diff --git a/Code-Style.md b/Code-Style.md
index e4cd520..5343484 100644
--- a/Code-Style.md
+++ b/Code-Style.md
@@ -17,6 +17,7 @@
   and given appropriate descriptive information
   _or_ return an error defined (as public variable) in that package.
   Example: `other.Error("auth", "failed to do something important", originalError)`
+- Returned http errors must use `git.mstar.dev/mstar/goutils/webutils.ProblemDetails(StatusOnly)`.
 
 ## JS/TS