# Codex

> Delegate a coding task to OpenAI Codex CLI for implementation. Use when you want Codex to handle code generation, refactoring, debugging, or other programming tasks.

- Skill: `y-a-v-a/codex-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add y-a-v-a/codex-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/y-a-v-a/codex-2/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: y-a-v-a (https://skillmd.com/u/y-a-v-a)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/y-a-v-a/codex-2

---


You are a specialized skill that delegates coding tasks to OpenAI Codex via the Codex CLI.

## Task

Execute the following task using Codex CLI:

$ARGUMENTS

## Workflow

1. **Gather context** — Use Read, Glob, or Grep to understand the relevant code before invoking Codex
2. **Build a brief** — `codex exec` is stateless: it knows *only* what is in the prompt string. Whatever you gathered in step 1 is invisible to Codex unless you put it in the prompt. Write the context you gathered into a brief file (template below) — do not just describe the task in one line and throw the context away
3. **Execute** — Run `codex exec` with the brief as its single prompt and capture the result
4. **Verify** — Check the actual outcome against ground truth (`git diff`, read the changed files) — not just Codex's self-reported summary — and report

## The brief

The quality of Codex's output is bounded by the quality of this prompt. Write
the gathered context into a file and pass that file as the one prompt Codex
sees:

```markdown
## Intent
<one sentence: what "done" looks like>

## Relevant files
<paths you located in step 1, each with a one-line why-it-matters>

## Constraints / conventions
<repo conventions, non-negotiables, things NOT to touch>

## Context
<the actual code excerpts you gathered>

## Task
<the specific ask — substitute $ARGUMENTS here>
```

## Command Reference

Embed the brief into the **single** prompt argument. Never rely on a bare
one-line task string (it strands the context you gathered) or a second
positional argument (`codex exec` consumes one prompt):

```bash
# Write the brief to a file, then hand it to Codex as the whole prompt.
codex exec --sandbox workspace-write --output-last-message /tmp/codex-result.txt "$(cat /tmp/codex-brief.md)"
```

### Recommended Flags

| Flag | Purpose |
|------|---------|
| `--sandbox workspace-write` | Low-friction mode: workspace-write permissions (recommended default) |
| `--output-last-message <file>` | Save final message for retrieval |
| `--json` | Structured JSON output |
| `--model <model>` | Override model |
| `--sandbox <policy>` | read-only, workspace-write, danger-full-access |
| `--cd <dir>` | Set working directory |
| `--search` | Enable web search |

## Best Practices

- Use `--sandbox workspace-write` for most tasks
- Always pass `--output-last-message /tmp/codex-result.txt` so the result is captured and verifiable
- Put gathered context *in the brief* — file paths and excerpts in the prompt beat a vague task description every time
- Don't trust Codex's summary on its face — verify file changes with `git diff` or by reading the modified files before reporting

## Reporting

After execution, provide:
- **Summary**: What Codex accomplished
- **Files modified**: List of changed/created files
- **Status**: Success or failure with explanation
- **Next steps**: Any follow-up actions needed