Removing a key from parent object with jq

I believe your original attempt should have worked as expected. Here is what I get when I try it:

$ jq 'del(.pages)' myfile.json
{
  "actions": {
    "pages": {
      "stuff": "..."
    }
  }
}

Try it online at jqplay.org

To remove all pages everywhere you would need something like

$ jq 'del(.. | .pages?)' myfile.json
{
  "actions": {}
}

Try it online at jqplay.org