Using Skills with Codex

Overview

Compound Skills work with OpenAI’s Codex App. Skills are structured markdown files that guide an AI through a legal analysis step by step — the same format works whether you run them in Claude, Codex, or another markdown-aware tool. If you already use Codex for research or drafting, adding Skills means you can run repeatable, structured legal reviews without writing new prompts every time.

This guide covers setup, running analyses, and organizing your workspace for ongoing use.

Setting Up Skills in Codex

Getting a Skill into Codex takes less than a minute.

Step 1 — Download the Skill file. Browse the Compound Skills library and download the .md file you need — for example, terms-and-conditions-check.md or employment-reference-analysis.md.

Step 2 — Open the Codex App and navigate to your workspace. If you do not have one yet, create a new workspace — the project folder where Codex looks for files and context.

Step 3 — Add the Skill file to your project files. Drag the .md file into your workspace or use the file upload interface. A skills/ folder works well.

Step 4 — Confirm Codex can see it. Codex reads markdown files in the workspace automatically. It parses their structure — headings, numbered steps, decision criteria — and follows those instructions when you reference the file. No plugins or extensions needed.

Running an Analysis

With the Skill in your workspace, you are ready to analyze a document.

1. Upload or paste the document you want reviewed — an AGB, an employment reference, a data processing agreement, or any text the Skill is designed to handle.

2. Prompt Codex to apply the Skill. Be explicit about which Skill to use. For example:

   • “Use the Terms & Conditions Check skill to review this AGB document. Flag any clauses that deviate from standard consumer protection requirements under German law.”
   • “Apply the Employment Reference Analysis skill to decode this Arbeitszeugnis. Tell me what each phrase actually means and rate the overall assessment.”
   • “Run the Data Processing Agreement Review skill against this Auftragsverarbeitungsvertrag. Check GDPR compliance and highlight missing provisions.”

3. Review the output. Each section maps to a step defined in the Skill file. If the Skill has five analysis steps, you get five corresponding sections — making it easy to verify each part independently.

4. Ask follow-ups. Drill into specific findings — ask Codex to elaborate on a flagged clause, suggest alternative language, or compare against a specific legal standard.

Using AGENTS.md for Persistent Skills

If your Codex workspace uses an AGENTS.md file, you can register Skills there so Codex knows about them without you mentioning them in every prompt. This is useful when you work with multiple Skills across practice areas.

Here is an example AGENTS.md configuration:

## Available Skills

### Contract Law
- Terms & Conditions Check: See skills/contract-law/terms-and-conditions-check.md
- NDA Review: See skills/contract-law/nda-review.md

### Employment Law
- Employment Reference Analysis: See skills/employment/employment-reference-analysis.md

### Data Protection
- GDPR Data Processing Agreement: See skills/data-protection/dpa-review.md

## Instructions
When a user uploads a legal document, suggest the most relevant Skill
from the list above. Always apply the full Skill workflow before summarizing.

With this in place, you can simply upload a document and say “Review this” — Codex will match it to the right Skill based on context.

Workspace Organization

A clean folder structure keeps your Skills manageable as the collection grows:

my-legal-workspace/
├── AGENTS.md
├── skills/
│   ├── contract-law/
│   │   ├── terms-and-conditions-check.md
│   │   └── nda-review.md
│   ├── employment/
│   │   └── employment-reference-analysis.md
│   └── data-protection/
│       └── dpa-review.md
├── documents/
└── outputs/

If you use Git, track your Skills alongside your projects for change history, team sharing, and easy rollback.

Best Practices

Be explicit with your prompts. The same principles that work with Claude apply here. Provide the full document — not an excerpt — and tell Codex exactly which Skill to apply.

Batch-process when it makes sense. Codex can apply the same Skill to multiple documents in sequence. If you have a stack of employment references to decode or vendor contracts to review, upload them together and run the Skill against each one.

Fork and customize Skills for your firm. Library Skills are starting points. If your firm has specific standards — particular clauses you always check in NDAs, or data protection requirements beyond the GDPR baseline — fork the Skill and add your own criteria. Just add a heading or checklist item.

Always verify AI output against your professional judgment. Skills provide structure and speed, but they do not replace legal analysis. Treat every AI-generated review as a first draft. Check the reasoning, confirm the citations, and apply the context that only you as the practicing lawyer can bring.