From 06aa1dcc3d9636e4592d7493b873b1b5c12cce30 Mon Sep 17 00:00:00 2001
From: Don neumark <don.neumark@gmail.com>
Date: Tue, 30 Jun 2026 04:18:27 +0300
Subject: [PATCH] fix(sandbox-vercel): forward credentials when resuming
 sessions

---
 .changeset/tidy-sandboxes-resume.md           |  5 +++
 .../sandbox-vercel/src/vercel-sandbox.test.ts | 31 +++++++++++++++++--
 packages/sandbox-vercel/src/vercel-sandbox.ts | 26 ++++++++++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/tidy-sandboxes-resume.md

diff --git a/.changeset/tidy-sandboxes-resume.md b/.changeset/tidy-sandboxes-resume.md
new file mode 100644
index 000000000000..0e823dacef74
--- /dev/null
+++ b/.changeset/tidy-sandboxes-resume.md
@@ -0,0 +1,5 @@
+---
+'@ai-sdk/sandbox-vercel': patch
+---
+
+Forward Vercel Sandbox credentials when resuming named harness sessions.
diff --git a/packages/sandbox-vercel/src/vercel-sandbox.test.ts b/packages/sandbox-vercel/src/vercel-sandbox.test.ts
index edf19a41101f..d1af96a93962 100644
--- a/packages/sandbox-vercel/src/vercel-sandbox.test.ts
+++ b/packages/sandbox-vercel/src/vercel-sandbox.test.ts
@@ -2,10 +2,13 @@ import type { Sandbox } from '@vercel/sandbox';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { createVercelSandbox } from './vercel-sandbox';
 
-const { createMock } = vi.hoisted(() => ({ createMock: vi.fn() }));
+const { createMock, getMock } = vi.hoisted(() => ({
+  createMock: vi.fn(),
+  getMock: vi.fn(),
+}));
 
 vi.mock('@vercel/sandbox', () => ({
-  Sandbox: { create: createMock },
+  Sandbox: { create: createMock, get: getMock },
 }));
 
 type MockSpies = {
@@ -222,6 +225,7 @@ describe('createVercelSandbox (wrap existing)', () => {
 describe('createVercelSandbox (create from scratch)', () => {
   beforeEach(() => {
     createMock.mockReset();
+    getMock.mockReset();
   });
 
   it('applies a 30 minute default timeout when none is provided', async () => {
@@ -270,4 +274,27 @@ describe('createVercelSandbox (create from scratch)', () => {
     expect(spies.stop).toHaveBeenCalledTimes(1);
     expect(spies.delete).toHaveBeenCalledTimes(1);
   });
+
+  it('forwards credentials when resuming a named session', async () => {
+    const { sandbox } = makeMockSandbox();
+    getMock.mockResolvedValueOnce(sandbox);
+    const abortController = new AbortController();
+
+    await createVercelSandbox({
+      token: 'token_test',
+      teamId: 'team_test',
+      projectId: 'prj_test',
+    }).resumeSession?.({
+      sessionId: 'session-123',
+      abortSignal: abortController.signal,
+    });
+
+    expect(getMock).toHaveBeenCalledWith({
+      name: 'ai-sdk-harness-session-session-123',
+      token: 'token_test',
+      teamId: 'team_test',
+      projectId: 'prj_test',
+      signal: abortController.signal,
+    });
+  });
 });
diff --git a/packages/sandbox-vercel/src/vercel-sandbox.ts b/packages/sandbox-vercel/src/vercel-sandbox.ts
index 349f0e440999..845fc6d55a71 100644
--- a/packages/sandbox-vercel/src/vercel-sandbox.ts
+++ b/packages/sandbox-vercel/src/vercel-sandbox.ts
@@ -185,6 +185,7 @@ export class VercelSandboxProvider implements HarnessV1SandboxProvider {
         if (resolvedId == null) {
           resolvedId = await pollForTemplateSnapshot(
             templateName,
+            getSandboxLookupParams(baseParams),
             options?.abortSignal,
           );
         }
@@ -228,6 +229,7 @@ export class VercelSandboxProvider implements HarnessV1SandboxProvider {
     }
 
     const sandbox = await Sandbox.get({
+      ...getSandboxLookupParams(this.settings),
       name: sessionSandboxName(options.sessionId),
       ...(options.abortSignal ? { signal: options.abortSignal } : {}),
     });
@@ -250,6 +252,28 @@ const SNAPSHOT_CACHE_KEY = Symbol.for(
 );
 
 type SnapshotCache = Map<string, string>;
+type SandboxLookupParams = {
+  fetch?: typeof fetch;
+  projectId?: string;
+  teamId?: string;
+  token?: string;
+};
+
+function getSandboxLookupParams(
+  settings: VercelSandboxSettings,
+): SandboxLookupParams {
+  if ('sandbox' in settings && settings.sandbox != null) {
+    return {};
+  }
+
+  const { fetch, projectId, teamId, token } = settings as SandboxLookupParams;
+  return {
+    ...(fetch ? { fetch } : {}),
+    ...(projectId ? { projectId } : {}),
+    ...(teamId ? { teamId } : {}),
+    ...(token ? { token } : {}),
+  };
+}
 
 function getSnapshotCache(): SnapshotCache {
   const globals = globalThis as {
@@ -265,12 +289,14 @@ function getSnapshotCache(): SnapshotCache {
 
 async function pollForTemplateSnapshot(
   name: string,
+  lookupParams: ReturnType<typeof getSandboxLookupParams>,
   abortSignal: AbortSignal | undefined,
 ): Promise<string> {
   const deadline = Date.now() + SNAPSHOT_POLL_TIMEOUT_MS;
   while (Date.now() < deadline) {
     abortSignal?.throwIfAborted();
     const refreshed = await Sandbox.get({
+      ...lookupParams,
       name,
       resume: false,
       ...(abortSignal ? { signal: abortSignal } : {}),