Can Otto run on Grok, ChatGPT or Gemini instead of Claude?

Short answer: Grok is not one of the assistants Booked Solid can run on, and there is no way to add it. This article shows you the list that does exist, what happens when you pick something other than the recommended one, and the setting that actually lowers what a working day costs you.

Where the list lives

1. Look at the top bar of the app and open Advanced.
2. The first box is Assistant. The second is Thoroughness.

The Assistant list holds four names and no others:

• Claude Code (recommended)
• ChatGPT (Codex CLI)
• Gemini CLI
• Local AI (Ollama)

Grok is not on that list. Nothing you can install or paste in will put it there.

Why ChatGPT and Gemini are on the list but cannot run Otto

Look closely at those two lines in the picker and you will see they are labelled can't run Otto yet. That label is doing real work. Otto only touches your business through this app's own safety checks: the autonomy dial, the rule that a client email stays a draft until you say otherwise, and the limits on which files it may write in your Booking HQ. Those checks are wired to the recommended assistant. They are not wired to the other two.

So the app refuses rather than pretending. Pick Gemini CLI and the terminal answers with one calm line saying this assistant cannot use Booked Solid safety checks yet, and nothing runs. The app will not quietly hand your inbox to an assistant it cannot supervise.

Local AI (Ollama) is the different one: it runs a model on your own machine, offline, and it still borrows the recommended assistant's safety checks, so that has to be installed first. There is a separate article on setting Ollama up.

The ChatGPT card on Connections is not the app's brain

This one costs people an evening, so it is worth reading twice. On Connections you will find a card named after ChatGPT and, further down the same list, a card called OpenAI (images). Neither of them changes what Otto runs on.

• The ChatGPT card is the Codex CLI, a coding assistant for the terminal. Otto does not run on it.
• OpenAI (images) is the one that makes flyers and social graphics. Both cards take the same kind of key, which is exactly why saving it on the wrong one looks completely successful.

If the real problem is cost, change this instead

Next to Assistant in that same Advanced panel is Thoroughness, with three settings: Most thorough, Balanced and Fastest. Booked Solid starts you on Balanced on purpose. Moving to Fastest gets more work out of the same plan on straightforward jobs, and it is the lever that actually changes what you spend. There is a separate article on what each setting changes.

Good to know

Whatever you pick applies to the next conversation you start, not the one already open.