diff --git a/AGENTS.md b/AGENTS.md
index f3ca1519..f9b17121 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -8,3 +8,7 @@
 - Follow existing format for CHANGES.md additions
 - If the PR fixes an existing issue, link it to that issue so that the issue can be automatically closed on merge
 - Do not create a new issue to accompany a PR, it clogs up peoples inboxes
+
+## Code guidelines
+- Changes to the behaviour of an extra, or other syntax feature, should go in the Wiki page for that extra/feature, not in the README
+- Avoid using characters that can't be easily typed on a keyboard, unless required. Prefer plain ASCII in source code
\ No newline at end of file