diff --git a/README.md b/README.md
index 429cdce360..2c9f562949 100644
--- a/README.md
+++ b/README.md
@@ -471,6 +471,7 @@ such a checkout, use `bash ./scripts/<name>.sh ...`.
    make setup-sandbox
    ```
    Reads the configured sandbox image from UTF-8 `config.yaml`, with or without a leading BOM, using LF or CRLF line endings.
+   On macOS, a successful Apple Container pull completes this step even when Docker is not installed. If Docker is available, its image is also pulled.
 
 4. **Start services**:
    ```bash
diff --git a/backend/tests/test_setup_sandbox.py b/backend/tests/test_setup_sandbox.py
index caab50078f..5ba7ea84ab 100644
--- a/backend/tests/test_setup_sandbox.py
+++ b/backend/tests/test_setup_sandbox.py
@@ -1,6 +1,7 @@
 """Regression coverage for sandbox image selection before pulling."""
 
 import os
+import shutil
 import subprocess
 from pathlib import Path
 
@@ -43,3 +44,59 @@ def test_setup_sandbox_image_selection(tmp_path, encoding, configured, newline):
     else:
         assert args[1] != image
         assert f"Using default image: {args[1]}" in result.stdout
+
+
+@pytest.mark.skipif(os.name == "nt", reason="isolated POSIX PATH simulates macOS runtime discovery")
+@pytest.mark.parametrize(
+    ("apple_exit", "docker_available", "configured", "expected_exit", "expected_engines"),
+    [
+        pytest.param(0, False, True, 0, ["container"], id="apple-only-success"),
+        pytest.param(0, False, False, 0, ["container"], id="apple-only-default-image-note"),
+        pytest.param(1, True, True, 0, ["container", "docker"], id="apple-failure-docker-fallback"),
+        pytest.param(None, False, True, 1, [], id="no-engines"),
+        pytest.param(0, True, True, 0, ["container", "docker"], id="both-engines"),
+    ],
+)
+def test_setup_sandbox_runtime_selection(tmp_path, apple_exit, docker_available, configured, expected_exit, expected_engines):
+    bin_dir = tmp_path / "bin"
+    bin_dir.mkdir()
+    # Do not inherit the host PATH: an installed Docker must not mask the bug
+    # or be invoked by a test. All engine commands below are local stubs.
+    (bin_dir / "bash").symlink_to(BASH)
+    for tool in ("sed", "grep", "awk", "head"):
+        executable = shutil.which(tool)
+        if executable is None:
+            pytest.skip(f"shell-script test requires {tool}")
+        (bin_dir / tool).symlink_to(executable)
+    scripts = {"uname": "#!/usr/bin/env bash\nprintf 'Darwin\\n'\n"}
+    if apple_exit is not None:
+        scripts["container"] = f'#!/usr/bin/env bash\nprintf "%s\\n" container "$@" >> "$CAPTURE_ENGINE_ARGS"\nexit {apple_exit}\n'
+    if docker_available:
+        scripts["docker"] = '#!/usr/bin/env bash\nprintf "%s\\n" docker "$@" >> "$CAPTURE_ENGINE_ARGS"\n'
+    for name, script in scripts.items():
+        path = bin_dir / name
+        path.write_text(script, encoding="utf-8")
+        path.chmod(0o755)
+
+    image = "example.invalid/custom-sandbox:review"
+    if configured:
+        (tmp_path / "config.yaml").write_text(f"sandbox:\n  image: {image}\n", encoding="utf-8")
+    else:
+        image = "enterprise-public-cn-beijing.cr.volces.com/vefaas-public/all-in-one-sandbox:1.11.0"
+    capture = tmp_path / "engine-args.txt"
+    env = {**os.environ, "PATH": str(bin_dir), "CAPTURE_ENGINE_ARGS": str(capture)}
+    result = subprocess.run([BASH, str(REPO_ROOT / "scripts/setup-sandbox.sh")], cwd=tmp_path, env=env, capture_output=True, text=True, check=False)
+
+    assert result.returncode == expected_exit, result.stdout + result.stderr
+    args = capture.read_text(encoding="utf-8").splitlines() if capture.exists() else []
+    expected_args = []
+    for engine in expected_engines:
+        expected_args.extend([engine, "image", "pull", image] if engine == "container" else [engine, "pull", image])
+    assert args == expected_args
+    if expected_exit == 0:
+        assert "Sandbox image pulled successfully" in result.stdout
+        assert "Neither Docker nor Apple Container is available" not in result.stdout
+    else:
+        assert "Neither Docker nor Apple Container is available" in result.stdout
+    if not configured:
+        assert "NOTE: pulling this image does not make the sandbox use it." in result.stdout
diff --git a/scripts/AGENTS.md b/scripts/AGENTS.md
index f4f20c6d7f..122447bb4b 100644
--- a/scripts/AGENTS.md
+++ b/scripts/AGENTS.md
@@ -8,6 +8,10 @@ because it runs before dependency synchronization. Read UTF-8 config files
 with or without a leading BOM so the first section remains detectable.
 `setup-sandbox.sh` also strips the leading BOM and normalizes CRLF before selecting the image;
 keep its shell filter compatible with GNU and BSD sed.
+An Apple Container pull that succeeds on macOS must not fail the setup step
+just because Docker is absent. Keep the Docker pull when Docker is available,
+including after an Apple Container failure, and retain the final image-config
+note rather than exiting early on Apple Container success.
 
 The root `PORT` value configures Docker's published nginx ingress only; local
 orchestration pins Next.js to `3000`. Runtime commands launch from the already
diff --git a/scripts/setup-sandbox.sh b/scripts/setup-sandbox.sh
index 9c13813936..a664760dfc 100755
--- a/scripts/setup-sandbox.sh
+++ b/scripts/setup-sandbox.sh
@@ -31,9 +31,15 @@ fi
 
 echo ""
 
+APPLE_PULL_SUCCEEDED=0
 if command -v container >/dev/null 2>&1 && [ "$(uname)" = "Darwin" ]; then
     echo "Detected Apple Container on macOS, pulling image..."
-    container image pull "$IMAGE" || echo "⚠ Apple Container pull failed, will try Docker"
+    if container image pull "$IMAGE"; then
+        APPLE_PULL_SUCCEEDED=1
+        echo "✓ Sandbox image pulled successfully using Apple Container"
+    else
+        echo "⚠ Apple Container pull failed, will try Docker"
+    fi
 fi
 
 if command -v docker >/dev/null 2>&1; then
@@ -45,7 +51,7 @@ if command -v docker >/dev/null 2>&1; then
         echo ""
         echo "⚠ Failed to pull sandbox image (this is OK for local sandbox mode)"
     fi
-else
+elif [ "$APPLE_PULL_SUCCEEDED" -eq 0 ]; then
     echo "✗ Neither Docker nor Apple Container is available"
     echo "  Please install Docker: https://docs.docker.com/get-docker/"
     exit 1