diff --git a/docs/rfcs/README.md b/docs/rfcs/README.md
index 4e2d1d37..ae50b3ce 100644
--- a/docs/rfcs/README.md
+++ b/docs/rfcs/README.md
@@ -18,6 +18,12 @@ cutting infrastructure.
   questions, Rollout plan. Skip what doesn't apply.
 - An RFC is a starting point for review. Comments and revisions land via PR
   edits, not separate discussion threads.
+- An RFC documents a design direction. It is **not** an invitation to file
+  implementation PRs against fragments of it. Before opening any PR that
+  implements an accepted RFC, confirm with a maintainer in the tracking
+  issue that the implementation slice is wanted and that no other
+  contributor is already building it. Speculative implementations of RFC
+  fragments without a confirmed integration site will be held.
 
 ## When to file an RFC