How to use Codex during a working day, with six practical prompts

You open a project, find a half-finished task and spend the first part of the morning remembering what changed. Later, a test fails. By the afternoon, someone needs a clear update. Codex can help at each point, provided the work has a clear purpose and something you can check.

Codex is OpenAI’s coding agent. With the appropriate tools and permissions, it can inspect project files, change code and run commands. The Codex CLI overview describes these capabilities. Access depends on your setup; a prompt cannot give it a missing connection or permission.

Here is a practical way to use it across a working day, with one project example and six prompts you can adapt. The aim is to finish a useful, reviewable piece of work and understand what happened along the way.

Set up the project context once

Open the correct project folder or repository, the collection of files and version history for the project. Point Codex to the current requirements, relevant design and instructions for running the application. Check whether someone already has work in progress before starting your change.

An optional AGENTS.md file can hold shared instructions such as the project layout, test commands and coding conventions. Keep it short and accurate. Today’s task belongs in the task brief; stable team guidance belongs in the shared instructions. OpenAI’s workflow guide distinguishes this recognised file from other optional planning conventions.

Use your organisation’s approved account and access settings. Give the task only the information it needs, using sanitised examples where appropriate. Keep passwords and production customer data out of prompts. Written instructions guide behaviour; configured permission boundaries control what local commands can access.

Follow one change through the day

Example: an internal task dashboard needs an “Overdue only” filter. For this exercise, the team agrees that overdue means an unfinished task with a due date earlier than today in Europe/London. Tasks due today, completed tasks and tasks without a due date are excluded. Existing search must still work.

These are example product rules, not universal definitions. Agree your own before building. The times below describe a sequence you can fit around your day, rather than a timetable or a promise about how long the work takes.

Use the same approach beyond coding

If you work in product or delivery, use Codex to compare agreed requirements with project documentation, prepare a test checklist or draft a stakeholder explanation from verified results. Supply the relevant files and define the output. Connections to a board or messaging tool need to be available and authorised; they are not implied by asking for a draft.

Keep decisions with the right people. Codex can highlight ambiguity in “overdue”, but the team still needs to decide what that means for its users. If you are learning to code, ask it to explain one changed function and then trace an example through it yourself.

Try it on one small task

Choose a reversible change you understand well enough to assess. Replace the dashboard rules in these prompts with your own project brief, keep the context current and reserve time to review the result.

• Before: name the outcome, relevant sources, permitted changes and evidence needed.
• During: resolve important uncertainty, inspect progress and record real check results.
• After: review the change and leave an accurate status with the next step.

At the end of the day, compare the whole experience: time spent explaining, building, correcting and reviewing. Use that evidence to decide where Codex helped and what to improve tomorrow.