hook_context_default_contexts() ?
Here's the piece I was missing:

/**
 * Implementation hook_ctools_plugin_api().
 *
 * Makes module compatible with context 3.
 */
function MY_MODULE_ctools_plugin_api($module, $api) {
  if ($module == 'context' &amp;&amp; ($api == 'plugins' || $api == 'context')) {
    return array('version' =&gt; 3);
  }
}