Module 03 · beginner · 45 min

Project Setup

A reliable Codex project combines clear instructions, a reproducible environment, an intentional sandbox policy, and commands that prove the work is correct.

Create a project baseline

Open the repository as a Codex project, run /init, and verify the generated instructions. Identify the default branch, package manager, environment files, and commands that start and validate the application.

/init
# then verify
npm install
npm test
npm run build

Local, worktree, or cloud

Local tasks operate in the saved checkout. Worktree tasks isolate Git state and are ideal for parallel changes. Cloud tasks run in a configured cloud environment when available.

Local: Use the saved checkout
Worktree: Isolated Git state
Cloud: Remote configured execution

Settings and profiles

Use Codex settings for defaults and project behavior. Keep machine-specific preferences outside the repository; commit only configuration the whole team should share.

# ~/.codex/config.toml
model = "gpt-5.6-terra"
model_reasoning_effort = "medium"

Definition of done

Write down which tests, linters, builds, browser checks, or manual inspections are proportionate to each change. A setup is complete only when another agent can reproduce it.

Continue learning

Use the official OpenAI Codex documentation as the final reference for current commands, settings, and availability.

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