Pragmatic Engineer: DHH's Agent-First Coding Workflow — 'Wearing a Mech Suit' with Multiple AI Agents in tmux

The Pragmatic Engineer·high signal

Gergely Orosz profiles DHH's shift to an agent-first workflow: he runs two AI models in tmux alongside neovim, describing it as 'wearing a mech suit' rather than being a project manager of agents. The shift happened when agents moved from tab-completion to agentic harnesses with Opus 4.5-class models producing merge-ready code. DHH argues Rails is one of the most token-efficient frameworks for agent workflows because testing is built into the framework, allowing agents to self-validate.