures.push(`${feed}: advertised file missing on disk: ${f.url}`); continue; }
+      const size = fs.statSync(full).size;
+      if (size !== f.size) { failures.push(`${feed}: ${f.url} size on disk ${size} != feed ${f.size}`); continue; }
+      const actualSha = sha512Base64(full);
+      if (actualSha !== f.sha512) { failures.push(`${feed}: ${f.url} sha512 mismatch (feed ${f.sha512.slice(0, 20)}... vs disk ${actualSha.slice(0, 20)}...)`); continue; }
+      process.stdout.write(`  ok ${f.url} (${(size / 1048576).toFixed(0)} MB, sha512 verified)\n`);
+    }
+
+    // The top-level path/sha512 must match one of the file entries (oneClick installer pattern).
+    if (parsed.top.path && parsed.top.sha512) {
+      const ref = parsed.files.find((f) => f.url === parsed.top.path);
+      if (!ref) failures.push(`${feed}: top-level path "${parsed.top.path}" not listed in files[]`);
+      else if (ref.sha512 !== parsed.top.sha512) failures.push(`${feed}: top-level sha512 != files[].sha512 for ${parsed.top.path}`);
+    }
+  }
+
+  if (failures.length) {
+    process.stderr.write(`\nUPDATE-FEED FAIL: ${failures.length} problem(s)\n`);
+    for (const f of failures) process.stderr.write(`  - ${f}\n`);
+    process.exit(1);
+  }
+  process.stdout.write('\nUPDATE-FEED PASS: every advertised file exists, hashes match, sizes match.\n');
+  process.exit(0);
+}
+
+if (require.main === module) main();