This message from the Zed discord (from a zed staffer) puts it clearly, I think:

“….you can use Claude code in Zed but you can’t hijack the rate limits to do other ai stuff in zed.”

This was a response to my asking whether we can use the Claude Max subscription for the awesome inline assistant (Ctl+Enter in the editor buffer) without having to pay for yet another metered API.

The answer is no, the above was a response to a follow up.

An aside - everyone is abuzz about “Chat to Code” which is a great interface when you are leaning toward never or only occasionally looking at the generated code. But for writing prose? It’s safe to say most people definitely want to be looking at what’s written, and in this case “chat” is not the best interaction. Something like the inline assistant where you are immersed in the writing is far better.