OpenAI Codex CLI Skill

This skill provides integration with OpenAI's Codex CLI for code review and task execution.

Quick Reference

Code Review

Review uncommitted changes:

codex review --uncommitted

Review against a branch:

codex review --base main

Review a specific commit:

codex review --commit <sha>

Review with custom instructions:

codex review "Focus on security vulnerabilities"

Task Execution

Run a task non-interactively:

codex exec "<prompt>"

With full auto mode (sandboxed automatic execution):

codex exec --full-auto "<prompt>"

With specific model:

codex exec -m o3 "<prompt>"

Available Commands

Command	Description
codex review	Run code review non-interactively
codex exec	Run tasks non-interactively
codex	Interactive mode
codex apply	Apply latest diff from Codex agent
codex resume	Resume previous session

Review Command Options

Option	Description
--uncommitted	Review staged, unstaged, and untracked changes
--base <branch>	Review changes against base branch
--commit <sha>	Review changes from a specific commit
--title <title>	Optional commit title for review summary
-c model=<model>	Use specific model

Exec Command Options

Option	Description
-m, --model <model>	Model to use (e.g., o3, gpt-4)
-s, --sandbox <mode>	Sandbox: read-only, workspace-write, danger-full-access
--full-auto	Low-friction sandboxed automatic execution
-C, --cd <dir>	Working directory
-i, --image <file>	Attach image(s) to prompt
-o, --output-last-message <file>	Write final response to file
--json	Output events as JSONL

Common Use Cases

1. Quick Code Review

Review current changes before committing:

codex review --uncommitted

2. PR Review

Review all changes in a feature branch:

codex review --base main --title "Feature: Add user authentication"

3. Focused Review

Review with specific focus:

codex review --uncommitted "Focus on:
1. Security vulnerabilities
2. Error handling
3. Performance issues"

4. Automated Task

Run a coding task:

codex exec "Add input validation to all API endpoints in src/api/"

5. Code Explanation

Get explanation of complex code:

codex exec "Explain the algorithm in src/utils/ranking.R"

6. Bug Investigation

Investigate test failures:

codex exec "Investigate why tests in tests/unit/ are failing"

Sandbox Modes

Mode	Permissions
read-only	Can read files, no writes
workspace-write	Can write to workspace (default with --full-auto)
danger-full-access	Full system access (use with caution)

Integration with Claude Code

When using this skill:

1. For code review: Use /codex-review command or run codex review directly
2. For tasks: Use /codex command or run codex exec directly
3. For complex workflows: Combine Codex output with Claude Code analysis

Example Workflow

1. Use Codex for initial review:

   codex review --uncommitted > review.txt
   

2. Have Claude Code analyze and summarize:

   • Read the review output
   • Identify critical issues
   • Suggest fixes

Best Practices

1. Use --full-auto for routine tasks - Speeds up execution with safe defaults
2. Specify --base for PR reviews - Ensures complete diff is reviewed
3. Add context to review prompts - Better reviews with specific focus areas
4. Check sandbox mode - Use appropriate permissions for the task
5. Save output for complex reviews - Use -o flag for later analysis