From c5a93180e12bc478d5cc67f57b418a0ef495f7c8 Mon Sep 17 00:00:00 2001
From: Sarah Schneider <sarahs@users.noreply.github.com>
Date: Thu, 6 Nov 2025 19:06:44 -0500
Subject: [PATCH] Clarify error message about category frontmatter (#58394)

---
 src/frame/lib/frontmatter.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/frame/lib/frontmatter.ts b/src/frame/lib/frontmatter.ts
index bd8267a44d38..3beca783efd6 100644
--- a/src/frame/lib/frontmatter.ts
+++ b/src/frame/lib/frontmatter.ts
@@ -353,6 +353,9 @@ export const schema: Schema = {
     // START category-landing tags
     category: {
       type: 'array',
+      errorMessage: `must be an array, which is written in frontmatter like:
+category:
+  - Category Name`,
     },
     complexity: {
       type: 'array',