Codex Levels — Concept Guide
About 5 minutes
Target audience: Readers who want to assess their Codex proficiency and decide what capability to learn next
Prerequisites: Read Codex entry points
Codex Levels are a staged way to think about how much work you can safely delegate to Codex.
Start with chat-based advice, then move through repository reading, test execution, GitHub pull requests, and parallel task execution.
Learning Path
Section titled “Learning Path”- Read How to Use Codex Levels to treat levels as a way to define delegation boundaries, not as a score or competition
- Compare deliverables and completion criteria in Codex Level 0 to 10: An 11-Stage Framework
- Open the detailed page for your current level, then practice the same level in Codex Level Up
11-Stage Overview
Section titled “11-Stage Overview”| Level | Title | Concept keywords |
|---|---|---|
| Level 0 | Chat Advisor | coding advice outside the repository |
| Level 1 | Repository Reader | code investigation and related files |
| Level 2 | Focused Editor | bounded edits and diff review |
| Level 3 | Verified Implementer | small features, tests, completion criteria |
| Level 4 | Context Engineer | AGENTS.md and shared rules |
| Level 5 | GitHub Collaborator | issues, branches, PRs, and reviews |
| Level 6 | Harness Builder | permissions, approvals, checks, and constraints |
| Level 7 | Tool Operator | MCP, browsers, and connectors |
| Level 8 | Parallel Orchestrator | threads, worktrees, and subagents |
| Level 9 | Workflow Operator | CI, scheduled runs, monitoring, and recovery |
| Level 10 | Agent Platform Architect | agent roles, evaluation, audit, and improvement |
Practice with Tutorials
Section titled “Practice with Tutorials”After learning the concepts, use Codex Level Up to apply them through a Next.js personal portfolio site in practical repository work.
For the detailed Level 6 implementation, use Codex Harness to work through AGENTS.md, config.toml, Rules, Skills, Hooks, and CI validation.