diff --git a/src/gateway/server.sessions.create.test.ts b/src/gateway/server.sessions.create.test.ts
index 4c9f9109f22f..3c769184f60b 100644
--- a/src/gateway/server.sessions.create.test.ts
+++ b/src/gateway/server.sessions.create.test.ts
@@ -5,7 +5,7 @@ import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import { promisify } from "node:util";
-import { afterEach, expect, test, vi } from "vitest";
+import { afterEach, beforeEach, expect, test, vi } from "vitest";
 import { useAutoCleanupTempDirTracker } from "../../test/helpers/temp-dir.js";
 import { findGitCheckoutRoot } from "../agents/worktrees/git.js";
 import {
@@ -57,11 +57,35 @@ import {
   seedSessionTranscript,
 } from "./test/server-sessions.test-helpers.js";
 
+type EnsureSessionDiffBaseline =
+  (typeof import("../sessions/session-diff-baseline.js"))["ensureSessionDiffBaseline"];
+
+const sessionDiffBaselineMocks = vi.hoisted(() => ({
+  ensure: vi.fn<EnsureSessionDiffBaseline>(),
+  useReal: false,
+}));
+
+vi.mock("../sessions/session-diff-baseline.js", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("../sessions/session-diff-baseline.js")>();
+  sessionDiffBaselineMocks.ensure.mockImplementation(async (params) =>
+    sessionDiffBaselineMocks.useReal
+      ? await actual.ensureSessionDiffBaseline(params)
+      : params.entry,
+  );
+  return { ...actual, ensureSessionDiffBaseline: sessionDiffBaselineMocks.ensure };
+});
+
 const { createSessionStoreDir, createSelectedGlobalSessionStore, openClient } =
   setupGatewaySessionsTestHarness();
 const execFileAsync = promisify(execFile);
 const tempDirs = useAutoCleanupTempDirTracker(afterEach);
 
+beforeEach(() => {
+  sessionDiffBaselineMocks.ensure.mockClear();
+  // Baseline capture has dedicated owner coverage and one authenticated integration below.
+  sessionDiffBaselineMocks.useReal = false;
+});
+
 async function makeNonGitTempDir(prefix: string): Promise<string> {
   let root = await fs.realpath(os.tmpdir());
   for (;;) {
@@ -695,6 +719,51 @@ async function initializeGitWorkspace(root: string): Promise<string> {
   return await fs.realpath(workspace);
 }
 
+test("sessions.create captures and persists the initial workspace diff baseline", async () => {
+  const root = tempDirs.make("openclaw-session-diff-baseline-");
+  const workspace = await initializeGitWorkspace(root);
+  await fs.appendFile(path.join(workspace, "README.md"), "dirty at session start\n");
+  const { storePath } = await createSessionStoreDir();
+  sessionDiffBaselineMocks.useReal = true;
+  const { ws } = await openClient({
+    browserOrigin: "http://127.0.0.1",
+    client: {
+      id: GATEWAY_CLIENT_NAMES.CONTROL_UI,
+      version: "dev",
+      platform: "web",
+      mode: GATEWAY_CLIENT_MODES.WEBCHAT,
+    },
+  });
+  try {
+    const created = await rpcReq<{ key?: string; sessionId?: string }>(ws, "sessions.create", {
+      agentId: "main",
+      cwd: workspace,
+    });
+    expect(created.ok, JSON.stringify(created.error)).toBe(true);
+    expect(sessionDiffBaselineMocks.ensure).toHaveBeenCalledTimes(1);
+    const sessionKey = requireNonEmptyString(created.payload?.key, "baseline session key");
+    const sessionId = requireNonEmptyString(created.payload?.sessionId, "baseline session id");
+    expect(loadSessionEntry({ sessionKey, storePath })).toMatchObject({
+      sessionId,
+      spawnedCwd: workspace,
+      sessionDiffBaseline: {
+        version: 1,
+        sessionId,
+        root: workspace,
+        files: [
+          {
+            path: "README.md",
+            fingerprint: expect.any(String),
+          },
+        ],
+      },
+    });
+  } finally {
+    sessionDiffBaselineMocks.useReal = false;
+    ws.close();
+  }
+});
+
 function requireNonEmptyString(value: string | undefined, label: string): string {
   if (!value) {
     throw new Error(`expected ${label}`);