Codex CLI Real-World Coding Workflow: The Setup Senior Devs Use in 2026

TL;DR The Codex CLI users who ship the most are not the ones with the cleverest prompts. They are the ones who wrote AGENTS.md once, wired up two MCP servers, and let /plan do the thinking on anything ambiguous. Default workflow: plan-first for unclear tasks, just-do-it for clear ones, three to four worktrees in parallel, GPT-5.5 for thinking work and GPT-5.4 Mini for everything boring. This guide is the loop, the trade-offs, and the seven mistakes that eat your first week. "The leverage in Codex CLI is not the model.