diff --git a/docs/docs/origins-and-destinations.mdx b/docs/docs/origins-and-destinations.mdx
index f8dfaec..1173116 100644
--- a/docs/docs/origins-and-destinations.mdx
+++ b/docs/docs/origins-and-destinations.mdx
@@ -27,10 +27,18 @@ Some networks are currently unable to act as destination chains because the call
 
 ## Mainnet Chains
 
+:::info[Origin/Destination]
+Origin is the chain where events originate and are read from. Destination is the chain where callbacks are delivered in response to those events. Mainnets and testnets must not be mixed. If origin is a mainnet, destination must also be a mainnet, and vice versa.
+:::
+
 <MainnetChainTable />
 
 ## Testnet Chains
 
+:::info[Origin/Destination]
+Origin is the chain where events originate and are read from. Destination is the chain where callbacks are delivered in response to those events. Mainnets and testnets must not be mixed. If origin is a testnet, destination must also be a testnet, and vice versa.
+:::
+
 <TestnetChainTable />
 
 [//]: # (emojis for status ✅ ➖ ⌛)