---
title: "The Codex Handbook: Build, Debug and Work with Files"
description: "Learn to use Codex for real projects: first builds, debugging, project instructions, skills and repeatable file workflows."
author: Power of AI
date: 2026-09-06
url: https://powerofai.ca/codex
---

# The Codex handbook: build, debug and work with your files

Learn to use Codex for real projects: first builds, debugging, project instructions, skills and repeatable file workflows.

Your idea can become a working thing.

Start with a useful project, learn how to give it context, and keep pushing through the parts that make it dependable. These guides connect the first prompt to the files, behavior and checks that make a result worth keeping.

## Start with your situation

### I have never coded. Where do I start?

Make a small local project and learn the review loop.

[Getting Started with Codex: Your First Project](/codex/getting-started)

### I have a project but the agent keeps missing context.

Give recurring expectations a durable home.

[AGENTS.md: Give Codex Useful Project Instructions](/codex/project-instructions)

### I keep doing the same task.

Extract the method, then test it on fresh inputs.

[Codex Skills and Repeatable Workflows](/codex/skills-and-repeatable-work)

## In the handbook

### Getting started with Codex: your first project, from folder to finished result

Start a useful Codex project with a clear brief, a bounded folder, a working result and a review you can perform even as a beginner.

[Getting Started with Codex: Your First Project](/codex/getting-started)

### Build your first AI-assisted tool: a CSV checker you can actually use

A complete beginner-friendly coding project: specify a CSV checker, build a local interface, handle messy inputs and verify downloadable results.

[Build Your First Tool with Codex: A CSV Checker](/codex/build-your-first-tool)

### Debug with Codex: turn “it is broken” into a verified repair

A practical Codex debugging workflow: reproduce a bug, trace the cause, make a focused fix and test the behavior that originally failed.

[Debugging and Testing with Codex](/codex/debugging-and-testing)

### AGENTS.md and project context: teach Codex how this project works

Write useful Codex project instructions, keep context focused and create handoffs that let a long project continue without starting over.

[AGENTS.md: Give Codex Useful Project Instructions](/codex/project-instructions)

### Codex skills and repeatable workflows: stop rebuilding the same request

Turn a successful Codex workflow into reusable instructions, templates and scheduled work, with concrete examples and checks for missing inputs.

[Codex Skills and Repeatable Workflows](/codex/skills-and-repeatable-work)

## Connect it to a bigger project

- [How AI File Access Works: Uploads and Local Folders](/workflows/ai-file-access)
- [Test a Website with an AI Browser Agent](/computer-use/browser-testing)
- [Turn Research into a Searchable Website with AI](/workflows/research-to-website)

[Read the main AI guide](/guide/how-to-use-ai) | [Try the working showcase](/showcase).