Orquesta Workflow with items

Trying to figure out how to cycle through a huge json to just get the names

not sure why i keep getting groups_stdout is not type list

input:
  - hostname
  - args
  - credential_name
  - cmdlet_credential_name
tasks:
  get_members_in_group:
action: activedirectory.get_ad_group_member hostname=<% ctx(hostname) %> args=<% ctx(args) %> credential_name=<% ctx(credential_name) %> cmdlet_credential_name=<% ctx(cmdlet_credential_name) %> output=json
next:
  - when: <% succeeded() %>
    publish:
      - groups_stdout: <% result() %>
      - stderr: <% result().stderr %>
    do: send_slack_message

  send_slack_message:
with:
  items: name in <% ctx(groups_stdout) %>
action: chatops.post_message
input:
  message: "---"
  #can also work ctx(assignee_email).split('@')[0]
  channel: "#development"
  extra:
    slack:
      attachments:
        - fallback: "Info  %>"
          color: "#00AA00"
          title: "test"
          title_link: "https://www.google.com"
          fields:
            - title: "test"
              value: "<% items(name) %>"
              #value: "<% ctx().groups_stdout.result.stdout %>"
              short: false
next:
  - when: <% succeeded() %>
    publish:
      - message_stdout: <% result() %>

output:
  - groups_stdout: <% ctx().groups_stdout.result.stdout %>
  - items: <% task(get_members_in_group).result.items.select($.result.stdout) %>

groups_stdout is not available inside the with.
groups_stdout needs to be an input