diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 2d553159b70..0c2002ae401 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -107,6 +107,9 @@ It is fine to implement more and more of a feature across commits, but be sure t
 - Do not add or change existing dependencies unless asked to.
 - Do not remove any debug assertions or panic calls. Existing assertions are never too strict or incorrect.
 - Do not use the `timeout` command when running tests or other commands, unless specifically debugging a hanging issue. Commands should be run directly without timeout wrappers in normal operation.
+- Do not summarize new changes in any markdown files in the repo. Specifically:
+  - `tsc/CHANGES.md` is a historical artifact for the 6.0 to 7.0 migration, not a live document.
+  - `CONTRIBUTING.md` only documents high-level build tool instructions, not their implementation details.
 
 # PR Template