GPT 5.4 just dropped. I’ve been living in Opus 4.6 for months — it’s been my go-to for everything. So when OpenAI shipped 5.4, I wanted to see if it could earn a spot in the rotation.
The test: build a fully functional terminal emulator in Rust. Not a toy — tabs, split panes, a theme engine, preferences, a command palette. Start from an empty directory and see how far it gets.
The first compile shocked me. What came after shocked me more — for different reasons.
I kept pushing it through multiple rounds of iteration until it hit a wall. Where that wall is — and what it tells you about where agentic coding actually stands right now — is the whole point of this video.
