diff --git a/packages/client/ui-chat/src/client/conversation-nodes/request-prompt.ts b/packages/client/ui-chat/src/client/conversation-nodes/request-prompt.ts
index b974a4bb6b..60b251b478 100644
--- a/packages/client/ui-chat/src/client/conversation-nodes/request-prompt.ts
+++ b/packages/client/ui-chat/src/client/conversation-nodes/request-prompt.ts
@@ -66,7 +66,7 @@ export function systemMessageDefinition(inspect: SystemPromptInspector): Convers
     kind: 'system-message',
     target: 'chat',
     match: event => event.type === 'system/message'
-      || ('surfaceOp' in event && event.surfaceOp !== undefined && event.surfaceOp !== 'append')
+      || ('surfaceOp' in event && event.surfaceOp !== 'append')
       ? { id: String(event.seq), role: 'start' }
       : null,
     start: (_context, match, reader) => {
diff --git a/packages/client/ui-trajectory/src/client/trajectory-request-header-definition.ts b/packages/client/ui-trajectory/src/client/trajectory-request-header-definition.ts
index 130031718e..d8e8a754dc 100644
--- a/packages/client/ui-trajectory/src/client/trajectory-request-header-definition.ts
+++ b/packages/client/ui-trajectory/src/client/trajectory-request-header-definition.ts
@@ -34,7 +34,7 @@ function trajectorySystemMessageDefinition(inspect: SystemPromptInspector): Conv
     kind: 'trajectory-system-message',
     target: 'trajectory',
     match: event => event.type === 'system/message'
-      || ('surfaceOp' in event && event.surfaceOp !== undefined && event.surfaceOp !== 'append')
+      || ('surfaceOp' in event && event.surfaceOp !== 'append')
       ? { id: String(event.seq), role: 'start' }
       : null,
     start: (_context, match, reader) => {