diff --git a/.changeset/calm-rats-remain.md b/.changeset/calm-rats-remain.md
new file mode 100644
index 0000000..b6393b0
--- /dev/null
+++ b/.changeset/calm-rats-remain.md
@@ -0,0 +1,5 @@
+---
+'starlight-obsidian': minor
+---
+
+Improves error message when the `output` directory configuration option is invalid.
diff --git a/packages/starlight-obsidian/index.ts b/packages/starlight-obsidian/index.ts
index f102143..ba825ef 100644
--- a/packages/starlight-obsidian/index.ts
+++ b/packages/starlight-obsidian/index.ts
@@ -6,6 +6,7 @@ import { z } from 'astro/zod'
 
 import { starlightObsidianIntegration } from './libs/integration'
 import { getObsidianPaths, getVault } from './libs/obsidian'
+import { stripLeadingAndTrailingSlashes } from './libs/path'
 import { throwUserError } from './libs/plugin'
 import { addObsidianFiles, getSidebarFromConfig, getSidebarGroupPlaceholder, type SidebarGroup } from './libs/starlight'
 
@@ -65,7 +66,18 @@ const starlightObsidianConfigSchema = z.object({
    *
    * @default 'notes'
    */
-  output: z.string().default('notes'),
+  output: z
+    .string()
+    .default('notes')
+    .refine(
+      (value) => {
+        const label = stripLeadingAndTrailingSlashes(value)
+        return label !== '' && label !== '.' && !label.startsWith('..')
+      },
+      {
+        message: "The `output` directory cannot be empty, '.', or start with '..'.",
+      },
+    ),
   /**
    * Whether the Starlight Obsidian plugin should skip the generation of the Obsidian vault pages.
    *
diff --git a/packages/starlight-obsidian/libs/path.ts b/packages/starlight-obsidian/libs/path.ts
index 96d53b0..bb985ad 100644
--- a/packages/starlight-obsidian/libs/path.ts
+++ b/packages/starlight-obsidian/libs/path.ts
@@ -52,3 +52,17 @@ export function slashify(filePath: string) {
 export function osPath(filePath: string) {
   return filePath.replaceAll('/', path.sep)
 }
+
+function stripLeadingSlash(href: string) {
+  if (href.startsWith('/')) href = href.slice(1)
+  return href
+}
+
+function stripTrailingSlash(href: string) {
+  if (href.endsWith('/')) href = href.slice(0, -1)
+  return href
+}
+
+export function stripLeadingAndTrailingSlashes(href: string): string {
+  return stripTrailingSlash(stripLeadingSlash(href))
+}