The model ceiling just rose. Your architecture didn't. OpenAI's GPT-5.4, Codex, and agent stack upgrades expose a brutal truth: teams with access to frontier models still fail at execution because they lack system design discipline. OpenAI Just Raised the Ceiling for Coding Agents. Most Teams Still Need Help Getting Off the Floor TL;DR: OpenAI's GPT-5.4 & Codex upgrades demand expert agent workflow design. Learn why system architecture, not models, is the new bottleneck. GPT-5.4, Codex plugins, Skills, and computer-use workflows just made one thing clear: the bottleneck is no longer access to models. It is architecture, workflow design, and operational discipline. OpenAI did not just ship better models. It shipped more of the agent stack. That is the real story here.…