diff --git a/src/synthesis/clean.test.ts b/src/synthesis/clean.test.ts
index 2e1a3f04..cfcd3798 100644
--- a/src/synthesis/clean.test.ts
+++ b/src/synthesis/clean.test.ts
@@ -86,6 +86,14 @@ void test("cleanMarkdown works fine with url", () => {
     cleanMarkdown(mockMessage("https://discord.com/channels/0/0")),
     " 外部サーバーのチャンネル ",
   );
+  assert.strictEqual(
+    cleanMarkdown(mockMessage("https://ptb.discord.com/channels/0/0")),
+    " 外部サーバーのチャンネル ",
+  );
+  assert.strictEqual(
+    cleanMarkdown(mockMessage("https://canary.discord.com/channels/0/0")),
+    " 外部サーバーのチャンネル ",
+  );
   assert.strictEqual(
     cleanMarkdown(mockMessage("https://discord.com/channels/0/0/0")),
     " 外部サーバーのメッセージ ",