Course · 60 minutes · Codex
Zero to hero in 60 minutes
Learn what a model, a tool, a harness, an agent and a skill are, one layer at a time. Then install Codex on Windows and use it on real work tasks.
Fictional files for the labs. No real people, companies or figures.
The whole stack you will build, one layer per lesson.
Syllabus
Start here
How the course works, how to pick a reading level, and what to download before you begin.
The model
A model is a program that predicts text. It has no memory and cannot act, and it can be wrong with confidence.
Context
A model knows only its training and the text in front of it. That text is the context.
Tools
A model cannot act by itself. A tool is an action it asks for, and the software around it carries out.
Harness and agent
The harness is the software around a model. An agent is a model, a harness and tools working in a loop.
Install Codex on Windows
Install the ChatGPT desktop app, sign in with a work account, open a project folder and run a first task.
Briefing an agent
A six-part brief that tells an agent the goal, the inputs, the output, the limits and how to check the work.
Instructions and skills
Standing instructions in AGENTS.md, reusable skills, and plugins that connect an agent to other systems.
Practice labs
Pick the lab for your role and complete it with the starter pack. Each lab takes about fifteen minutes.
Checking and safety
How to check an agent's work, which data to keep out, and how permissions limit what it can do.
Labs
Lab for business analysts
Turn a process narrative into a BPMN diagram, then classify thirty-five data fields against a policy.
Lab for asset managers
Compare renewable generation with the P50 budget, then extract key dates from three PPA term sheets.
Lab for procurement
Score three supplier quotes against weighted criteria, then match twelve invoices to purchase orders.
Extra labs
Codex documentation (opens in a new tab)
OtterBlock is not affiliated with OpenAI. Codex and ChatGPT are OpenAI products.