tools: polymer lint gives error as '[object Object]'

 debug:   got args:
{ args: [ 'lint', '--verbose' ] }
debug:   got default config from polymer.json file:
{ config:
   { entrypoint: 'index.html',
     shell: 'src/ant-app.html',
     fragments: [ 'src/ant-config.html', 'src/ant-app.html' ],
     sources: [ 'src/**/*', 'images/**/*', 'bower.json' ],
     extraDependencies:
      [ 'manifest.json',
        'bower_components/webcomponentsjs/webcomponents-lite.min.js',
        'node_modules/redux/dist/redux.min.js' ],
     lint: { rules: [ 'polymer-1' ] } } }
debug:   adding command analyze
debug:   adding command build
debug:   adding command help
debug:   adding command init
debug:   adding command install
debug:   adding command lint
debug:   adding command serve
debug:   adding command test
debug:   running...
debug:   command 'lint' found, parsing command args:
{ args: [ '--verbose' ] }
debug:   command options parsed from args:
{ verbose: true }
debug:   final project configuration generated:
{ lint: { rules: [ 'polymer-1' ] },
  root: '/mnt/c/Users/David/Development/z/antenna/maxw-master',
  entrypoint: '/mnt/c/Users/David/Development/z/antenna/maxw-master/index.html',
  shell: '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html',
  fragments:
   [ '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-config.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html' ],
  extraDependencies:
   [ '/mnt/c/Users/David/Development/z/antenna/maxw-master/manifest.json',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/bower_components/webcomponentsjs/webcomponents-lite.min.js',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/node_modules/redux/dist/redux.min.js',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/bower_components/webcomponentsjs/*.js' ],
  sources:
   [ '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/**/*',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/images/**/*',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/bower.json',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/index.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-config.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html' ],
  allFragments:
   [ '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-config.html',
     '/mnt/c/Users/David/Development/z/antenna/maxw-master/src/ant-app.html' ] }
debug:   Running command...
[object Object]
<ant-config></ant-config>
~~~~~~~~~~~~

index.html(172,4) warning [undefined-elements] - The element ant-config is not defined
<ant-app></ant-app>
~~~~~~~~~

index.html(173,4) warning [undefined-elements] - The element ant-app is not defined
Found  1 errors 2 warnings.
maxw@maxw-master$