diff --git a/src/plugin.tsx b/src/plugin.tsx
index 7d9d020..21f156b 100644
--- a/src/plugin.tsx
+++ b/src/plugin.tsx
@@ -31,7 +31,7 @@ export interface ServerAPI {
   callServerMethod<TArgs = {}, TRes = {}>(methodName: string, args: TArgs): Promise<ServerResponse<TRes>>;
   fetchNoCors<TRes = {}>(url: string, request: RequestInfo): Promise<ServerResponse<TRes>>;
   executeInTab(tab: string, runAsync: boolean, code: string): Promise<unknown>;
-  injectCssIntoTab<TRes = boolean>(tab: string, style: string): Promise<ServerResponse<TRes>>;
+  injectCssIntoTab<TRes = string>(tab: string, style: string): Promise<ServerResponse<TRes>>;
   removeCssFromTab(tab: string, cssId: string): Promise<unknown>;
 }