diff --git a/extensions/diffs/index.test.ts b/extensions/diffs/index.test.ts
index df0a0a79192..fe7533683ec 100644
--- a/extensions/diffs/index.test.ts
+++ b/extensions/diffs/index.test.ts
@@ -1,6 +1,7 @@
 import type { IncomingMessage } from "node:http";
 import { describe, expect, it, vi } from "vitest";
 import { createMockServerResponse } from "../../src/test-utils/mock-http-response.js";
+import { createTestPluginApi } from "../test-utils/plugin-api.js";
 import plugin from "./index.js";
 
 describe("diffs plugin registration", () => {
@@ -9,33 +10,19 @@ describe("diffs plugin registration", () => {
     const registerHttpRoute = vi.fn();
     const on = vi.fn();
 
-    plugin.register?.({
-      id: "diffs",
-      name: "Diffs",
-      description: "Diffs",
-      source: "test",
-      config: {},
-      runtime: {} as never,
-      logger: {
-        info() {},
-        warn() {},
-        error() {},
-      },
-      registerTool,
-      registerHook() {},
-      registerHttpRoute,
-      registerChannel() {},
-      registerGatewayMethod() {},
-      registerCli() {},
-      registerService() {},
-      registerProvider() {},
-      registerCommand() {},
-      registerContextEngine() {},
-      resolvePath(input: string) {
-        return input;
-      },
-      on,
-    });
+    plugin.register?.(
+      createTestPluginApi({
+        id: "diffs",
+        name: "Diffs",
+        description: "Diffs",
+        source: "test",
+        config: {},
+        runtime: {} as never,
+        registerTool,
+        registerHttpRoute,
+        on,
+      }),
+    );
 
     expect(registerTool).toHaveBeenCalledTimes(1);
     expect(registerHttpRoute).toHaveBeenCalledTimes(1);
@@ -65,53 +52,38 @@ describe("diffs plugin registration", () => {
         ) => Promise<boolean>)
       | undefined;
 
-    plugin.register?.({
-      id: "diffs",
-      name: "Diffs",
-      description: "Diffs",
-      source: "test",
-      config: {
-        gateway: {
-          port: 18789,
-          bind: "loopback",
+    plugin.register?.(
+      createTestPluginApi({
+        id: "diffs",
+        name: "Diffs",
+        description: "Diffs",
+        source: "test",
+        config: {
+          gateway: {
+            port: 18789,
+            bind: "loopback",
+          },
         },
-      },
-      pluginConfig: {
-        defaults: {
-          mode: "view",
-          theme: "light",
-          background: false,
-          layout: "split",
-          showLineNumbers: false,
-          diffIndicators: "classic",
-          lineSpacing: 2,
+        pluginConfig: {
+          defaults: {
+            mode: "view",
+            theme: "light",
+            background: false,
+            layout: "split",
+            showLineNumbers: false,
+            diffIndicators: "classic",
+            lineSpacing: 2,
+          },
         },
-      },
-      runtime: {} as never,
-      logger: {
-        info() {},
-        warn() {},
-        error() {},
-      },
-      registerTool(tool) {
-        registeredTool = typeof tool === "function" ? undefined : tool;
-      },
-      registerHook() {},
-      registerHttpRoute(params) {
-        registeredHttpRouteHandler = params.handler as typeof registeredHttpRouteHandler;
-      },
-      registerChannel() {},
-      registerGatewayMethod() {},
-      registerCli() {},
-      registerService() {},
-      registerProvider() {},
-      registerCommand() {},
-      registerContextEngine() {},
-      resolvePath(input: string) {
-        return input;
-      },
-      on() {},
-    });
+        runtime: {} as never,
+        registerTool(tool) {
+          registeredTool = typeof tool === "function" ? undefined : tool;
+        },
+        registerHttpRoute(params) {
+          registeredHttpRouteHandler = params.handler as typeof registeredHttpRouteHandler;
+        },
+      }),
+    );
 
     const result = await registeredTool?.execute?.("tool-1", {
       before: "one\n",
diff --git a/extensions/diffs/src/tool.test.ts b/extensions/diffs/src/tool.test.ts
index 210586ad381..056b10c0643 100644
--- a/extensions/diffs/src/tool.test.ts
+++ b/extensions/diffs/src/tool.test.ts
@@ -2,6 +2,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import type { OpenClawPluginApi } from "openclaw/plugin-sdk/diffs";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { createTestPluginApi } from "../../test-utils/plugin-api.js";
 import type { DiffScreenshotter } from "./browser.js";
 import { DEFAULT_DIFFS_TOOL_DEFAULTS } from "./config.js";
 import { DiffArtifactStore } from "./store.js";
@@ -383,7 +384,7 @@ describe("diffs tool", () => {
 });
 
 function createApi(): OpenClawPluginApi {
-  return {
+  return createTestPluginApi({
     id: "diffs",
     name: "Diffs",
     description: "Diffs",
@@ -395,26 +396,7 @@ function createApi(): OpenClawPluginApi {
       },
     },
     runtime: {} as OpenClawPluginApi["runtime"],
-    logger: {
-      info() {},
-      warn() {},
-      error() {},
-    },
-    registerTool() {},
-    registerHook() {},
-    registerHttpRoute() {},
-    registerChannel() {},
-    registerGatewayMethod() {},
-    registerCli() {},
-    registerService() {},
-    registerProvider() {},
-    registerCommand() {},
-    registerContextEngine() {},
-    resolvePath(input: string) {
-      return input;
-    },
-    on() {},
-  };
+  }) as OpenClawPluginApi;
 }
 
 function createToolWithScreenshotter(
diff --git a/extensions/phone-control/index.test.ts b/extensions/phone-control/index.test.ts
index 9259092b153..2c3462c82a9 100644
--- a/extensions/phone-control/index.test.ts
+++ b/extensions/phone-control/index.test.ts
@@ -7,6 +7,7 @@ import type {
   PluginCommandContext,
 } from "openclaw/plugin-sdk/phone-control";
 import { describe, expect, it, vi } from "vitest";
+import { createTestPluginApi } from "../test-utils/plugin-api.js";
 import registerPhoneControl from "./index.js";
 
 function createApi(params: {
@@ -15,7 +16,7 @@ function createApi(params: {
   writeConfig: (next: Record<string, unknown>) => Promise<void>;
   registerCommand: (command: OpenClawPluginCommandDefinition) => void;
 }): OpenClawPluginApi {
-  return {
+  return createTestPluginApi({
     id: "phone-control",
     name: "phone-control",
     source: "test",
@@ -30,22 +31,8 @@ function createApi(params: {
         writeConfigFile: (next: Record<string, unknown>) => params.writeConfig(next),
       },
     } as OpenClawPluginApi["runtime"],
-    logger: { info() {}, warn() {}, error() {} },
-    registerTool() {},
-    registerHook() {},
-    registerHttpRoute() {},
-    registerChannel() {},
-    registerGatewayMethod() {},
-    registerCli() {},
-    registerService() {},
-    registerProvider() {},
-    registerContextEngine() {},
     registerCommand: params.registerCommand,
-    resolvePath(input: string) {
-      return input;
-    },
-    on() {},
-  };
+  }) as OpenClawPluginApi;
 }
 
 function createCommandContext(args: string): PluginCommandContext {
diff --git a/extensions/test-utils/plugin-api.ts b/extensions/test-utils/plugin-api.ts
new file mode 100644
index 00000000000..4f28d86c490
--- /dev/null
+++ b/extensions/test-utils/plugin-api.ts
@@ -0,0 +1,43 @@
+type TestLogger = {
+  info: () => void;
+  warn: () => void;
+  error: () => void;
+  debug?: () => void;
+};
+
+type TestPluginApiDefaults = {
+  logger: TestLogger;
+  registerTool: () => void;
+  registerHook: () => void;
+  registerHttpRoute: () => void;
+  registerChannel: () => void;
+  registerGatewayMethod: () => void;
+  registerCli: () => void;
+  registerService: () => void;
+  registerProvider: () => void;
+  registerCommand: () => void;
+  registerContextEngine: () => void;
+  resolvePath: (input: string) => string;
+  on: () => void;
+};
+
+export function createTestPluginApi<T extends object>(api: T): T & TestPluginApiDefaults {
+  return {
+    logger: { info() {}, warn() {}, error() {} },
+    registerTool() {},
+    registerHook() {},
+    registerHttpRoute() {},
+    registerChannel() {},
+    registerGatewayMethod() {},
+    registerCli() {},
+    registerService() {},
+    registerProvider() {},
+    registerCommand() {},
+    registerContextEngine() {},
+    resolvePath(input: string) {
+      return input;
+    },
+    on() {},
+    ...api,
+  };
+}