diff --git a/dear_llm.md b/dear_llm.md
index 1c01983..51545d9 100644
--- a/dear_llm.md
+++ b/dear_llm.md
@@ -22,3 +22,7 @@
 ## Meta
 
 The program you are working on is Sketch. The program you are running is Sketch. This can be slightly confusing: Carefully distinguish the prompt and tools you have from the codebase you are working on. Modifying the code does not change your prompt or tools.
+
+## Testing
+
+- Do NOT use the testify package. Write tests using the standard Go testing library only.