Codex Setup

Codex Setup & Configuration

Preflight check and ~/.codex/config.toml configuration helper for codex-advisor.

Mode Selection

Parse $ARGUMENTS:

| Input | Action | |-------|--------| | --status or no args | Run preflight + show current config | | --model MODEL | Set default model in config.toml | | --effort LEVEL | Set reasoning effort in config.toml | | Combined flags | Apply all settings |

Preflight Check

Check Codex CLI

which codex >/dev/null 2>&1 && codex --version || echo "NOT_INSTALLED"

If NOT_INSTALLED: "Codex CLI is not installed. Install: npm install -g @openai/codex"

Check Authentication

codex --version 2>&1

If output contains "not authenticated" or "OPENAIAPIKEY": "Authentication required. Run: codex login" If version prints normally: auth is likely OK (full verification happens on first real command).

Check Official Codex Plugin

CODEX_COMPANION=$("${CLAUDE_PLUGIN_ROOT}/scripts/resolve-companion.sh")

If exit code non-zero (plugin not found), guide the user through the full installation process:

1. Tell the user to run these commands in order (they must type these themselves since they are interactive CLI commands):

• /plugin marketplace add openai/codex-plugin-cc — adds the Official Codex marketplace
• /plugin install codex@openai-codex — installs the plugin from that marketplace
• /reload-plugins — activates the newly installed plugin

1. After the user completes the steps, re-run the companion check to verify.

Do NOT just print the steps and move on. Wait for the user to complete them.

If found, run setup check:

node "$CODEX_COMPANION" setup --json

Include the setup output in the status report.

Configuration Management

Read current config

cat ~/.codex/config.toml 2>/dev/null || echo "NO_CONFIG"

Set Model / Effort (--model, --effort)

Both flags are handled by one call. Empty string = no change for that field:

python3 "${CLAUDE_PLUGIN_ROOT}/scripts/apply-codex-config.py" "" ""

The script prints one line to stdout:

Model:  ->  | Effort:  -> 

Relay that line verbatim to the user — it shows before/after so they can confirm.

Model handling

• Accepts any slug your Codex account supports. Common slugs: gpt-5.5 (default xhigh), gpt-5.4, gpt-5.4-mini, gpt-5.3-codex, gpt-5.2.
• Alias: spark → gpt-5.3-codex-spark (subscription-gated; saved as-is).
• Slugs missing from ~/.codex/models_cache.json trigger an advisory warning to stderr but are saved. The cache reflects your account — gated or new models may be absent even when valid.
• When the slug IS in the cache and effort is left unset, the script prints a note showing that model's default_reasoning_level so the user can see what they'll get implicitly.

Effort handling

• Standard set for model_reasoning_effort: minimal, low, medium, high, xhigh. (none is only valid for plan_mode_reasoning_effort — passing it here triggers a warning.)
• Per-model support varies and is checked against the cache's supported_reasoning_levels. As of Codex CLI 0.125, every published model (gpt-5.5/5.4/5.4-mini/5.3-codex/5.2) supports [low, medium, high, xhigh] — minimal is currently unsupported on all of them. Out-of-set values warn but still save; Codex CLI will reject at runtime if the combination is unsupported.

The underlying script preserves other keys in config.toml (e.g. model_context_window) and writes atomically via a temp file.

Status Report

## Codex Setup Status

| Item | Status |
|------|--------|
| Codex CLI | version or NOT_INSTALLED |
| Authentication | OK or FAILED |
| Official Plugin | OK or NOT_INSTALLED (required) |

## Current Configuration (~/.codex/config.toml)

| Setting | Value |
|---------|-------|
| model |  |
| model_reasoning_effort |  |
| web_search |  |

These defaults apply to ALL Codex commands — both Official plugin and direct CLI.
To change: `/codex-setup --model gpt-5.5 --effort high`

Gotchas

• config.toml applies globally. Changes affect all Codex commands system-wide — Official plugin, direct CLI, and every codex-advisor skill. Warn the user when you mutate it.
• --effort is not a registered review/adversarial flag. handleReviewCommand valueOptions = [base, scope, model, cwd] (codex-companion.mjs:684). The only path that reaches the review code is the config.toml model_reasoning_effort key. --model IS honored as a flag in companion 1.0.4+ (startThread({ model }), lib/codex.mjs:56-66), but codex-advisor still routes it through config.toml for consistency across skills and so the value persists for the next session — same call shape on review/adversarial/rescue/verify/research. Every skill (review, adversarial, research, verify, rescue) accepts --model/--effort and writes via scripts/apply-codex-config.py — so the user doesn't have to call codex-setup separately.
• Don't create config.toml if the user only asked for status. apply-codex-config.py "" "" is safe (no-op, prints current values) but avoid it when just reporting — grep/cat is enough.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: LeeJuOh
• Source: LeeJuOh/claude-code-zero
• License: MIT

Install and usage instructions live in the source repository linked above.