---
title: OpenAI Codex CLI Plugin — Cromus Workflow Intelligence
description: Cromus ships an HTTP MCP plugin for OpenAI Codex CLI exposing six deterministic Workflow Intelligence tools callable from the terminal. One config block in ~/.codex/config.toml — no local server required.
canonical: https://cromus.ai/codex-plugin
source_html: https://cromus.ai/codex-plugin
---

# OpenAI Codex CLI Plugin

> Six deterministic Workflow Intelligence tools — callable from your terminal via OpenAI Codex CLI. One config block to install.

Cromus ships an HTTP MCP plugin for OpenAI Codex CLI that exposes the full Workflow Intelligence toolkit as standard MCP tools callable from the terminal. Install is a single configuration block in `~/.codex/config.toml`.

---

## Installation

Add the following block to `~/.codex/config.toml`:

```toml
[[mcp_servers]]
name = "cromus"
type = "http"
url = "https://mcp.cromus.ai/mcp"

[mcp_servers.headers]
Authorization = "Bearer YOUR_CROMUS_API_KEY"
```

Replace `YOUR_CROMUS_API_KEY` with your key from Cromus workspace settings. Reload Codex — the six tools are immediately available.

---

## The six tools

| Tool | What it does |
|------|-------------|
| `score_skill` | Score a SKILL.md — AI-readiness, completeness, Croms™ waste |
| `simulate_cost` | Project per-run and monthly cost across 5 modes and 62+ models |
| `validate_skill` | Validate a SKILL.md against the open spec |
| `validate_ethos` | Validate an ETHOS.md behavioral governance file |
| `validate_memory` | Validate a MEMORY.md portable memory spec |
| `reality_check_summary` | Summarize reality-check loop results for a workflow |

All six tools are **deterministic** — zero LLM calls, zero external API dependencies. The same SKILL.md always produces the same scores.

---

## Same endpoint, same keys

The Codex CLI plugin uses the same `https://mcp.cromus.ai/mcp` endpoint and the same API keys as the Claude Cowork connector. If you already use Cromus in Cowork, your existing key works for Codex CLI without any additional setup.

---

## No-retention contract

Inputs passed to any of the six tools are used only to compute the response — not stored, logged for training, or retained after the request completes.

---

## Example usage

```bash
# Inside a Codex session, after loading the plugin:
cromus.score_skill --file ./skills/customer-support.md

# Output:
{
  "readiness_score": 87,
  "label": "AI Ready",
  "croms_estimate": 142,
  "top_findings": [
    "Missing retry policy for step 3",
    "Step 2 could use a Lightweight model (currently Frontier)"
  ]
}
```

---

## Related pages

- [Claude Cowork MCP Connector →](/cowork-connector)
- [Pre-Execution Governance →](/pre-execution-governance)
- [SKILL.md Validator →](/validator/skill)
- [Workflow Intelligence as a Service →](/workflow-intelligence-as-a-service)