test(cli): preserve standard builds alongside flat mode

libs/cli/langgraph_cli/cli.py

@@ -409,10 +409,11 @@ For production use, requires a license key in env var LANGGRAPH_CLOUD_LICENSE_KE
     help="Custom build command to run from the langgraph.json directory. If not provided, uses default build process.",
 )
 @click.option(
-    "--single-user-layer",
+    "--flat",
+    "single_user_layer",
     is_flag=True,
-    envvar="LANGGRAPH_CLI_SINGLE_USER_LAYER",
-    help="Combine generated Python build steps into one image layer when supported.",
+    envvar="LANGGRAPH_CLI_FLAT",
+    help="Flatten generated Python build steps into one image layer when supported.",
 )
 @click.argument("docker_build_args", nargs=-1, type=click.UNPROCESSED)
 @cli.command(

libs/cli/tests/unit_tests/cli/test_cli.py

@@ -320,6 +320,14 @@ def test_top_level_help_truncates_command_descriptions_to_single_line() -> None:
     assert "[Beta] List LangSmith Deployments." in deploy_list_line
 
 
+def test_build_help_includes_flat_option() -> None:
+    result = CliRunner().invoke(cli, ["build", "--help"])
+
+    assert result.exit_code == 0
+    assert "--flat" in result.output
+    assert "--single-user-layer" not in result.output
+
+
 def test_dev_command_requires_ssl_certfile_and_keyfile_together(tmp_path) -> None:
     config_path = tmp_path / "langgraph.json"
     config_path.write_text(