Official References: Best Practices · Instructions · Sandboxing
Why a second beginner guide is useful
Beginners rarely fail because Codex is weak. They fail because they start with an oversized first task.
This guide gives a safe first-day loop focused on control and evidence.
45-minute first-day loop
0–10 min: set boundaries
- confirm
AGENTS.mdrules - confirm sandbox and approval mode
- define files that must not change
10–25 min: run one narrow task
Pick something that touches only a few files.
Good starter examples:
- fix a broken doc link
- tighten a README section
- rename one confusing label
25–35 min: verify and review
Run a small verification set and inspect the diff.
- lint or docs checks
- scope check on changed files
- revert accidental edits
35–45 min: leave handoff evidence
Record:
- what changed
- what passed
- what remains
- who owns next action
Beginner prompt template
Goal:
<one concrete outcome>
Context:
<relevant files and constraints>
Constraints:
<what must not change>
Done when:
<commands and expected pass criteria>Beginner anti-patterns
Starting with a large refactor
Big first tasks hide mistakes and destroy feedback quality.
Skipping sandbox check
Most early incidents come from boundary mistakes, not code complexity.
Declaring done without command output
"Looks good" is not evidence.
Quick checklist
- boundaries defined
- one narrow task completed
- verification commands executed
- diff scope reviewed
- handoff note recorded
If these are true, your Codex onboarding loop is healthy.