diff --git a/PR_PANEL_TEST.md b/PR_PANEL_TEST.md
new file mode 100644
index 000000000000..62ca100ad16b
--- /dev/null
+++ b/PR_PANEL_TEST.md
@@ -0,0 +1,7 @@
+# PR Panel Render Test
+
+This file exists only to exercise the GitHub/GitLab PR panel diff rendering.
+
+- Line one — added.
+- Line two — added.
+- Line three — added.
diff --git a/README.md b/README.md
index c439743cea54..40b1cb8a688e 100644
--- a/README.md
+++ b/README.md
@@ -61,3 +61,5 @@ bun install .
 Read [CONTRIBUTING.md](./CONTRIBUTING.md) before opening an issue or PR.
 
 Need support? Join the [Discord](https://discord.gg/jn4EGJjrvv).
+
+<!-- pr-panel render smoke test marker -->