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Deep-dive course

Codex Tutorial: OpenAI's Coding Agent in Depth

8 lessons, roughly 92minutes end to end. Start from what Codex actually does and build up to integrating it into your team's workflow -- with diagrams, comparison tables, and worked examples at every step, not just definitions.

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Course outline

  1. 1What Codex Actually DoesCodex is OpenAI's code-generation agent that takes a natural-language task and produces a diff you can review -- not autocomplete, but full planning and iteration.Beginner12 min
  2. 2CLI, IDE Extension, and Cloud SandboxCodex runs in three distinct modes -- command-line, integrated into your editor, and a remote sandbox -- each with different tradeoffs around security, latency, and integration depth.Beginner12 min
  3. 3Writing a Task Codex Can Act OnA good Codex task is specific, scoped to one logical change, includes examples if needed, and describes success criteria -- not a vague wish list.Beginner10 min
  4. 4Environment Setup and the Context Codex UsesCodex needs to see files, tests, and type definitions to reason well. Setting up the right context window is as important as writing the task clearly.Intermediate12 min
  5. 5Reviewing a Codex Diff Like a Pull RequestCodex produces a diff, but you review it exactly like a human-written PR -- checking logic, security, performance, and whether it actually solves the task.Intermediate12 min
  6. 6Using Tests as a Check on Codex's Own WorkTests are how you and Codex verify that a change is correct. Setting up the right tests makes Codex more reliable and catches mistakes faster.Intermediate10 min
  7. 7Codex Compared to Claude Code and OpenCodeThree major tools for AI-assisted coding serve different workflows. Understanding what each one is designed for helps you pick the right tool for your task.Intermediate12 min
  8. 8Scaling Codex from One Task to a Real WorkflowUsing Codex once is different from integrating it into a team workflow. This requires version control, task tracking, team agreements on review standards, and monitoring of success.Advanced12 min

What this course covers

Every lesson includes at least one worked example of a real Codex workflow, and several include original ToolDix diagrams showing the task-to-diff pipeline, the three deployment modes, task scoping patterns, the review checklist, and scaling from personal use to team workflows. Each lesson also cites the primary sources it draws from -- OpenAI's official Codex documentation, best practices from production engineering, and real-world case studies -- so you can go deeper on any single topic.