diff --git a/docs/ai/overview.md b/docs/ai/overview.md
index 97c7603..7456e72 100644
--- a/docs/ai/overview.md
+++ b/docs/ai/overview.md
@@ -51,6 +51,15 @@ Copilot is an AI coding assistant that integrates with editors and chats to help
 - Skills: Reusable knowledge or workflows the assistant can apply.
 - Tokens: The usage units that track AI consumption.
 
+## Instructions (Repo Rules)
+Instructions are repo-scoped rule files that auto-apply based on file patterns. They set coding or documentation standards the assistant must follow when editing matching files.
+
+Where they live:
+- The repo-level instructions directory (for example, [instructions/](../../instructions/))
+- Editor or org-level instruction files when configured by your team
+
+Instructions are always-on defaults. Agents and skills are optional and only used when you explicitly invoke them.
+
 ## Agents vs Skills (Where They Live)
 Agents are full personas or modes (for example, Task Researcher) that control how the assistant behaves end-to-end. Skills are focused, reusable workflows (for example, webapp-testing) that the assistant can load for a specific task.