CODEX COURSE / 12 CORE + 06 PLATFORM
Build a dependable Codex operating system.
Move in order: establish the terminal and trust boundary, encode repository knowledge, extend the tool surface, then automate only workflows that already have evidence.
Enter the terminal safely
Install, authenticate, launch in the correct repository, and choose authority before asking Codex to act.
- 01Install Codex and prove the toolchainA working Codex CLI installation with a recorded version and a repeatable diagnostic path.
- 02Choose authentication without leaking credentialsAn authenticated CLI whose account, billing boundary, and local credential storage are understood.
- 03Run the first repository session like an engineerA scoped first task completed in the intended repository with visible verification.
- 04Set authority before autonomyA permission profile matched to task impact, with no accidental full-access default.
Make the work legible and repeatable
Control a live session, encode durable guidance, configure by scope, and turn changes into reviewable evidence.
- 05Control a long-running CLI sessionA session that remains legible and steerable across planning, implementation, and review.
- 06Make repository knowledge durable with AGENTS.mdA concise, verified AGENTS.md chain that teaches Codex how this repository is built and checked.
- 07Configure Codex by scope, not by accidentPredictable personal and repository behavior with explicit one-off overrides and no stale profile format.
- 08Turn changes into reviewable evidenceA repeatable change-test-diff-review loop with prioritized findings and an explicit acceptance decision.
Extend, govern, and automate
Connect MCP, package skills, add guardrails, then scale independent work into subagents and safe CI.
- 09Connect external systems through MCPA verified MCP connection with a narrow tool surface and explicit startup and approval policy.
- 10Package repeatable work as skillsA narrow, testable skill with a clear trigger and a justified distribution path.
- 11Add guardrails with hooks and rulesA reviewed hook and a tested command rule that improve control without pretending to be a complete security boundary.
- 12Scale from subagents to safe automationA bounded parallel workflow and a least-privilege automation path with machine-readable evidence.
Build directly on the OpenAI Platform
Keep these API architecture notes as the companion track for products that own Responses, tools, schemas, agent loops, realtime sessions, and model routing.
- 13Make Responses the system boundaryA request layer that can change models without changing your product contract.
- 14Give every tool a narrow contractA tool layer whose side effects can be reviewed, retried, and revoked.
- 15Treat schema as user experienceTyped model output that enters product code through a deliberate validation gate.
- 16Choose who owns the agent loopA bounded multi-step workflow with a named controller and stop conditions.
- 17Design Realtime as a live systemA realtime architecture tested against actual networks, voices, and interruption patterns.
- 18Keep model choice at the edgeA deployment that can adopt a new model through evidence and configuration rather than a rewrite.