diff --git a/dev-docs/bidder-adaptor.md b/dev-docs/bidder-adaptor.md
index 501c82bd8f..1246c058b8 100644
--- a/dev-docs/bidder-adaptor.md
+++ b/dev-docs/bidder-adaptor.md
@@ -40,6 +40,7 @@ In order to provide a fast and safe header bidding environment for publishers, t
 * *Bid responses may not use JSONP*: All requests must be AJAX with JSON responses.
 * *All user-sync activity must be registered via the provided functions*: The platform will place all registered syncs in the page after the auction is complete, subject to publisher configuration.
 * *Adapters may not use the `$$PREBID_GLOBAL$$` variable*: Instead, they must load any necessary functions and call them directly.
+* *Adapters may not override standard ad server targeting*: Do not override, or set default values for any of the standard targeting variables: hb_adid, hb_bidder, hb_pb, hb_deal, or hb_size, hb_source, hb_format.
 
 {: .alert.alert-danger :}
 Failure to follow any of the above conventions could lead to delays in approving your adapter for inclusion in Prebid.js.