How do I install the With Codex skill?

Run npx skillmds@latest add enokisan/with-codex in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is With Codex safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: executes scripts. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with With Codex?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is With Codex free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published With Codex?

Enokisan (@enokisan) published this skill. Their other Agent Skills are listed on their SkillMD profile.

With Codex by enokisan — Agent Skill

Name: With Codex
Rating: 4.2 (5 reviews)
Author: Enokisan

With Codex

Enables Claude Code to collaborate with OpenAI Codex CLI on Windows. Use this skill when the user wants to get a second opinion from Codex, compare approaches between Claude and Codex, or leverage both AI assistants for collaborative problem-solving. This skill supports both non-interactive mode (automatic response retrieval) and interactive mode (visual pane splitting with tmux).

Enokisan Updated Sep 22, 2026

File contents

With Codex - Claude and Codex Collaboration

This skill enables collaboration between Claude Code and OpenAI Codex CLI for second opinions, validation, and collaborative problem-solving.

CRITICAL REQUIREMENT

Claude Code MUST be running inside a tmux session for this skill to work.

If not in tmux, inform the user: "このスキルを使用するには、tmuxセッション内でClaude Codeを起動する必要があります。以下のコマンドを実行してください:

tmux new-session -s claude
claude

Environment Requirements

WSL (Ubuntu) with tmux installed
OpenAI Codex CLI installed and authenticated in WSL
Claude Code running inside a tmux session
Skill scripts at: ~/.claude/skills/with-codex/scripts/

Standard Workflow (MUST FOLLOW)

When this skill is triggered, ALWAYS execute these steps in order:

Step 1: Setup - Split pane and start Codex

~/.claude/skills/with-codex/scripts/codex-manager.sh setup

This splits the current tmux pane:

Left pane: Claude Code (current)
Right pane: Codex CLI (newly created, with dark background)

Step 2: Claude performs its own analysis first

Analyze the user's request independently before querying Codex.

Step 3: Send the same prompt to Codex

~/.claude/skills/with-codex/scripts/codex-manager.sh send "YOUR_PROMPT_HERE"

Replace YOUR_PROMPT_HERE with the actual question/task from the user.

Step 4: Wait for Codex response

~/.claude/skills/with-codex/scripts/codex-manager.sh wait 60

Wait up to 60 seconds for Codex to complete its response.

Step 5: Capture Codex output

~/.claude/skills/with-codex/scripts/codex-manager.sh capture 200

Capture the last 200 lines of Codex's output.

Step 6: Present combined results

Present results in this format:

## Claude's Analysis
[Your independent analysis]

## Codex's Analysis
[Captured response from Codex]

## Synthesis
- **Agreement**: [Points where both AIs agree]
- **Differences**: [Alternative perspectives from Codex]
- **Recommendation**: [Best combined approach]

Step 7: Cleanup (when conversation ends or user requests)

~/.claude/skills/with-codex/scripts/codex-manager.sh cleanup

Available Commands

Command	Description
`setup`	Split pane and start Codex on the right
`send "prompt"`	Send prompt to Codex pane
`capture [lines]`	Capture Codex output (default: 100 lines)
`wait [timeout]`	Wait for response to stabilize (default: 60s)
`cleanup`	Close the Codex pane
`status`	Check pane status
`focus`	Switch focus to Codex pane

Error Handling

If setup fails with "Not running inside tmux":

Inform user they need to start Claude Code inside tmux
Provide the commands: tmux new-session -s claude then claude

Alternative: Non-Interactive Mode

Only use when tmux is unavailable or user explicitly requests:

codex exec "your prompt" 2>/dev/null

Best Practices

ALWAYS use tmux interactive mode by default
Let user see both AIs working side-by-side
Wait adequate time (30-60s) for complex Codex queries
Present both perspectives without bias
Acknowledge both AIs can be wrong - user makes final decision

---name: with-codexdescription: Enables Claude Code to collaborate with OpenAI Codex CLI on Windows. Use this skill when the user wants to get a second opinion from Codex, compare approaches between Claude and Codex, or leverage both AI assistants for collaborative problem-solving. This skill supports both non-interactive mode (automatic response retrieval) and interactive mode (visual pane splitting with tmux).---# With Codex - Claude and Codex CollaborationThis skill enables collaboration between Claude Code and OpenAI Codex CLI for second opinions, validation, and collaborative problem-solving.## CRITICAL REQUIREMENT**Claude Code MUST be running inside a tmux session for this skill to work.**If not in tmux, inform the user:"このスキルを使用するには、tmuxセッション内でClaude Codeを起動する必要があります。以下のコマンドを実行してください:```tmux new-session -s claudeclaude```"## Environment Requirements- WSL (Ubuntu) with tmux installed- OpenAI Codex CLI installed and authenticated in WSL- Claude Code running inside a tmux session- Skill scripts at: `~/.claude/skills/with-codex/scripts/`## Standard Workflow (MUST FOLLOW)When this skill is triggered, ALWAYS execute these steps in order:### Step 1: Setup - Split pane and start Codex```bash~/.claude/skills/with-codex/scripts/codex-manager.sh setup```This splits the current tmux pane:- Left pane: Claude Code (current)- Right pane: Codex CLI (newly created, with dark background)### Step 2: Claude performs its own analysis firstAnalyze the user's request independently before querying Codex.### Step 3: Send the same prompt to Codex```bash~/.claude/skills/with-codex/scripts/codex-manager.sh send "YOUR_PROMPT_HERE"```Replace `YOUR_PROMPT_HERE` with the actual question/task from the user.### Step 4: Wait for Codex response```bash~/.claude/skills/with-codex/scripts/codex-manager.sh wait 60```Wait up to 60 seconds for Codex to complete its response.### Step 5: Capture Codex output```bash~/.claude/skills/with-codex/scripts/codex-manager.sh capture 200```Capture the last 200 lines of Codex's output.### Step 6: Present combined resultsPresent results in this format:```markdown## Claude's Analysis[Your independent analysis]## Codex's Analysis[Captured response from Codex]## Synthesis- **Agreement**: [Points where both AIs agree]- **Differences**: [Alternative perspectives from Codex]- **Recommendation**: [Best combined approach]```### Step 7: Cleanup (when conversation ends or user requests)```bash~/.claude/skills/with-codex/scripts/codex-manager.sh cleanup```## Available Commands| Command | Description || ------- | ----------- || `setup` | Split pane and start Codex on the right || `send "prompt"` | Send prompt to Codex pane || `capture [lines]` | Capture Codex output (default: 100 lines) || `wait [timeout]` | Wait for response to stabilize (default: 60s) || `cleanup` | Close the Codex pane || `status` | Check pane status || `focus` | Switch focus to Codex pane |## Error HandlingIf setup fails with "Not running inside tmux":- Inform user they need to start Claude Code inside tmux- Provide the commands: `tmux new-session -s claude` then `claude`## Alternative: Non-Interactive ModeOnly use when tmux is unavailable or user explicitly requests:```bashcodex exec "your prompt" 2>/dev/null```## Best Practices1. ALWAYS use tmux interactive mode by default2. Let user see both AIs working side-by-side3. Wait adequate time (30-60s) for complex Codex queries4. Present both perspectives without bias5. Acknowledge both AIs can be wrong - user makes final decision

Frequently asked questions