diff --git a/data/api/client-server/administrative_contact.yaml b/data/api/client-server/administrative_contact.yaml
index eddb2b01..13ebff16 100644
--- a/data/api/client-server/administrative_contact.yaml
+++ b/data/api/client-server/administrative_contact.yaml
@@ -201,6 +201,11 @@ paths:
 
         Homeservers should prevent the caller from adding a 3PID to their account if it has
         already been added to another user's account on the homeserver.
+
+        {{% boxes/warning %}}
+        Since this endpoint uses UIA, it cannot be used when the access token was obtained
+        via the [OAuth 2.0 API](/client-server-api/#oauth-20-api).
+        {{% /boxes/warning %}}
       operationId: add3PID
       security:
         - accessTokenQuery: []
diff --git a/data/api/client-server/cross_signing.yaml b/data/api/client-server/cross_signing.yaml
index 8f499d23..3878d24c 100644
--- a/data/api/client-server/cross_signing.yaml
+++ b/data/api/client-server/cross_signing.yaml
@@ -26,7 +26,7 @@ paths:
         Publishes cross-signing keys for the user.
 
         This API endpoint uses the [User-Interactive Authentication API](/client-server-api/#user-interactive-authentication-api).
-        
+
         User-Interactive Authentication MUST be performed, except in these cases:
         - there is no existing cross-signing master key uploaded to the homeserver, OR
         - there is an existing cross-signing master key and it exactly matches the
@@ -34,11 +34,16 @@ paths:
           keys provided in the request (self-signing key, user-signing key) they MUST also
           match the existing keys stored on the server. In other words, the request contains
           no new keys.
-        
+
         This allows clients to freely upload one set of keys, but not modify/overwrite keys if
-        they already exist. Allowing clients to upload the same set of keys more than once 
+        they already exist. Allowing clients to upload the same set of keys more than once
         makes this endpoint idempotent in the case where the response is lost over the network,
         which would otherwise cause a UIA challenge upon retry.
+
+        {{% boxes/warning %}}
+        When this endpoint requires UIA, it cannot be used when the access token was obtained
+        via the [OAuth 2.0 API](/client-server-api/#oauth-20-api).
+        {{% /boxes/warning %}}
       operationId: uploadCrossSigningKeys
       security:
         - accessTokenQuery: []
diff --git a/data/api/client-server/device_management.yaml b/data/api/client-server/device_management.yaml
index b2bcb8ce..fe9f5ba4 100644
--- a/data/api/client-server/device_management.yaml
+++ b/data/api/client-server/device_management.yaml
@@ -137,6 +137,11 @@ paths:
         This API endpoint uses the [User-Interactive Authentication API](/client-server-api/#user-interactive-authentication-api).
 
         Deletes the given device, and invalidates any access token associated with it.
+
+        {{% boxes/warning %}}
+        Since this endpoint uses UIA, it cannot be used when the access token was obtained
+        via the [OAuth 2.0 API](/client-server-api/#oauth-20-api).
+        {{% /boxes/warning %}}
       operationId: deleteDevice
       security:
         - accessTokenQuery: []
@@ -189,6 +194,11 @@ paths:
         This API endpoint uses the [User-Interactive Authentication API](/client-server-api/#user-interactive-authentication-api).
 
         Deletes the given devices, and invalidates any access token associated with them.
+
+        {{% boxes/warning %}}
+        Since this endpoint uses UIA, it cannot be used when the access token was obtained
+        via the [OAuth 2.0 API](/client-server-api/#oauth-20-api).
+        {{% /boxes/warning %}}
       operationId: deleteDevices
       security:
         - accessTokenQuery: []