diff --git a/src/langbot/pkg/box/workspace.py b/src/langbot/pkg/box/workspace.py
index 41fca039..2f4b03ed 100644
--- a/src/langbot/pkg/box/workspace.py
+++ b/src/langbot/pkg/box/workspace.py
@@ -157,6 +157,12 @@ def wrap_python_command_with_env(command: str, *, mount_path: str = '/workspace'
         export TMP="$_LB_TMP_DIR"
         export PIP_CACHE_DIR="$_LB_PIP_CACHE_DIR"
 
+        _LB_SYSTEM_PYTHON="$(command -v python3 || command -v python || true)"
+        if [ -z "$_LB_SYSTEM_PYTHON" ]; then
+          echo "No Python interpreter found for workspace bootstrap" >&2
+          exit 1
+        fi
+
         _lb_python_meta() {{
           "$_LB_SYSTEM_PYTHON" - <<'PY'
         import hashlib
diff --git a/tests/unit_tests/provider/test_mcp_box_integration.py b/tests/unit_tests/provider/test_mcp_box_integration.py
index db1aa542..c7e080c0 100644
--- a/tests/unit_tests/provider/test_mcp_box_integration.py
+++ b/tests/unit_tests/provider/test_mcp_box_integration.py
@@ -509,7 +509,8 @@ class TestPythonWorkspacePreparation:
         )
 
         assert command is not None
-        assert 'python -m venv "$_LB_VENV_DIR"' in command
+        assert '_LB_SYSTEM_PYTHON="$(command -v python3 || command -v python || true)"' in command
+        assert '"$_LB_SYSTEM_PYTHON" -m venv "$_LB_VENV_DIR"' in command
         assert 'python -m pip install -r "/workspace/.mcp/u1/workspace/requirements.txt"' in command
         assert 'pip install --no-cache-dir -r' not in command
 
diff --git a/tests/unit_tests/provider/test_skill_tools.py b/tests/unit_tests/provider/test_skill_tools.py
index 96316ee5..7a9cde66 100644
--- a/tests/unit_tests/provider/test_skill_tools.py
+++ b/tests/unit_tests/provider/test_skill_tools.py
@@ -245,7 +245,8 @@ class TestSkillPathHelpers:
 
         command = wrap_skill_command_with_python_env('python scripts/run.py')
 
-        assert 'python -m venv "$_LB_VENV_DIR"' in command
+        assert '_LB_SYSTEM_PYTHON="$(command -v python3 || command -v python || true)"' in command
+        assert '"$_LB_SYSTEM_PYTHON" -m venv "$_LB_VENV_DIR"' in command
         assert 'export VIRTUAL_ENV="$_LB_VENV_DIR"' in command
         assert command.rstrip().endswith('python scripts/run.py')