diff --git a/best_practices.md b/best_practices.md
index c8b92015c14..51c3729cd0d 100644
--- a/best_practices.md
+++ b/best_practices.md
@@ -5,6 +5,8 @@
 
 ## Pull requests
 
+* PRs MUST include a non-empty description explaining what the change does and why
+* PRs without a description should be flagged as incomplete
 * the commit series in the PR should be _linear_ (it **should not contain merge commits**). This is necessary because we want to be able to [bisect](https://en.wikipedia.org/wiki/Bisection_(software_engineering)) bugs easily. Rewrite history/perform a rebase if necessary
 * PRs should be issued against the **develop** branch: we never pull directly into **master**
 * PRs **should not have conflicts** with develop. If there are, please resolve them rebasing and force-pushing