Codex

CodeX — Your Codex Coding Partner

Delegate coding execution to Codex CLI. CodeX turns clear plans into working code.

Critical rules

• ONLY interact with CodeX through the bundled shell script. NEVER call codex CLI directly.
• Run the script ONCE per task. If it succeeds (exit code 0), read the output file and proceed. Do NOT re-run or retry.
• Do NOT read or inspect the script source code. Treat it as a black box.
• ALWAYS quote file paths containing brackets, spaces, or special characters when passing to the script (e.g. --file "src/app/[locale]/page.tsx"). Unquoted [...] triggers zsh glob expansion.
• Keep the task prompt focused. Aim for under ~500 words. Describe WHAT to do and key constraints, not step-by-step HOW. CodeX is an autonomous agent with full workspace access — it reads files, explores code, and figures out implementation details on its own.
• Never paste file contents into the prompt. Use --file to point CodeX to key files — it reads them directly. Duplicating file contents in the prompt wastes tokens and adds no value.
• Don't reference or describe the SKILL.md itself in the prompt. CodeX doesn't need to know about this skill's configuration.

How to call the script

The script path is:

~/.claude/skills/codex/scripts/ask_codex.sh

Minimal invocation:

~/.claude/skills/codex/scripts/ask_codex.sh "Your request in natural language"

With file context:

~/.claude/skills/codex/scripts/ask_codex.sh "Refactor these components to use the new API" \
  --file src/components/UserList.tsx \
  --file src/components/UserDetail.tsx

Multi-turn conversation (continue a previous session):

~/.claude/skills/codex/scripts/ask_codex.sh "Also add retry logic with exponential backoff" \
  --session <session_id from previous run>

The script prints on success:

session_id=<thread_id>
output_path=<path to markdown file>

Read the file at output_path to get CodeX's response. Save session_id if you plan follow-up calls.

Decision policy

Call CodeX when at least one of these is true:

• The implementation plan is clear and needs coding execution.
• The task involves batch refactoring, code generation, or repetitive changes.
• Multiple files need coordinated modifications following a defined pattern.
• You want a practitioner's perspective on whether a plan is feasible.
• The task is cost-sensitive and doesn't require deep architectural reasoning.
• Writing or updating tests based on existing code.
• Simple-to-moderate bug fixes where the root cause is identified.

Workflow

1. Design the solution and identify the key files involved.
2. Run the script with a clear, concise task description. Tell CodeX the goal and constraints, not step-by-step implementation details — it figures those out itself. For discussion, use a question-oriented task with --read-only.
3. Pass relevant files with --file (2-6 high-signal entry points; CodeX has full workspace access and will discover related files on its own).
4. Read the output — CodeX executes changes and reports what it did.
5. Review the changes in your workspace.

For multi-step projects, use --session <id> to continue with full conversation history. For independent parallel tasks, use the Task tool with run_in_background: true.

Options

• --workspace <path> — Target workspace directory (defaults to current directory).
• --file <path> — Point CodeX to key entry-point files (repeatable, workspace-relative or absolute). Don't duplicate their contents in the prompt.
• --session <id> — Resume a previous session for multi-turn conversation.
• --model <name> — Override model (default: uses Codex config).
• --reasoning <level> — Reasoning effort: low, medium, high (default: medium). Use high for code review, debugging, complex refactoring, or root cause analysis.
• --sandbox <mode> — Override sandbox policy (default: workspace-write via full-auto).
• --read-only — Read-only mode for pure discussion/analysis, no file changes.