# Codex Features and Practical Usage 🧩 Tired of re-explaining the same workflow to Codex every time? Agent Skills let you package a reusable playbook once, and Codex loads it only when it is actually needed. 🏷️ Title: Agent Skills (SKILL.md) 🔗 URL: 📘 Overview Agent Skills package routine workflows into a single `SKILL.md` file you can reuse. Only a skill's name and description sit in Codex's context at all times; the full body loads when Codex decides to invoke it. You scope skills by where you place them: repository-wide, personal, or machine-level. ⚙️ How It Works ・A skill is a folder with `SKILL.md` (required) plus optional `scripts/` (executable code), `references/` (docs), `assets/` (templates), and `agents/openai.yaml` (UI config). ・`SKILL.md` opens with frontmatter containing `name` and `description`. A good description states clearly when the skill triggers and what its boundaries are. ・Codex scans several locations in priority order: the repo's `.agents/skills`, `$REPO_ROOT/.agents/skills`, your personal `$HOME/.agents/skills`, the admin path `/etc/codex/skills`, and OpenAI's bundled built-in skills. ・Progressive disclosure keeps only names, descriptions, and paths in the initial context (capped around 8,000 characters). The full body loads on invocation, so many installed skills won't bloat the prompt. 🛠️ Practical Usage ・The easiest way to author one is the built-in `$skill-creator`. It walks you through what the skill does, when it triggers, and whether to bundle scripts (instruction-only is the default). ・Invoke explicitly with `/skills` in the CLI/IDE, or mention a skill by name like `$skill-name`. Codex also selects skills implicitly when your task matches the description. ・To forbid implicit selection for a skill, set `policy.allow_implicit_invocation` to `false` in `agents/openai.yaml`. ・To disable a skill without deleting it, add a `[[skills.config]]` entry with its `path` and `enabled = false` in `~/.codex/config.toml`. 💡 Use Cases Encode error-prone, brittle routines such as release procedures, how to run the E2E suite, or the correct way to use an internal library. Anyone on the team then gets consistent results from Codex. Put shared workflows under the repo and personal habits under `$HOME/.agents/skills` for a clean split. ⚠️ Caveats ・Duplicate skill names across locations are not merged; both appear in the selector, so keep names unique. ・A vague description breaks implicit matching. Front-load key use cases and be concrete. ・With many skills installed, descriptions may be shortened to save context. If changes don't show up, restart Codex. #OpenAICodex# #AgentSkills#

Codex rules for better clanking 1. Organise your projects in project folders - more threads - more granular - less clutter 2. Codex can self organise - create automations for decluttering - archive old threads 3. Pin Projects & Threads - rename threads - pin long term work

# Codex Features and Practical Usage 📝 Stop repeating the same context in every prompt. AGENTS.md is a layered instruction file that teaches Codex your build steps and code conventions for good. 🏷️ Title: Hierarchical Project Instructions (AGENTS.md) 🔗 URL: 📘 Overview AGENTS.md files are persistent instructions Codex reads before starting work. Encode your project norms, build commands, and code standards in Markdown, and Codex automatically discovers and applies them. The defining trait is a layered model where files closer to your current directory take precedence. ⚙️ How It Works Codex builds an instruction chain with strict precedence. ・Global (`~/.codex/`): checks `AGENTS.override.md` first, then `AGENTS.md` ・Project (Git root down to cwd): at each level checks `AGENTS.override.md`, then `AGENTS.md`, then custom fallback names ・Merge: files concatenate from the root downward with blank lines; later files (closer to cwd) override earlier ones It stops adding files once the combined size hits `project_doc_max_bytes` (32 KiB default). Naming conventions: ・`AGENTS.md`: the standard instruction file ・`AGENTS.override.md`: a temporary replacement that takes precedence at its level ・fallback names: configurable via `project_doc_fallback_filenames` (e.g. `TEAM_GUIDE.md`) 🛠️ Practical Usage Split by role for best effect. ・`~/.codex/AGENTS.md` (global): universal personal preferences, e.g. "Always run `npm test` after editing JS," "Prefer `pnpm`" ・repo-root `AGENTS.md`: team norms like linting standards, documentation expectations, and review criteria ・subdirectory `AGENTS.override.md` (e.g. `services/payments/`): override broader rules for a specific domain without deleting parent guidance Verify what loaded by asking Codex to summarize the current instructions, e.g. `codex --ask-for-approval never "Summarize the current instructions."` 💡 Use Cases In a monorepo where only the payments service needs a different test command or review bar, dropping a `services/payments/AGENTS.override.md` switches the rules on only when Codex works under that path. The "Review guidelines" you write here also apply to GitHub's `@/codex review`. ⚠️ Caveats Codex rebuilds the instruction chain on every run, so there is no cache to clear — if guidance looks stale, restart in the target directory. Empty files are skipped and non-existent fallback names are ignored. The `CODEX_HOME` environment variable overrides the default profile location. #OpenAICodex# #AGENTSmd#

codex tip: teach code review what your team keeps repeating. add a “Code Review Rules” section to AGENTS.md. codex will apply your repo-specific guidance and cite it on pull requests.

Codex Code Review can now use custom repository rules in AGENTS.md. Start with a check your reviewers keep repeating. Keep it concise and scoped so Codex can catch repository-specific issues even when the relevant context is siloed.