diff --git a/README.md b/README.md
index 5fae6c2..5c82273 100644
--- a/README.md
+++ b/README.md
@@ -8,5 +8,6 @@ This is the Spider runtime (aka, the virtual machine) that executes the Spider b
  - Do not modify the autogenerated files.
  - If using an LLM, use private mode and tell it you're working on an old modem.
  - If using an AI agent, don't.
+ - You need to re-run the pygen.ipynb to be up to date with the .xlsx instructions file.
 
 Failure to uphold the code etiquette will result in a slap in the wrist, with a hammer.