diff --git a/src/config/types.ts b/src/config/types.ts
index 991141e7..21d6e48d 100644
--- a/src/config/types.ts
+++ b/src/config/types.ts
@@ -1,6 +1,6 @@
 import type { BrowserConfig } from "./browser-config";
 import type { BrowserTestRunEnvOptions } from "../runner/browser-env/vite/types";
-import type { Suite, Test } from "../types";
+import type { Test } from "../types";
 import type { ChildProcessWithoutNullStreams } from "child_process";
 import { RequestOptions } from "https";
 
@@ -215,7 +215,7 @@ export interface MochaOpts {
     isWorker?: boolean;
 
     /** Interface name or path to file with custom interface implementation. */
-    ui?: string | Suite;
+    ui?: string | ((suite: unknown) => void);
 }
 
 export interface SystemConfig {