Claude-skill-registry codex-cli

OpenAI Codex CLI fundamentals for code analysis, review, and validation. Use when (1) executing codex commands for code review/analysis, (2) configuring models (gpt-5.2-codex/gpt-5.2/gpt-5.1-codex-max/codex-mini), sandbox modes (read-only/workspace-write), or reasoning effort (low/medium/high/xhigh), (3) managing Codex sessions with resume, (4) integrating Codex into automation scripts. Do NOT use for orchestration patterns (use codex-claude-loop instead).

install

source · Clone the upstream repo

git clone https://github.com/majiayu000/claude-skill-registry

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/majiayu000/claude-skill-registry "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/data/codex-cli" ~/.claude/skills/majiayu000-claude-skill-registry-codex-cli-3be91d && rm -rf "$T"

manifest: skills/data/codex-cli/SKILL.md

Codex CLI Skill

⚠️ Environment Notice

Environment	Git Repo	Command Format
Interactive terminal	Any	`codex "prompt"`
Claude Code / CI	✅ Yes	`codex exec -s read-only "prompt"`
Claude Code / CI	❌ No	`codex exec --skip-git-repo-check -s read-only "prompt"`

Non-TTY environments (Claude Code, CI pipelines, scripts) require

codex exec

Git Repository Detection

Before executing Codex commands, check if the working directory is a Git repository:

# Check Git repository status
git rev-parse --git-dir 2>/dev/null && echo "Git repo: YES" || echo "Git repo: NO"

Git repo exists: Use standard commands
No Git repo: Add
```
--skip-git-repo-check
```
flag (requires user awareness of security implications)

Quick Start

In Git Repository (Standard)

# Basic code review (terminal)
codex "Review this code for bugs"

# Non-interactive mode (Claude Code/CI)
codex exec -s read-only "Review this code for bugs"

# With specific model and reasoning effort
codex exec -s read-only -m gpt-5.2-codex -c model_reasoning_effort=high "Deep analysis"

# With image input
codex exec -s read-only -i screenshot.png "What's shown here?"

Outside Git Repository

# IMPORTANT: --skip-git-repo-check required for non-Git directories
# Ask user permission before using this flag

codex exec --skip-git-repo-check -s read-only "Review this code for bugs"

# With options
codex exec --skip-git-repo-check -s read-only -m gpt-5.2-codex "Deep analysis"

Session Resume (Special Syntax)

# IMPORTANT: Options must come BEFORE 'resume' subcommand
# SESSION_ID is from previous command output (e.g., 019ae3a3-f1cf-7dc1-8eee-8f424ae7a6f0)

# In Git repository
codex exec -s read-only resume [SESSION_ID] "Continue the analysis"

# Outside Git repository
codex exec --skip-git-repo-check -s read-only resume [SESSION_ID] "Continue the analysis"

Reference Documentation

Commands Reference -
```
codex
```
,
```
resume
```
,
```
apply
```
, input/output patterns
Options Reference - Models, sandbox, reasoning effort, approval modes
Examples - Code review, security analysis, automation scripts

Available Models

Full model details: See Options Reference

Model	Best For
`gpt-5.2-codex`	Complex analysis, critical systems (recommended)
`gpt-5.2`	General AI tasks, multi-domain
`gpt-5.1-codex-max`	Security audits, architecture review
`gpt-5.1-codex-mini`	Quick checks, batch operations

Reasoning Effort

Usage examples: See Options Reference

Level	Use Case
`low`	Simple checks, syntax review
`medium`	Standard code review (default)
`high`	Security audits, complex logic
`xhigh`	Critical systems, exhaustive analysis

Sandbox Modes

Mode	Description
`read-only`	Cannot modify files (safest, recommended)
`workspace-write`	Can modify workspace files
`danger-full-access`	Full system access (use sparingly)

Key Options

Full options list: See Options Reference

Common Patterns

Full examples: See Examples for detailed patterns

Essential Patterns

# Code review (Claude Code/CI)
codex exec -s read-only "Review: $(cat src/auth.js)"

# Maximum depth analysis
codex exec -m gpt-5.2-codex -c model_reasoning_effort=xhigh -s read-only "Security audit"

# Session continuity
codex exec -s read-only resume [SESSION_ID] "Continue analysis"

# Cross-directory
codex exec -C ./backend --add-dir ./frontend -s read-only "Review API"

# Non-Git directory (ask user first)
codex exec --skip-git-repo-check -s read-only "Analyze code"

Platform-Specific Notes

Windows Limitations

Issue Description Workaround

-C

with absolute paths

cwd is not absolute

error with Windows paths like

C:\path

Use relative paths (

./subdir

) or run from target directory

Path separators

Backslashes may cause issues

Use forward slashes (

) in paths

# AVOID on Windows:
codex exec -C C:\Projects\myapp -s read-only "analyze"

# USE instead:
cd C:\Projects\myapp && codex exec -s read-only "analyze"
# OR use relative paths:
codex exec -C ./myapp -s read-only "analyze"

Error Handling

Error recovery patterns: See Examples

Error	Cause	Solution
`stdin is not a terminal`	Using `codex` in non-TTY	Use `codex exec`
`Not inside a trusted directory`	Not in Git repo	Ask user, then use `--skip-git-repo-check`
`invalid value for '--ask-for-approval'`	Invalid approval value	Use: `untrusted` , `on-failure` , `on-request` , `never`
`unexpected argument` after `resume`	Options after `resume`	Place options BEFORE `resume` subcommand
`cwd is not absolute`	Windows absolute path	Use relative paths or `cd` first
`No prompt provided via stdin`	Empty prompt	Ensure prompt string is not empty

Timeout Configuration

Task Type	Recommended Timeout	Claude Code Tool
Quick checks	2 minutes	`timeout: 120000`
Standard review	5 minutes	`timeout: 300000`
Deep analysis	10 minutes	`timeout: 600000`

Recommendation: Use

timeout: 600000

for all Codex exec commands (model_reasoning_effort=high/xhigh can take 3-7 minutes).

Best Practices

Use
codex exec
in Claude Code and CI environments (non-TTY)
Default to
-s read-only
for all review tasks
Match model + reasoning effort to task complexity
Use
resume
to maintain session context
Use
--add-dir
for cross-project context
Use
--full-auto
only in controlled environments
Ask user before
--skip-git-repo-check
- explain implications
Check valid approval values - only use
```
untrusted
```
/
```
on-failure
```
/
```
on-request
```
/
```
never
```
Set 10-minute timeout for all Codex exec commands (
```
timeout: 600000
```
)