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
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WSL (Ubuntu) with tmux installed
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OpenAI Codex CLI installed and authenticated in WSL
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Claude Code running inside a tmux session
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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:
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Left pane: Claude Code (current)
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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":
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Inform user they need to start Claude Code inside tmux
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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
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ALWAYS use tmux interactive mode by default
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Let user see both AIs working side-by-side
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Wait adequate time (30-60s) for complex Codex queries
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Present both perspectives without bias
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Acknowledge both AIs can be wrong - user makes final decision