codex-cli-best-practice

from vibe coding to agentic engineering - practice makes codex perfect

= Agents · = Commands · = Skills

🧠 CONCEPTS

| Feature | Location | Description | |---------|----------|-------------| | Commands | interactive session / slash popup | Built-in slash commands for session control — examples include /plan, /fast, /fork, /review, /status, /mcp, /agent, /apps, /model, and /permissions | | Subagents | .codex/agents/<name>.toml | Custom agents registered under [agents.<name>] with dedicated TOML role configs, parallel subagent orchestration, and CSV batch processing · Global settings live under (, , ) · Built-in: , , | | | | Reusable instruction packages with required + metadata and progressive disclosure via , , , and optional · Invoke explicitly via or , or implicitly by description match · Built-in examples: , , · Distributed via | | | | Distributable bundles combining skills + app integrations + MCP servers — local/personal system · Built-in: · Browse via or Codex App | | | → | Plugin catalog system (v0.121.0+) — accepts GitHub shorthand, git URLs, and local directories · Manifest at · Browse installed marketplaces via tabs | | | | Cross-session memory pipeline (v0.119.0+) — enable via and configure under · TUI control via (use · generate · reset) · Per-thread toggle persists in state DB · Scope is per-user, not per-project | | | | End-to-end usage patterns — explain codebase, fix bugs, write tests, prototype from screenshot, iterate UI, delegate to cloud, code review, update docs | | | → | Model Context Protocol for external tools — STDIO + Streamable HTTP servers · OAuth support () · Also acts as MCP via (exposes + tools) · (v0.119.0+): resource reads, elicitations, file-parameter uploads · (v0.121.0+): per server · CLI management: | | | | TOML-based layered config system · · · · (, , , , model providers, granular approvals) · system for project configs · · for custom system prompts | | | | Starlark-based command execution policies via — , , decisions with exact-prefix matching · Test via · Rules work alongside granular controls and user-managed approvals | | | | Project-level context for Codex CLI — hierarchical discovery from cwd to repo root, capped at 32 KiB () · for personal overrides | | | | User-defined shell scripts that inject into the agentic loop — logging, security scanning, validation, and custom automation · Requires feature flag | | | → | Fast Mode (1.5x speed, 2x credits) on gpt-5.4 — toggle with · GPT-5.3-Codex-Spark for near-instant iteration (Pro subscribers) | | | | Review branches, uncommitted changes, or specific commits — configurable in config.toml · Custom review instructions | | | | Agentic Engineering · Context Engineering · Vibe Coding | | | | Official best practices · · |