myclaude/skills/codex/SKILL.md

name, description

name	description
codex	Execute Codex CLI for code analysis, refactoring, and automated code changes. Use when you need to delegate complex code tasks to Codex AI with file references (@syntax) and structured output.

Codex CLI Integration

Overview

Execute Codex CLI commands and parse structured JSON responses. Supports file references via @ syntax, multiple models, and sandbox controls.

When to Use

• Complex code analysis requiring deep understanding
• Large-scale refactoring across multiple files
• Automated code generation with safety controls

Fallback Policy

Codex is the primary execution method for all code edits and tests. Direct execution is only permitted when:

1. Codex is unavailable (service down, network issues)
2. Codex fails twice consecutively on the same task

When falling back to direct execution:

• Log CODEX_FALLBACK with the reason
• Retry Codex on the next task (don't permanently switch)
• Document the fallback in the final summary

Usage

Mandatory: Run every automated invocation through the Bash tool in the foreground with HEREDOC syntax to avoid shell quoting issues, keeping the timeout parameter fixed at 7200000 milliseconds (do not change it or use any other entry point).

codex-wrapper - [working_dir] <<'EOF'
<task content here>
EOF

Why HEREDOC? Tasks often contain code blocks, nested quotes, shell metacharacters ($, `, \), and multiline text. HEREDOC (Here Document) syntax passes these safely without shell interpretation, eliminating quote-escaping nightmares.

Foreground only (no background/BashOutput): Never set background: true, never accept Claude's "Running in the background" mode, and avoid BashOutput streaming loops. Keep a single foreground Bash call per Codex task; if work might be long, split it into smaller foreground runs instead of offloading to background execution.

Simple tasks (backward compatibility): For simple single-line tasks without special characters, you can still use direct quoting:

codex-wrapper "simple task here" [working_dir]

Resume a session with HEREDOC:

codex-wrapper resume <session_id> - [working_dir] <<'EOF'
<task content>
EOF

Cross-platform notes:

• Bash/Zsh: Use <<'EOF' (single quotes prevent variable expansion)
• PowerShell 5.1+: Use @' and '@ (here-string syntax)

  codex-wrapper - @'
  task content
  '@
  

Environment Variables

• CODEX_TIMEOUT: Override timeout in milliseconds (default: 7200000 = 2 hours)
  • Example: export CODEX_TIMEOUT=3600000 for 1 hour

Timeout Control

• Built-in: Binary enforces 2-hour timeout by default
• Override: Set CODEX_TIMEOUT environment variable (in milliseconds, e.g., CODEX_TIMEOUT=3600000 for 1 hour)
• Behavior: On timeout, sends SIGTERM, then SIGKILL after 5s if process doesn't exit
• Exit code: Returns 124 on timeout (consistent with GNU timeout)
• Bash tool: Always set timeout: 7200000 parameter for double protection

Parameters

• task (required): Task description, supports @file references
• working_dir (optional): Working directory (default: current)

Return Format

Extracts agent_message from Codex JSON stream and appends session ID:

Agent response text here...

---
SESSION_ID: 019a7247-ac9d-71f3-89e2-a823dbd8fd14

Error format (stderr):

ERROR: Error message

Return only the final agent message and session ID—do not paste raw BashOutput logs or background-task chatter into the conversation.

Invocation Pattern

All automated executions must use HEREDOC syntax through the Bash tool in the foreground, with timeout fixed at 7200000 (non-negotiable):

Bash tool parameters:
- command: codex-wrapper - [working_dir] <<'EOF'
  <task content>
  EOF
- timeout: 7200000
- description: <brief description of the task>

Run every call in the foreground—never append & to background it—so logs and errors stay visible for timely interruption or diagnosis.

Important: Use HEREDOC (<<'EOF') for all but the simplest tasks. This prevents shell interpretation of quotes, variables, and special characters.

Examples

Basic code analysis:

# Recommended: with HEREDOC (handles any special characters)
codex-wrapper - <<'EOF'
explain @src/main.ts
EOF
# timeout: 7200000

# Alternative: simple direct quoting (if task is simple)
codex-wrapper "explain @src/main.ts"

Refactoring with multiline instructions:

codex-wrapper - <<'EOF'
refactor @src/utils for performance:
- Extract duplicate code into helpers
- Use memoization for expensive calculations
- Add inline comments for non-obvious logic
EOF
# timeout: 7200000

Multi-file analysis:

codex-wrapper - "/path/to/project" <<'EOF'
analyze @. and find security issues:
1. Check for SQL injection vulnerabilities
2. Identify XSS risks in templates
3. Review authentication/authorization logic
4. Flag hardcoded credentials or secrets
EOF
# timeout: 7200000

Resume previous session:

# First session
codex-wrapper - <<'EOF'
add comments to @utils.js explaining the caching logic
EOF
# Output includes: SESSION_ID: 019a7247-ac9d-71f3-89e2-a823dbd8fd14

# Continue the conversation with more context
codex-wrapper resume 019a7247-ac9d-71f3-89e2-a823dbd8fd14 - <<'EOF'
now add TypeScript type hints and handle edge cases where cache is null
EOF
# timeout: 7200000

Task with code snippets and special characters:

codex-wrapper - <<'EOF'
Fix the bug in @app.js where the regex /\d+/ doesn't match "123"
The current code is:
  const re = /\d+/;
  if (re.test(input)) { ... }
Add proper escaping and handle $variables correctly.
EOF

Parallel Execution

For multiple independent or dependent tasks, use --parallel mode with delimiter format:

codex-wrapper --parallel - <<'EOF'
---TASK---
id: analyze_1732876800
workdir: /home/user/project
---CONTENT---
analyze requirements @spec.md
---TASK---
id: implement_1732876801
workdir: /home/user/project
dependencies: analyze_1732876800
---CONTENT---
implement feature based on analyze_1732876800 analysis
---TASK---
id: docs_1732876802
workdir: /home/user/project/docs
---CONTENT---
independent task runs in parallel with analyze_1732876800
EOF

Delimiter Format:

• ---TASK---: Starts a new task block
• id: <task-id>: Required, unique task identifier
  • Best practice: use <feature>_<timestamp> format (e.g., auth_1732876800, api_test_1732876801)
  • Ensures uniqueness across runs and makes tasks traceable
• workdir: <path>: Optional, working directory (default: .)
  • Best practice: use absolute paths (e.g., /home/user/project/backend)
  • Avoids ambiguity and ensures consistent behavior across environments
• dependencies: <id1>, <id2>: Optional, comma-separated task IDs
• session_id: <uuid>: Optional, resume a previous session
• ---CONTENT---: Separates metadata from task content
• Task content: Any text, code, special characters (no escaping needed)

Resume Failed Tasks:

# Use session_id from previous output to resume
codex-wrapper --parallel - <<'EOF'
---TASK---
id: T2
session_id: 019xxx-previous-session-id
---CONTENT---
fix the previous error and retry
EOF

Output: Human-readable text format

=== Parallel Execution Summary ===
Total: 3 | Success: 2 | Failed: 1

--- Task: T1 ---
Status: SUCCESS
Session: 019xxx

Task output message...

--- Task: T2 ---
Status: FAILED (exit code 1)
Error: some error message

Features:

• Automatic topological sorting based on dependencies
• Unlimited concurrency for independent tasks
• Error isolation (failed tasks don't stop others)
• Dependency blocking (dependent tasks skip if parent fails)

Notes

• Binary distribution: Single Go binary, zero dependencies
• Installation: Download from GitHub Releases or use install.sh
• Cross-platform compatible: Linux (amd64/arm64), macOS (amd64/arm64)
• All automated runs must use the Bash tool with the fixed timeout to provide dual timeout protection and unified logging/exit semantics for automation (new sessions only)
• Uses --skip-git-repo-check to work in any directory
• Streams progress, returns only final agent message
• Every execution returns a session ID for resuming conversations
• Requires Codex CLI installed and authenticated