GPT‐5.4 in Deep

GPT-5.4 now powers Amp's deep mode.

It's the best model in the world right now.

It's faster than GPT-5.3-Codex and still as great at coding.

But, out of the box, GPT-5.4 was too chatty. That's not what we want for deep; it's not a pair programmer, it's supposed to go off and solve the problem.

So we tuned GPT-5.4 to behave like GPT-5.3-Codex.

Once we had that, we started to use it exclusively; even for interactive tasks. We run it at very high reasoning (deep^3) and still prefer it when we need fast interaction and fast reaction. It takes steering better than GPT-5.3-Codex.

To use it: open the command palette with Ctrl-O and run the command mode: use deep in the Amp CLI, or select deep mode in the Amp editor extension's prompt field. By default it uses deep^2, you can switch to deep^3 by hitting Opt-D.