ultracode is different to ultrathink (because of course it is...)
ultrathink was "throw more tokens" (it was a Claude feature that has gone away[1])
ultracode is "throw more tokens AND write code that creates and orchastrates subagents": https://code.claude.com/docs/en/workflows
[1] https://claudelog.com/faqs/what-is-ultrathink/ claims it has returned, but that might not be accurate