Ever since OpenAI opened up the ability to create custom GPTs, many legal professionals have asked themselves: can I build one that knows my job, my contracts, my habits? The answer is yes. And it's simpler than you might think.
What exactly is a custom GPT?
A custom GPT is a version of ChatGPT that you configure yourself with your own instructions and your own documents. In practice, you tell it how to behave, what tone to adopt, which topics it should master — and you can even give it files to use as a knowledge base.
For a legal professional, this means that instead of asking ChatGPT generic questions and getting vague answers about French law, you can have an assistant that knows your context, your types of contracts and your usual issues.
Step 1: Define your GPT's purpose
Before you start, ask yourself a simple question: what will I use it for on a daily basis? A GPT that does everything does nothing well. A specialized assistant with a precise scope is better.
A few concrete examples:
- •Clause review: a GPT that analyzes your contract clauses and suggests balanced rewordings.
- •Internal legal FAQ: an assistant that answers your teams' recurring questions based on your internal documentation.
- •Drafting legal emails: a GPT that helps you formulate professional and precise responses.
- •Risk analysis: an assistant that identifies points of concern in a given contract or situation.
Step 2: Write the instructions
This is the heart of your GPT. The instructions tell it who it is and how it should behave. The more precise you are, the better it will be.
Example instructions for a contract review GPT:
You are a legal assistant specialized in French contract law.
When a clause is submitted to you, you must:
1. Identify potential imbalances
2. Propose a more balanced alternative version
3. Explain the legal risks in plain language
You are addressing in-house legal professionals. Be precise and concise.
Never give a definitive opinion — always remind that the final analysis is up to the lawyer.
A few tips: define the tone (formal, educational, direct), the scope (French law only, business law, GDPR...) and the limits (what it should not do, such as giving a definitive legal opinion).
Step 3: Feed the knowledge base
This is where it gets interesting. You can upload files (PDF, Word, text) so your GPT can use them as reference. For a legal professional, this could be:
- •Your standard contract templates
- •Your internal clause library
- •Your legal department's internal procedures
- •Case law or doctrine notes
- •The legal FAQ you maintain for business teams
Warning: files you upload to ChatGPT are stored on OpenAI's servers. Avoid uploading confidential documents or personal data. For secure use with sensitive data, solutions like Juriview integrate AI directly within an environment hosted in France.
Step 4: Test and refine
Once your GPT is created, test it with real cases. Submit clauses you've already analyzed, ask questions you know the answer to. You'll quickly see where it excels and where it falls short.
Don't hesitate to iterate on the instructions. Add clarifications, correct behaviors you don't like. A good custom GPT is the result of several successive adjustments, not a perfect configuration on the first try.
Limitations to know
Let's be honest: a custom GPT is a great tool for saving time, but it has its limits.
- •It can hallucinate: invent legal references or law articles that don't exist. Always verify.
- •It doesn't replace the lawyer: it assists, it speeds things up, but final judgment remains human.
- •Confidentiality: your data passes through OpenAI's servers. For sensitive documents, prefer a solution hosted in France.
- •No automatic updates: if your documentation changes, you need to remember to update your GPT's files.
Want to go further?
A custom GPT is a good start. But it remains an isolated tool: it doesn't connect to your files, doesn't create tickets, doesn't track your deadlines and doesn't fit into your daily workflow.
This is exactly why we created Juriv'IA, the AI built into Juriview. It works on the same principle — it learns from your data — but it is directly embedded in your workspace: in every ticket, every contract, every file. And most importantly, your data stays hosted in France.
If you like the concept of a custom GPT but want something more integrated and secure,let's talk for 30 minutes to see how Juriview can adapt to your organization.