curl --request GET \
  --url https://production.runalloy.com/connectors/{connectorId}/actions/{actionId} \
  --header 'Authorization: Bearer <token>' \
  --header 'x-api-version: <x-api-version>'

{
  "action": {
    "id": "chat_postMessage",
    "displayName": "Post",
    "description": "Posts a message into a channel.",
    "httpMethod": "post",
    "path": "/chat.postMessage",
    "parameters": [
      {
        "name": "token",
        "in": "header",
        "description": "Authentication token. Requires scope: `chat:write`",
        "required": true,
        "schema": {
          "type": "string"
        }
      }
    ],
    "requestBody": {
      "required": [
        "channel",
        "text"
      ],
      "type": "object",
      "properties": {
        "as_user": {
          "type": "string",
          "description": "Pass true to post the message as the authed user, instead of as a bot. Defaults to false. See [authorship](#authorship) below."
        },
        "attachments": {
          "type": "string",
          "description": "A JSON-based array of structured attachments, presented as a URL-encoded string."
        },
        "blocks": {
          "title": "Block Kit blocks",
          "type": "array",
          "description": "This is a very loose definition, in the future, we'll populate this with deeper schema in this definition namespace.",
          "items": {
            "required": [
              "type"
            ],
            "type": "object",
            "properties": {
              "type": {
                "type": "string"
              }
            }
          }
        },
        "channel": {
          "type": "string",
          "description": "Channel, private group, or IM channel to send message to. Can be an encoded ID, or a name. See [below](#channels) for more details."
        },
        "icon_emoji": {
          "type": "string",
          "description": "Emoji to use as the icon for this message. Overrides `icon_url`. Must be used in conjunction with `as_user` set to `false`, otherwise ignored. See [authorship](#authorship) below."
        },
        "icon_url": {
          "type": "string",
          "description": "URL to an image to use as the icon for this message. Must be used in conjunction with `as_user` set to false, otherwise ignored. See [authorship](#authorship) below."
        },
        "link_names": {
          "type": "boolean",
          "description": "Find and link channel names and usernames."
        },
        "mrkdwn": {
          "type": "boolean",
          "description": "Disable Slack markup parsing by setting to `false`. Enabled by default."
        },
        "parse": {
          "type": "string",
          "description": "Change how messages are treated. Defaults to `none`. See [below](#formatting)."
        },
        "reply_broadcast": {
          "type": "boolean",
          "description": "Used in conjunction with `thread_ts` and indicates whether reply should be made visible to everyone in the channel or conversation. Defaults to `false`."
        },
        "text": {
          "type": "string",
          "description": "How this field works and whether it is required depends on other fields you use in your API call. [See below](#text_usage) for more detail."
        },
        "thread_ts": {
          "type": "string",
          "description": "Provide another message's `ts` value to make this message a reply. Avoid using a reply's `ts` value; use its parent instead."
        },
        "unfurl_links": {
          "type": "boolean",
          "description": "Pass true to enable unfurling of primarily text-based content."
        },
        "unfurl_media": {
          "type": "boolean",
          "description": "Pass false to disable unfurling of media content."
        },
        "username": {
          "type": "string",
          "description": "Set your bot's user name. Must be used in conjunction with `as_user` set to false, otherwise ignored. See [authorship](#authorship) below."
        }
      }
    },
    "sampleSuccessResponse": {
      "ok": true,
      "channel": "C1H9RESGL",
      "ts": "1503435956.000247",
      "message": {
        "text": "Here's a message for you",
        "username": "ecto1",
        "bot_id": "B19LU7CSY",
        "attachments": [
          {
            "text": "This is an attachment",
            "id": 1,
            "fallback": "This is an attachment's fallback"
          }
        ],
        "type": "message",
        "subtype": "bot_message",
        "ts": "1503435956.000247"
      }
    }
  }
}