diff --git a/src/agents/extensions/sandbox/daytona/sandbox.py b/src/agents/extensions/sandbox/daytona/sandbox.py
index c28645769d..3e8c7ef9a5 100644
--- a/src/agents/extensions/sandbox/daytona/sandbox.py
+++ b/src/agents/extensions/sandbox/daytona/sandbox.py
@@ -35,6 +35,7 @@
     WorkspaceArchiveReadError,
     WorkspaceArchiveWriteError,
     WorkspaceReadNotFoundError,
+    WorkspaceStartError,
     WorkspaceWriteTypeError,
 )
 from ....sandbox.manifest import Manifest
@@ -361,6 +362,33 @@ async def _validate_path_access(self, path: Path | str, *, for_write: bool = Fal
     def _runtime_helpers(self) -> tuple[RuntimeHelperScript, ...]:
         return (RESOLVE_WORKSPACE_PATH_HELPER,)
 
+    async def _prepare_workspace_root(self) -> None:
+        """Create the workspace root before SDK exec calls use it as cwd."""
+        root = Path(self.state.manifest.root)
+        try:
+            envs = await self._resolved_envs()
+            result = await self._sandbox.process.exec(
+                f"mkdir -p -- {shlex.quote(str(root))}",
+                env=envs or None,
+                timeout=self.state.timeouts.fast_op_s,
+            )
+        except Exception as e:
+            raise WorkspaceStartError(path=root, cause=e) from e
+
+        exit_code = int(getattr(result, "exit_code", 0) or 0)
+        if exit_code != 0:
+            raise WorkspaceStartError(
+                path=root,
+                context={
+                    "reason": "workspace_root_nonzero_exit",
+                    "exit_code": exit_code,
+                    "output": str(getattr(result, "result", "") or ""),
+                },
+            )
+
+    async def _prepare_backend_workspace(self) -> None:
+        await self._prepare_workspace_root()
+
     async def mkdir(
         self,
         path: Path | str,
diff --git a/tests/extensions/test_sandbox_daytona.py b/tests/extensions/test_sandbox_daytona.py
index 9bb3d9415c..b9d0175770 100644
--- a/tests/extensions/test_sandbox_daytona.py
+++ b/tests/extensions/test_sandbox_daytona.py
@@ -117,9 +117,14 @@ def __init__(self) -> None:
         self._pty_handles: dict[str, _FakePtyHandle] = {}
         self.create_pty_session_error: BaseException | None = None
         self.symlinks: dict[str, str] = {}
+        self.workspace_roots: set[str] = set()
+        self.require_workspace_root_for_cd = False
 
     async def exec(self, cmd: str, **kwargs: object) -> _FakeExecResult:
         self.exec_calls.append((cmd, dict(kwargs)))
+        parts = shlex.split(cmd)
+        if len(parts) >= 4 and parts[:3] == ["mkdir", "-p", "--"]:
+            self.workspace_roots.add(parts[3])
         if "sleep 0.5" in cmd:
             await asyncio.sleep(0.5)
         result = self.next_result
@@ -150,6 +155,21 @@ async def execute_session_command(
     ) -> object:
         self.execute_session_command_calls.append((session_id, request, dict(kwargs)))
         command = cast(str, getattr(request, "command", ""))
+        parts = shlex.split(command)
+        if (
+            self.require_workspace_root_for_cd
+            and len(parts) >= 3
+            and parts[0] == "cd"
+            and parts[2] == "&&"
+            and parts[1] not in self.workspace_roots
+        ):
+            return types.SimpleNamespace(
+                cmd_id="cmd-123",
+                exit_code=1,
+                stdout="",
+                stderr=f"cd: no such file or directory: {parts[1]}",
+                output=f"cd: no such file or directory: {parts[1]}",
+            )
         resolved = resolve_fake_workspace_path(
             command,
             symlinks=self.symlinks,
@@ -511,6 +531,58 @@ async def test_create_uses_daytona_safe_default_workspace_root(
 
         assert session.state.manifest.root == daytona_module.DEFAULT_DAYTONA_WORKSPACE_ROOT
 
+    @pytest.mark.asyncio
+    async def test_start_prepares_workspace_root_before_runtime_helpers(
+        self,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        """Verify Daytona creates the root before exec uses it as cwd."""
+
+        daytona_module = _load_daytona_module(monkeypatch)
+
+        async with daytona_module.DaytonaSandboxClient() as client:
+            session = await client.create(options=daytona_module.DaytonaSandboxClientOptions())
+            sandbox = _FakeAsyncDaytona.current_sandbox
+            assert sandbox is not None
+            sandbox.process.require_workspace_root_for_cd = True
+
+            await session.start()
+
+        root = daytona_module.DEFAULT_DAYTONA_WORKSPACE_ROOT
+        assert root in sandbox.process.workspace_roots
+        assert sandbox.process.exec_calls[0][0] == f"mkdir -p -- {root}"
+        assert sandbox.process.execute_session_command_calls
+        _session_id, request, _kwargs = sandbox.process.execute_session_command_calls[0]
+        assert cast(str, cast(Any, request).command).startswith(f"cd {root} && ")
+        assert session.state.workspace_root_ready is True
+
+    @pytest.mark.asyncio
+    async def test_start_wraps_workspace_root_prepare_failure(
+        self,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        """Verify Daytona surfaces root preparation failures as start errors."""
+
+        daytona_module = _load_daytona_module(monkeypatch)
+
+        async with daytona_module.DaytonaSandboxClient() as client:
+            session = await client.create(options=daytona_module.DaytonaSandboxClientOptions())
+            sandbox = _FakeAsyncDaytona.current_sandbox
+            assert sandbox is not None
+            sandbox.process.next_result = _FakeExecResult(exit_code=2, result="mkdir failed")
+
+            with pytest.raises(daytona_module.WorkspaceStartError) as exc_info:
+                await session.start()
+
+        assert exc_info.value.context == {
+            "path": daytona_module.DEFAULT_DAYTONA_WORKSPACE_ROOT,
+            "reason": "workspace_root_nonzero_exit",
+            "exit_code": 2,
+            "output": "mkdir failed",
+        }
+        assert sandbox.process.execute_session_command_calls == []
+        assert session.state.workspace_root_ready is False
+
     @pytest.mark.asyncio
     async def test_create_passes_only_option_env_vars_to_daytona(
         self,