Codex Exec

Codex Exec Skill

Execute OpenAI Codex CLI prompts in non-interactive mode and return structured results. Enables Claude + Codex hybrid workflows.

Options

<prompt>          Required. The prompt to send to Codex CLI
--json            Return structured JSON Lines output
--output <path>   Save final message to file
--model <name>    Model override (default: Codex CLI default model)
--timeout <ms>    Execution timeout (default: 120000, max: 600000)
--full-auto       Enable auto-approval mode (codex -a full-auto)
--working-dir     Working directory for Codex execution
--effort <level>  Set reasoning effort level (minimal, low, medium, high, xhigh)
                  Maps to Codex CLI's model_reasoning_effort config
                  Default: uses Codex CLI's configured default
                  Recommended: xhigh for research/analysis tasks

Workflow

1. Pre-checks
   - Verify `codex` binary is installed (which codex || npx codex --version)
   - Verify authentication (OPENAI_API_KEY or logged in)
2. Build command
   - Base: codex exec --ephemeral "<prompt>"
   - Apply options: --json, --model, --full-auto, -C <dir>
   - Set --working-dir if specified
3. Execute
   - Run via Bash tool with timeout (default 2min, max 10min)
   - Or use helper script: node .claude/skills/codex-exec/scripts/codex-wrapper.cjs
4. Parse output
   - Text mode: return raw stdout
   - JSON mode: parse JSON Lines, extract final assistant message
5. Report results
   - Format output with execution metadata

Safety Defaults

• --ephemeral: No session persistence (conversations not saved)
• Default mode: Normal approval (Codex prompts for confirmation)
• Override with --full-auto only when explicitly requested

Output Format

Success (Text Mode)

[Codex Exec] Completed

Model: (default)
Duration: 23.4s
Working Dir: /path/to/project

--- Output ---
{codex response text}

Success (JSON Mode)

[Codex Exec] Completed (JSON)

Model: (default)
Duration: 23.4s
Events: 12

--- Final Message ---
{extracted final assistant message}

Failure

[Codex Exec] Failed

Error: {error_message}
Exit Code: {code}
Suggested Fix: {suggestion}

Helper Script

For complex executions, use the wrapper script:

node .claude/skills/codex-exec/scripts/codex-wrapper.cjs --prompt "your prompt" [options]

The wrapper provides:

• Environment validation (binary + auth checks)
• Safe command construction
• JSON Lines parsing with event extraction
• Structured JSON output
• Timeout handling with graceful termination

Examples

# Simple text prompt
codex-exec "explain what this project does"

# JSON output with model override
codex-exec "list all TODO items" --json

# Save output to file
codex-exec "generate a README" --output ./README.md

# Full auto mode with custom timeout
codex-exec "fix the failing tests" --full-auto --timeout 300000

# Specify working directory
codex-exec "analyze the codebase" --working-dir /path/to/project

Integration

Works with the orchestrator pattern:

• Main conversation delegates Codex execution via this skill
• Results are returned to the main conversation for further processing
• Can be chained with other skills (e.g., dev-review after Codex generates code)

Availability Check

codex-exec requires the Codex CLI binary to be installed and authenticated. The skill is only usable when:

1. codex binary is found in PATH (which codex succeeds)
2. Authentication is valid (OPENAI_API_KEY set or codex logged in)

If either check fails, this skill cannot be used. Fall back to Claude agents for the task.

Note: This skill is invoked via /codex-exec command, delegated by the orchestrator, or suggested by routing skills when codex is available. The intent-detection system can trigger it for research (xhigh) and code generation (hybrid) workflows.

Agent Teams Integration

When used within Agent Teams (requires explicit invocation):

1. As delegated task: orchestrator explicitly delegates codex-exec for code generation
2. Hybrid workflow: Claude team member analyzes → orchestrator invokes codex-exec → Claude reviews
3. Iteration: Team messaging enables review-fix cycles between Claude and Codex outputs

Orchestrator delegates generation task
  → /codex-exec invoked explicitly
  → Output returned to orchestrator
  → Reviewer validates quality
  → Iterate if needed

Research Workflow

When the orchestrator or intent-detection detects a research/information gathering request (routing_rule in agent-triggers.yaml):

1. Check Codex availability: Verify codex binary and OPENAI_API_KEY
2. If available: Execute with xhigh reasoning effort for thorough research
3. If unavailable: Fall back to Claude's WebFetch/WebSearch

Research Command Pattern

/codex-exec "Research and analyze: {topic}. Provide structured findings with sources." --effort xhigh --full-auto --json

Effort Level Guide

Code Generation Workflow

When routing skills detect a code generation task and codex is available:

1. Check availability: Verify codex CLI via /tmp/.claude-env-status-*
2. If available + new file creation: Suggest hybrid workflow
3. Hybrid pattern:
   • codex-exec generates initial code (fast, broad generation)
   • Claude expert reviews for quality, patterns, best practices
   • Iterate if needed

Suitable Tasks

• New file scaffolding
• Boilerplate generation
• Test stub creation
• Documentation generation

Unsuitable Tasks

• Modifying existing code (Claude expert better at understanding context)
• Architecture decisions (requires reasoning, not generation)
• Bug fixes (requires deep code understanding)

Code Generation Command Pattern

/codex-exec "Generate {description} following {framework} best practices" --effort high --full-auto

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