diff --git a/browse/src/file-permissions.ts b/browse/src/file-permissions.ts
index d3d404acde..f359a13660 100644
--- a/browse/src/file-permissions.ts
+++ b/browse/src/file-permissions.ts
@@ -143,9 +143,24 @@ export function appendSecureFile(
  * `mkdir -p` with owner-only directory permissions, cross-platform.
  * Replaces `fs.mkdirSync(path, { recursive: true, mode: 0o700 })` + Windows ACL.
  * Safe to call on an existing directory — re-applies the ACL idempotently.
+ *
+ * Bun-on-Windows quirk: bun's compiled-binary fs.mkdirSync sometimes throws
+ * EEXIST even with `recursive: true` when the directory already exists (Node
+ * does not). Swallow that one case so callers don't have to wrap every
+ * invocation.
  */
 export function mkdirSecure(dirPath: string): void {
-  fs.mkdirSync(dirPath, { recursive: true, mode: 0o700 });
+  try {
+    fs.mkdirSync(dirPath, { recursive: true, mode: 0o700 });
+  } catch (err: any) {
+    if (err && err.code === 'EEXIST') {
+      const stat = fs.statSync(dirPath);
+      if (!stat.isDirectory()) throw err;
+      // Existing directory — fall through to re-apply ACL.
+    } else {
+      throw err;
+    }
+  }
   restrictDirectoryPermissions(dirPath);
 }
 
diff --git a/package.json b/package.json
index 3851a78bd7..791f3e5d79 100644
--- a/package.json
+++ b/package.json
@@ -9,7 +9,7 @@
     "make-pdf": "./make-pdf/dist/pdf"
   },
   "scripts": {
-    "build": "bun run vendor:xterm && bun run gen:skill-docs --host all; bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile design/src/cli.ts --outfile design/dist/design && bun build --compile make-pdf/src/cli.ts --outfile make-pdf/dist/pdf && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && ( git rev-parse HEAD 2>/dev/null || true ) > browse/dist/.version && ( git rev-parse HEAD 2>/dev/null || true ) > design/dist/.version && ( git rev-parse HEAD 2>/dev/null || true ) > make-pdf/dist/.version && chmod +x browse/dist/browse browse/dist/find-browse design/dist/design make-pdf/dist/pdf bin/gstack-global-discover && (rm -f .*.bun-build || true)",
+    "build": "bun run vendor:xterm && bun run gen:skill-docs --host all; bun build --compile browse/src/cli.ts --outfile browse/dist/browse && bun build --compile browse/src/find-browse.ts --outfile browse/dist/find-browse && bun build --compile design/src/cli.ts --outfile design/dist/design && bun build --compile make-pdf/src/cli.ts --outfile make-pdf/dist/pdf && bun build --compile bin/gstack-global-discover.ts --outfile bin/gstack-global-discover && bash browse/scripts/build-node-server.sh && bash -c '(git rev-parse HEAD 2>/dev/null || true) > browse/dist/.version' && bash -c '(git rev-parse HEAD 2>/dev/null || true) > design/dist/.version' && bash -c '(git rev-parse HEAD 2>/dev/null || true) > make-pdf/dist/.version' && chmod +x browse/dist/browse browse/dist/find-browse design/dist/design make-pdf/dist/pdf bin/gstack-global-discover && bash -c 'rm -f .*.bun-build || true'",
     "vendor:xterm": "mkdir -p extension/lib && cp node_modules/xterm/lib/xterm.js extension/lib/xterm.js && cp node_modules/xterm/css/xterm.css extension/lib/xterm.css && cp node_modules/xterm-addon-fit/lib/xterm-addon-fit.js extension/lib/xterm-addon-fit.js",
     "dev:make-pdf": "bun run make-pdf/src/cli.ts",
     "dev:design": "bun run design/src/cli.ts",