IDE vs terminal vs OpenAI-native: the philosophy that drives the rest
The deepest difference here is not features or price — it is **where the agent lives**. That choice cascades into setup friction, daily workflow shape, tool access, and what kinds of tasks each tool is good at.
**Cursor lives in an IDE.** You open a folder, you see a file tree, you see open tabs, you see a diff. The agent operates inside that mental model — multi-file edits inside Composer, chat with codebase context, inline completion at the cursor. The IDE is doing a lot of the work: indexing your repo, tracking which files you've edited, surfacing language-server diagnostics. The agent is a feature inside a familiar shape.
**Claude Code lives in your terminal.** You `cd` into a repo, you run `claude`, and a CLI starts a conversation that can read files, write files, run shell commands, edit configs, drive your existing tooling (git, npm, docker, kubectl, gh, your test runner). The agent doesn't index your repo into a vector store — it greps, reads, and reasons over what it pulls. Everything is auditable in your scrollback. You can pipe it. You can run it over SSH. You can pin a session to a tmux pane and watch it work.
**Codex CLI lives in your terminal too**, but rooted in OpenAI's stack. Same shape as Claude Code at first glance — `cd` into a repo, run `codex`, get a tool-use agent that can read, write, exec. The differences show up in the model behind it (GPT-5 family rather than Claude), the approvals UX (Codex defaults to asking before destructive actions, with policies like 'auto-approve reads, ask before writes'), and the deeper tie-in to ChatGPT account billing.
**Consequences for daily work.** If most of your day is in an IDE writing application code, Cursor's shape is the lowest-friction win — the agent is one keybind away. If most of your day is in a terminal driving infra, CI, scripts, deploys, multi-repo workflows, or anything where the IDE is not the center, the CLI agents (Claude Code and Codex CLI) match your existing workflow without forcing you into a new editor. If you live in the OpenAI ecosystem (ChatGPT account, OpenAI API for everything else), Codex CLI is the lowest-context-switch CLI. If you want the deepest agent stack — hooks, skills, subagents, slash commands, MCP, custom tool definitions — Claude Code is currently the most opinionated and most capable CLI agent shipping in 2026.
Most senior engineers we know end up running two of these in parallel — Cursor for application code, Claude Code (or Codex CLI) for everything else. It is not an either/or for power users; it is a question of which is your primary.