Part 1: Understanding Codex
What Codex is
Codex is a tool-using agentic workspace: You give it a goal and it plans the work, uses available tools and context, and produces a result for you to review. It can read and write files on your computer, connect to external services through plugins and other integrations, run multi-step tasks without asking for guidance, generate code and scripts when a task needs them, and maintain context across a persistent workspace.
Specific capabilities that make Codex worth using:
- Works alongside you on multiple tasks in parallel
- Pulls context from the apps and files you connect
- Uses a supported browser and desktop workflows when a task needs on-screen action
- Checks its own work, revises, and keeps going
- Holds a persistent goal across a long-running session, instead of treating each message as a one-off request
- Turns repeatable tasks into recurring workflows
- Helps route shared requests from places like Slack, email, or forms
- Lets you start, steer, approve, and review work from your phone while Codex works in the cloud or on a machine, such as a Mac Mini, that you keep awake
These capabilities make Codex useful both for delegating well-specified tasks and as a shared workspace for human-agent collaboration. Deciding which mode fits which needs is the meta-skill of modern knowledge work.
A note on Goals
A Goal in Codex, initiated using the /goal command, is a persistent objective that shapes an entire session rather than living and dying with a single message. Instead of re-briefing the agent on every turn, you tell it what “done” looks like, how success gets checked, and which constraints to respect. Codex then keeps working toward that outcome across interruptions and session breaks. Goals let you delegate long-horizon work, collaborate without losing the thread, and compound progress over time instead of restarting from scratch.
A simple test for when to use /goal: If you’d type the same sentence into three prompts in a row—“cite every factual claim, match the house style, never send without my review”—make it a goal instead.
Goals versus skills. A skill is a reusable set of packaged instructions (sometimes with scripts) that teaches Codex how to handle a recurring kind of task well. A goal, on the other hand, is what you’re trying to accomplish in a given stretch of work. It guides one session until the objective is met, then it’s done.
Codex on mobile
Codex also runs from your phone through the ChatGPT mobile app, remotely controlling the machine where your work is happening. The mobile app suits the lightweight parts of a workflow: You can kick off a task, answer a question, approve an action, or review a draft from anywhere. Heavier review still deserves a real screen.
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