ChatOps acknowledgement context in StackStorm

ack.js

{
  "actionalias": {
    "uid": "action:chatops:get",
    "ack": {
      "format": "Got {{ execution.parameters.thing }}"
    },
    "enabled": true,
    "name": "get",
    "result": {
      "enabled": false
    },
    "formats": [
      "(get|accio|fetch)( (a|my|the))? {{ thing }}(,? (right now|immediately))?[!.]?"
    ],
    "action_ref": "chatops.test",
    "pack": "chatops",
    "ref": "chatops.get",
    "id": "5655efd94f6634729e31c4d8",
    "description": "Gets things"
  },
  "message": "Got tennis ball",
  "execution": {
    "status": "requested",
    "start_timestamp": "2015-11-25T19:49:47.865864Z",
    "parameters": {
      "thing": "tennis ball"
    },
    "runner": {
      "runner_module": "st2actions.runners.pythonrunner",
      "description": "A runner for launching python actions.",
      "enabled": true,
      "runner_parameters": "[Object]",
      "id": "5652fd89cf215c3e2ec6bea4",
      "name": "run-python"
    },
    "context": {
      "action_alias_ref": "[Object]",
      "user": "chatops_bot",
      "api_user": "emedvedev",
      "source_channel": "landofooo"
    },
    "action": {
      "name": "test",
      "runner_type": "run-python",
      "tags": [
        
      ],
      "description": "Post a message to stream for chatops",
      "enabled": true,
      "entry_point": "",
      "uid": "action:chatops:test",
      "parameters": "[Object]",
      "ref": "chatops.test",
      "id": "5655e5b34f66346f278b8d21",
      "pack": "chatops"
    },
    "liveaction": {
      "action": "chatops.test",
      "callback": {
        
      },
      "runner_info": {
        
      },
      "id": "565610db4f6634599cbcc923"
    },
    "id": "565610db4f6634599cbcc924"
  }
}