From b88f377623a0858dcc905800d3593246b8335523 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Mon, 16 Feb 2026 03:23:30 +0100
Subject: [PATCH] fix: make fast-tool stub type portable

---
 src/agents/test-helpers/fast-tool-stubs.ts | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/agents/test-helpers/fast-tool-stubs.ts b/src/agents/test-helpers/fast-tool-stubs.ts
index 8560c9c5b41..da29363b50f 100644
--- a/src/agents/test-helpers/fast-tool-stubs.ts
+++ b/src/agents/test-helpers/fast-tool-stubs.ts
@@ -1,10 +1,18 @@
 import { vi } from "vitest";
 
-export const stubTool = (name: string) => ({
+export type StubTool = {
+  name: string;
+  description: string;
+  parameters: { type: "object"; properties: Record<string, unknown> };
+  // Keep the exported type portable: don't leak Vitest's mock types into .d.ts.
+  execute: (...args: unknown[]) => unknown;
+};
+
+export const stubTool = (name: string): StubTool => ({
   name,
   description: `${name} stub`,
   parameters: { type: "object", properties: {} },
-  execute: vi.fn(),
+  execute: vi.fn() as unknown as (...args: unknown[]) => unknown,
 });
 
 vi.mock("../tools/image-tool.js", () => ({