diff --git a/crates/oauth2-types/src/requests.rs b/crates/oauth2-types/src/requests.rs
index ac0770411..28203a973 100644
--- a/crates/oauth2-types/src/requests.rs
+++ b/crates/oauth2-types/src/requests.rs
@@ -807,6 +807,7 @@ pub struct IntrospectionResponse {
     pub jti: Option<String>,
 
     /// MAS extension: explicit device ID
+    /// Only used for compatibility access and refresh tokens.
     pub device_id: Option<String>,
 }