codex

Original：🇺🇸 English
Translated

Hand off a task to Codex CLI for autonomous execution. Use when a task would benefit from a capable subagent to implement, fix, investigate, or review code. Codex has full codebase access and can make changes.

2installs
Source0xbigboss/claude-code
Added on

NPX Install

npx skill4agent add 0xbigboss/claude-code codex

Tags

Translated version includes tags in frontmatter
codex-cliai-agentcode-automationcode-reviewdev-tool

SKILL.md Content

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Codex Subagent

Session ID: ${CLAUDE_SESSION_ID} Output: 
~/.claude/codex/${CLAUDE_SESSION_ID}/

Arguments

Task: $ARGUMENTS
Optional flags (only if user explicitly requests):
  • --model <model>
    : 
    gpt-5.2-codex
    (default), 
    gpt-5.2
    , 
    gpt-5-mini
    , 
    o3
  • --sandbox <mode>
    : 
    read-only
    , 
    workspace-write
    , 
    danger-full-access
Omit flags to use user's config defaults.

Context Depth

Minimal: Specific file/function → git state only Medium: Feature/multi-file → add recent changes Full: Investigation/unclear → add session summary

Gather Context

Always:
bash
pwd && git rev-parse --show-toplevel 2>/dev/null || echo "Not a git repo"
git branch --show-current 2>/dev/null && git status --short 2>/dev/null | head -20
Medium/Full:
bash
git diff --stat 2>/dev/null | tail -20
git log --oneline -5 --since="4 hours ago" 2>/dev/null
Full only: Session summary (work done, decisions, blockers)

Prompt Structure

Use CTCO format (Context → Task → Constraints → Output):
<context>
Working directory: {cwd}
Repository: {repo_name}
Branch: {branch}
{git_status}
{recent_changes if medium/full}
{session_summary if full}
</context>

<task>
{task from arguments}
</task>

<constraints>
- Implement EXACTLY what is requested
- Read files before changing
- Run tests/linters to validate
- State interpretation if ambiguous
</constraints>

<output>
Summary (≤5 bullets):
- **What changed**: Files and changes
- **Where**: file:line references
- **Validation**: Tests/linters run
- **Risks**: Edge cases to watch
- **Next steps**: Follow-up or "None"
</output>

Execute

Setup:
bash
mkdir -p ~/.claude/codex/${CLAUDE_SESSION_ID}
git rev-parse --show-toplevel 2>/dev/null && IN_GIT=true || IN_GIT=false
Run:
bash
codex exec --json \
  -o ~/.claude/codex/${CLAUDE_SESSION_ID}/summary-{timestamp}.txt \
  {--skip-git-repo-check if not in git} \
  {--full-auto OR --sandbox <mode>} \
  {-m <model> if requested} \
  - <<'CODEX_PROMPT'
{prompt}
CODEX_PROMPT > ~/.claude/codex/${CLAUDE_SESSION_ID}/progress-{timestamp}.jsonl
Flags:
  • Not in git: add 
    --skip-git-repo-check
  • Default: 
    --full-auto
    (workspace-write + auto-approval)
  • User-requested: 
    --sandbox <mode>
    or 
    -m <model>

Background vs Foreground

Background tasks (>30 seconds expected):
  • Multi-file changes, investigations, tests, feature work
  • Use 
    run_in_background: true
    → returns 
    task_id
Foreground tasks (<30 seconds):
  • Single-line fixes, simple queries

Monitoring Background Tasks

Token-efficient approach:
  1. Use 
    TaskOutput(task_id, block=true)
    to wait for completion
  2. Ignore TaskOutput's content (stdout redirected to progress file)
  3. Read summary file directly: 
    cat ~/.claude/codex/${CLAUDE_SESSION_ID}/summary-*.txt
The summary file contains only Codex's final message (token-efficient).
Progress checks (if needed before completion):
  • TaskOutput(task_id, block=false)
    - check if still running
  • tail -n 3 ~/.claude/codex/${CLAUDE_SESSION_ID}/progress-*.jsonl
    - last 3 events only
Do NOT read entire progress files or use 
tail -f
.

Report Result

Read summary:
bash
cat ~/.claude/codex/${CLAUDE_SESSION_ID}/summary-*.txt
Report format (≤5 bullets):
**Status:** {success/error/partial}
**Changed:** {files and changes}
**Validation:** {tests/linters}
**Risks:** {if any}
**Next:** {follow-up or "None"}

Examples

bash
# Simple fix
/codex fix the null pointer in utils/parser.ts line 42

# Feature work
/codex add rate limiting to the /api/submit endpoint

# Investigation (background)
/codex investigate why the CI build fails on arm64

# Model override
/codex --model o3 design a caching strategy

# Read-only
/codex --sandbox read-only review the auth implementation