From 7db7734b0e2c4b9f3d408d4aa86d30a9b8f18e99 Mon Sep 17 00:00:00 2001
From: "Y. Meyer-Norwood" <106889957+norwd@users.noreply.github.com>
Date: Mon, 10 Aug 2026 13:43:24 +1200
Subject: [PATCH] Add missing instructions for non-happy paths

---
 exercises/practice/phone-number/.docs/instructions.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/exercises/practice/phone-number/.docs/instructions.md b/exercises/practice/phone-number/.docs/instructions.md
index 5d4d3739..806947e2 100644
--- a/exercises/practice/phone-number/.docs/instructions.md
+++ b/exercises/practice/phone-number/.docs/instructions.md
@@ -31,4 +31,6 @@ should all produce the output
 
 `6139950253`
 
+Any invalid phone number should produce a `null` output.
+
 **Note:** As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.