diff --git a/src/app/api/openrouter/[...path]/route.ts b/src/app/api/openrouter/[...path]/route.ts
index 6b3497bac0..75d693b1d9 100644
--- a/src/app/api/openrouter/[...path]/route.ts
+++ b/src/app/api/openrouter/[...path]/route.ts
@@ -346,7 +346,11 @@ export async function POST(request: NextRequest): Promise<NextResponseType<unkno
     taskId
   );
   if (!provider.supportedChatApis.includes(requestBodyParsed.kind)) {
-    return apiKindNotSupportedResponse(requestBodyParsed.kind, provider.supportedChatApis);
+    return apiKindNotSupportedResponse(
+      requestBodyParsed.kind,
+      provider.supportedChatApis,
+      fraudHeaders
+    );
   }
 
   console.debug(`Routing request to ${provider.id}`);
diff --git a/src/lib/llm-proxy-helpers.ts b/src/lib/llm-proxy-helpers.ts
index ea01bc8d01..743158afac 100644
--- a/src/lib/llm-proxy-helpers.ts
+++ b/src/lib/llm-proxy-helpers.ts
@@ -120,9 +120,12 @@ export function dataCollectionRequiredResponse() {
 
 export function apiKindNotSupportedResponse(
   apiKind: GatewayChatApiKind,
-  supportedApiKinds: ReadonlyArray<GatewayChatApiKind>
+  supportedApiKinds: ReadonlyArray<GatewayChatApiKind>,
+  fraudHeaders: FraudDetectionHeaders
 ) {
-  const error = `This model does not support the ${apiKind} API, please use any of: ${supportedApiKinds.join()}`;
+  const error = isRooCodeBasedClient(fraudHeaders)
+    ? 'This model requires Kilo v7 or newer. Please upgrade Kilo and try again.'
+    : `This model does not support the ${apiKind} API, please use any of: ${supportedApiKinds.join()}`;
   return NextResponse.json({ error, message: error }, { status: 400 });
 }