diff --git a/extensions/diffs/index.ts b/extensions/diffs/index.ts
index fd3fb0d29a6..eb28fc00387 100644
--- a/extensions/diffs/index.ts
+++ b/extensions/diffs/index.ts
@@ -1,54 +1,11 @@
-import path from "node:path";
-import {
-  definePluginEntry,
-  resolvePreferredOpenClawTmpDir,
-  type OpenClawPluginApi,
-} from "./api.js";
-import {
-  diffsPluginConfigSchema,
-  resolveDiffsPluginDefaults,
-  resolveDiffsPluginSecurity,
-  resolveDiffsPluginViewerBaseUrl,
-} from "./src/config.js";
-import { createDiffsHttpHandler } from "./src/http.js";
-import { DIFFS_AGENT_GUIDANCE } from "./src/prompt-guidance.js";
-import { DiffArtifactStore } from "./src/store.js";
-import { createDiffsTool } from "./src/tool.js";
+import { definePluginEntry } from "./api.js";
+import { diffsPluginConfigSchema } from "./src/config.js";
+import { registerDiffsPlugin } from "./src/plugin.js";
 
 export default definePluginEntry({
   id: "diffs",
   name: "Diffs",
   description: "Read-only diff viewer and PNG/PDF renderer for agents.",
   configSchema: diffsPluginConfigSchema,
-  register(api: OpenClawPluginApi) {
-    const defaults = resolveDiffsPluginDefaults(api.pluginConfig);
-    const security = resolveDiffsPluginSecurity(api.pluginConfig);
-    const viewerBaseUrl = resolveDiffsPluginViewerBaseUrl(api.pluginConfig);
-    const store = new DiffArtifactStore({
-      rootDir: path.join(resolvePreferredOpenClawTmpDir(), "openclaw-diffs"),
-      logger: api.logger,
-    });
-
-    api.registerTool(
-      (ctx) => createDiffsTool({ api, store, defaults, viewerBaseUrl, context: ctx }),
-      {
-        name: "diffs",
-      },
-    );
-    api.registerHttpRoute({
-      path: "/plugins/diffs",
-      auth: "plugin",
-      match: "prefix",
-      handler: createDiffsHttpHandler({
-        store,
-        logger: api.logger,
-        allowRemoteViewer: security.allowRemoteViewer,
-        trustedProxies: api.config.gateway?.trustedProxies,
-        allowRealIpFallback: api.config.gateway?.allowRealIpFallback === true,
-      }),
-    });
-    api.on("before_prompt_build", async () => ({
-      prependSystemContext: DIFFS_AGENT_GUIDANCE,
-    }));
-  },
+  register: registerDiffsPlugin,
 });
diff --git a/extensions/diffs/src/browser.test.ts b/extensions/diffs/src/browser.test.ts
index c522808fbb3..9db46f202e8 100644
--- a/extensions/diffs/src/browser.test.ts
+++ b/extensions/diffs/src/browser.test.ts
@@ -6,7 +6,7 @@ import { createMockServerResponse } from "../../../test/helpers/plugins/mock-htt
 import { createTestPluginApi } from "../../../test/helpers/plugins/plugin-api.js";
 import type { OpenClawConfig } from "../api.js";
 import type { OpenClawPluginApi, OpenClawPluginToolContext } from "../api.js";
-import plugin from "../index.js";
+import { registerDiffsPlugin } from "./plugin.js";
 import { createTempDiffRoot } from "./test-helpers.js";
 
 const { launchMock } = vi.hoisted(() => ({
@@ -239,7 +239,7 @@ describe("diffs plugin registration", () => {
       on,
     });
 
-    plugin.register?.(api as unknown as OpenClawPluginApi);
+    registerDiffsPlugin(api as unknown as OpenClawPluginApi);
 
     expect(on).toHaveBeenCalledTimes(1);
     expect(on.mock.calls[0]?.[0]).toBe("before_prompt_build");
diff --git a/extensions/diffs/src/plugin.ts b/extensions/diffs/src/plugin.ts
new file mode 100644
index 00000000000..7cb7ec7fa0f
--- /dev/null
+++ b/extensions/diffs/src/plugin.ts
@@ -0,0 +1,43 @@
+import path from "node:path";
+import { resolvePreferredOpenClawTmpDir, type OpenClawPluginApi } from "../api.js";
+import {
+  resolveDiffsPluginDefaults,
+  resolveDiffsPluginSecurity,
+  resolveDiffsPluginViewerBaseUrl,
+} from "./config.js";
+import { createDiffsHttpHandler } from "./http.js";
+import { DIFFS_AGENT_GUIDANCE } from "./prompt-guidance.js";
+import { DiffArtifactStore } from "./store.js";
+import { createDiffsTool } from "./tool.js";
+
+export function registerDiffsPlugin(api: OpenClawPluginApi): void {
+  const defaults = resolveDiffsPluginDefaults(api.pluginConfig);
+  const security = resolveDiffsPluginSecurity(api.pluginConfig);
+  const viewerBaseUrl = resolveDiffsPluginViewerBaseUrl(api.pluginConfig);
+  const store = new DiffArtifactStore({
+    rootDir: path.join(resolvePreferredOpenClawTmpDir(), "openclaw-diffs"),
+    logger: api.logger,
+  });
+
+  api.registerTool(
+    (ctx) => createDiffsTool({ api, store, defaults, viewerBaseUrl, context: ctx }),
+    {
+      name: "diffs",
+    },
+  );
+  api.registerHttpRoute({
+    path: "/plugins/diffs",
+    auth: "plugin",
+    match: "prefix",
+    handler: createDiffsHttpHandler({
+      store,
+      logger: api.logger,
+      allowRemoteViewer: security.allowRemoteViewer,
+      trustedProxies: api.config.gateway?.trustedProxies,
+      allowRealIpFallback: api.config.gateway?.allowRealIpFallback === true,
+    }),
+  });
+  api.on("before_prompt_build", async () => ({
+    prependSystemContext: DIFFS_AGENT_GUIDANCE,
+  }));
+}