How to Set Up Codex Skills from Claude Code Commands in ai-berkshire

To set up Codex skills from Claude Code commands in ai-berkshire, clone the repository and run ./scripts/install-codex-skills.sh, which automatically converts the Markdown files in skills/ into Codex-compatible packages and installs them to $HOME/.codex/skills.

The ai-berkshire repository maintains investment-research commands as Claude Code-compatible Markdown files under skills/. When you set up Codex skills from these Claude Code commands, the repository's automation scripts generate platform-specific packages and configure your local Codex environment to recognize them.

Step-by-Step Installation Process

Clone the Repository

Start by cloning the ai-berkshire repository to access the skill definitions and automation scripts.

git clone https://github.com/xbtlin/ai-berkshire.git
cd ai-berkshire

Generate and Install Codex Skills

Run the main installation script to convert Claude Code commands into Codex skills. This script calls scripts/sync-codex-skills.py internally to parse the Markdown frontmatter and body from skills/*.md, then copies the generated packages to your Codex skills directory.

./scripts/install-codex-skills.sh

By default, the script installs skills to $HOME/.codex/skills, creating subdirectories like ~/.codex/skills/investment-research/ containing SKILL.md and supporting assets.

Install Optional Slash-Command Prompts

For a Claude Code-like slash command interface (/prompts:investment-research), install the optional prompt wrappers.

./scripts/install-codex-prompts.sh

This copies plain-text prompt files from codex-prompts/ into your Codex configuration, enabling invocation via the /prompts: prefix.

Restart Codex

After installation, restart your Codex CLI or reload your IDE's Codex extension to load the newly installed skills. You can then invoke skills by name (e.g., investment-research) or via slash prompts.

Understanding the Sync Architecture

The ai-berkshire repository uses a single source of truth pattern where skills/*.md files serve as the canonical definitions.

Source Files in skills/

Each Claude Code command lives as a self-contained Markdown file with YAML frontmatter. For example, skills/investment-research.md contains the command definition, description, and execution logic.

The Sync Script

scripts/sync-codex-skills.py traverses the skills/ directory and generates Codex-compatible structures under codex-skills/<skill-name>/SKILL.md. The script handles:

• Parsing Markdown frontmatter (name, description)
• Converting body content to Codex skill format
• Copying referenced assets and tool scripts

Tooling Integration

Helper scripts in tools/ (such as financial_rigor.py) support skill execution. The installation script automatically marks these as executable (chmod +x) during the install process, ensuring Codex can invoke them without additional setup.

Adding Custom Commands

To create a new command available in both Claude Code and Codex:

1. Create a new Markdown file in skills/:

cat > skills/my-analysis.md <<'EOF'
---
name: my-analysis
description: Runs custom financial analysis
---

# My Analysis

This skill performs automated SEC filing analysis.

**Usage**

```text
my-analysis <ticker>

EOF

2. Regenerate and reinstall:

```bash
./scripts/install-codex-skills.sh

3. Invoke in Codex:

my-analysis AAPL

Code Examples

Full Setup Workflow

# Clone repository

git clone https://github.com/xbtlin/ai-berkshire.git
cd ai-berkshire

# Install Codex skills and prompts

./scripts/install-codex-skills.sh
./scripts/install-codex-prompts.sh

# Verify installation

ls ~/.codex/skills/

Updating Skills After Changes

When you modify files in skills/, you must rerun the sync process to update Codex:

# Edit the source

vim skills/investment-research.md

# Sync changes

./scripts/install-codex-skills.sh

Using Slash Prompts

If you installed the optional prompts, access them via:

/prompts:investment-research Tesla

This forwards to the underlying investment-research skill with the provided argument.

Summary

• Source of truth: The skills/ directory contains canonical Claude Code command definitions in Markdown format.
• Generation: scripts/sync-codex-skills.py converts these Markdown files into Codex-compatible skill packages.
• Installation: scripts/install-codex-skills.sh handles both generation and installation to $HOME/.codex/skills.
• Optional UI: scripts/install-codex-prompts.sh enables slash-command syntax similar to Claude Code.
• Synchronization: Always rerun the install script after editing skills/*.md to keep Codex updated.

Frequently Asked Questions

What is the difference between Claude Code commands and Codex skills?

Claude Code commands are defined as Markdown files in skills/ with specific frontmatter and instructions. Codex skills are the same logical commands packaged into a directory structure (codex-skills/<skill>/SKILL.md) that the Codex CLI recognizes. The scripts/sync-codex-skills.py file bridges these formats automatically.

Do I need to reinstall Codex skills after editing the Markdown files?

Yes. The skills/ directory is the canonical source, and changes are not automatically synced to Codex. You must run ./scripts/install-codex-skills.sh after any modification to skills/*.md to regenerate the Codex packages and copy them to $HOME/.codex/skills.

Where are the generated Codex skills stored locally?

By default, the installation script copies generated skills to $HOME/.codex/skills/ (or $CODEX_HOME/skills if that environment variable is set). Each skill appears as a subdirectory containing SKILL.md and any supporting tool scripts from the tools/ directory.

How do I add a new command to both Claude Code and Codex?

Create a new Markdown file in skills/ with the appropriate frontmatter (name and description) and command body. After saving, run ./scripts/install-codex-skills.sh. The new command becomes available immediately in Codex after restart, and will work in Claude Code if you have the repository mounted as a project-specific skill.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}