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).

codeagent-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:

codeagent-wrapper "simple task here" [working_dir]

Resume a session with HEREDOC:

codeagent-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)

  codeagent-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: codeagent-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)
codeagent-wrapper - <<'EOF'
explain @src/main.ts
EOF
# timeout: 7200000

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

Refactoring with multiline instructions:

codeagent-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:

codeagent-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
codeagent-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
codeagent-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:

codeagent-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

Important:

• --parallel only reads task definitions from stdin.
• It does not accept extra command-line arguments (no inline workdir, task, or other params).
• Put all task metadata and content in stdin; nothing belongs after --parallel on the command line.

Correct vs Incorrect Usage

Correct:

# Option 1: file redirection
codeagent-wrapper --parallel < tasks.txt

# Option 2: heredoc (recommended for multiple tasks)
codeagent-wrapper --parallel <<'EOF'
---TASK---
id: task1
workdir: /path/to/dir
---CONTENT---
task content
EOF

# Option 3: pipe
echo "---TASK---..." | codeagent-wrapper --parallel

Incorrect (will trigger shell parsing errors):

# Bad: no extra args allowed after --parallel
codeagent-wrapper --parallel - /path/to/dir <<'EOF'
...
EOF

# Bad: --parallel does not take a task argument
codeagent-wrapper --parallel "task description"

# Bad: workdir must live inside the task config
codeagent-wrapper --parallel /path/to/dir < tasks.txt

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

Typical Workflow (analyze → implement → test, chained in a single parallel call):

codeagent-wrapper --parallel <<'EOF'
---TASK---
id: analyze_1732876800
workdir: /home/user/project
---CONTENT---
analyze @spec.md and summarize API and UI requirements
---TASK---
id: implement_1732876801
workdir: /home/user/project
dependencies: analyze_1732876800
---CONTENT---
implement features from analyze_1732876800 summary in backend @services and frontend @ui
---TASK---
id: test_1732876802
workdir: /home/user/project
dependencies: implement_1732876801
---CONTENT---
add and run regression tests covering the new endpoints and UI flows
EOF

A single codeagent-wrapper --parallel call schedules all three stages concurrently, using dependencies to enforce sequential ordering without multiple invocations.

codeagent-wrapper --parallel <<'EOF'
---TASK---
id: backend_1732876800
workdir: /home/user/project/backend
---CONTENT---
implement /api/orders endpoints with validation and pagination
---TASK---
id: frontend_1732876801
workdir: /home/user/project/frontend
---CONTENT---
build Orders page consuming /api/orders with loading/error states
---TASK---
id: tests_1732876802
workdir: /home/user/project/tests
dependencies: backend_1732876800, frontend_1732876801
---CONTENT---
run API contract tests and UI smoke tests (waits for backend+frontend)
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
  • Must be specified inside each task block; do not pass workdir as a CLI argument to --parallel
  • Each task can set its own workdir when different directories are needed
• 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)

Dependencies Best Practices

• Avoid multiple invocations: Place "analyze then implement" in a single codeagent-wrapper --parallel call, chaining them via dependencies, rather than running analysis first and then launching implementation separately.
• Naming convention: Use <action>_<timestamp> format (e.g., analyze_1732876800, implement_1732876801), where action names map to features/stages and timestamps ensure uniqueness and sortability.
• Dependency chain design: Keep chains short; only add dependencies for tasks that truly require ordering, let others run in parallel, avoiding over-serialization that reduces throughput.

Resume Failed Tasks:

# Use session_id from previous output to resume
codeagent-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