The ultimate guide to designing legal prompts and contracts with AI

In the legal world, every word matters. Now that artificial intelligence has arrived on the scene, how we communicate with it also makes a difference. Legal prompting - the ability to formulate precise instructions for an AI to understand and solve complex legal tasks - has become a new core competency for in-house lawyers and managers.

In this article, we take you step-by-step through how to structure the perfect legal prompt, what elements to include, and how to get the most out of AI when drafting legal documents. We present a guide not only for those who are starting to experiment with AI in their legal practice but also for those who want to go further and master advanced prompt design techniques, with a clear goal: to create legal contracts faster, more accurately and more securely.

This article is also available in Spanish.

In this article, you will find:

1. What is a legal prompt, and why should you master it?
2. Structure of the legal prompt: the essential elements
3. Advanced prompt design techniques for the legal sector
4. How to create AI contracts step by step using legal prompting
5. Real examples of legal prompts to create contracts
6. Common mistakes when designing legal prompts and how to avoid them

1. What is a legal prompt, and why should you master it?

A prompt is the instruction you give to an AI to generate a response. In the legal context, it is the tool that determines whether you will get a useful answer or a result that lacks technical validity. Unlike a search engine, a generative AI does not work with simple keywords but with structured instructions that allow it to understand the target, the context and the legal constraints. A lawyer who knows how to design good prompts can obtain draft clauses, contracts or regulatory analysis in an agile way.

Advantages of applying effective legal prompting in your IA:

• Drastic reduction of drafting time.
• Improved accuracy and consistency of clauses.
• Optimisation of routine legal reviews.

You may be interested in: What is Legal Prompting? How to optimise its use in the legal sector?

2. Structure of the legal prompt: the essential elements

An effective legal prompt should have these key components:

1. Tone and purpose: What do you expect - a draft, a clause, a legal recommendation? What should the tone of the response be - informative and accessible, technical and specific?
2. Role of the AI: Ask it to act as a lawyer specialising in a particular area (e.g. ‘act as an expert in labour law in Spain’).
3. Full legal context: Include jurisdiction, type of contract, parties involved, legal relationship, type of service, sector, etc.
4. Format of expected output: ‘Write it as a clear clause in contractual style’.
5. Restrictions or exclusions: Ask to avoid unnecessary technicalities or ambiguous clauses.
6. Language and style: Formal, precise, technical, without redundancy.

3. Advanced prompt design techniques for the legal sector

Beyond the basic structure, there are techniques for designing prompts that allow higher-quality results. These are some of the most useful in the legal field:

A. Zero-shot prompting adapted to the legal environment

It consists of directly asking for what is needed without giving examples. It is quick but less precise in complex tasks.

Example:

 "Write a force majeure clause for a service contract between two companies in Spain".

B. Few-shot prompting

Examples are provided within the prompt so that the AI understands the expected style and structure.

Example:

 "Here is an example of an early termination clause. Now write a similar clause for the following case...".

This greatly improves consistency, especially if you are training the AI with the firm's own templates.

C. Chain-of-thought prompting

Ask the AI to explain its reasoning step by step before delivering the result.

Legal application: useful in regulatory analysis or to justify the inclusion of certain clauses.

Example:

 "Before drafting the clause, explain what elements it should include according to the Public Sector Contracts Law in Spain".

D. Prompt layering or modular prompting

Divide a complex contract into different parts and ask the AI to work clause by clause.

Example:

1. "Write the object clause of the contract".
2. "Now generate the duration and renewals clause.
3. "Now the confidentiality clause, adapted to the healthcare sector".

This approach is ideal for long contracts with high strategic value.

E. Prompt iteration and testing

Not all prompts work the first time. The job of a good legal prompter is to iterate, compare versions and adjust instructions until the most appropriate result is achieved. Don't be afraid to test, as this will lead to extraordinary results.

You may be interested in: How AI and automation transform contract negotiation

4. How to create AI contracts step by step using legal prompting

Step 1: Determine the structure of the contract

Although it is not an exact science, as a general rule, the more specificity, the better the results. Be clear about whether you need a complete contract or only certain clauses. Divide the contract into sections:

• Heading and parts
• Subject matter
• Duration
• Financial terms
• Rights and obligations
• Penalties
• Dispute resolution

Step 2: Choose the right prompting technique

• Use zero-shot prompting for standard contracts.
• Use few-shot or layering for complex contracts and contracts adapted to specific regulations.

Step 3: Draft the prompt

It's time for action. Include the following points in your prompt:

• The role of the AI: ‘Act as an expert lawyer in Spanish commercial law’.
• Clear instruction: ‘Draft the confidentiality clause adapted to the pharmaceutical sector’.
• Jurisdiction: ‘Must comply with Spanish Data Protection Law’.
• Format: ‘Contractual style, drafted in a single paragraph, without subheadings’.
• Tone: ‘Formal, direct, without unnecessary technicalities’.

Step 4: Check and refine

Pay attention because the following is one of the most important key points of this article: all results must be validated by a professional. Contrary to what it may seem, AI does not think and can make mistakes.

For this reason, you need to validate the result with your legal judgment. There will be cases where the result is not close to what you want, but don't give up. Try again: If the wording is not accurate, adjust the prompt and ask for generation again. You can combine chain-of-thought to understand how the AI has made its decisions.

5. Real examples of legal prompts to create contracts

Let's look at two examples of prompts that may seem simple to you but can give you very good results.

Service provision agreement with intellectual property clause

"Act as an expert intellectual property lawyer in Spain. Draft a contractual clause where Creative Agency X retains the copyright of the delivered work but grants Company Y an exclusive license to use it for 2 years, without assignment. Use technical legal language, contract clause format and no explanatory additions".

International labour contract

"Act as a specialist in Mexican labour law. Draft a contract term clause for an employee resident in Mexico, hired by a US company, including a 90-day probationary period under the Federal Labour Law. Use legal tone, contractual format, no added explanations".

Try Bigle Libra, the legal AI that will change the way you look at contract processes.

6. Common mistakes when designing legal prompts and how to avoid them

It is easy to make mistakes at the beginning, but practice makes perfect. Here are some mistakes to avoid when you start taking your first steps in legal prompting:

• ❌ Be too generic
  ✅ Be specific: type of contract, key clauses, jurisdiction.
• ❌ Do not define the expected result
  ✅ Ask for specific format, length and style.
• ❌ Do not include legal context
  ✅ Always state the jurisdiction, regulatory framework and status of the case.
• ❌ Blindly rely on the outcome of the IA
  ✅ The AI generates drafts. The lawyer should always review and validate.
• ❌ Use ambiguous or colloquial language
  ✅ Use clear and specific legal terms to avoid misinterpretation.
• ❌ Include too many instructions in a single prompt
  ✅ Divide complex tasks into separate, modular prompts by clauses or sections.
• ❌ Do not indicate the applicable law
  ✅ Always mention the country or regulatory framework to obtain legally relevant results.
• ❌ Forgetting the type of legal relationship between the parties
  ✅ Specify whether it is an employment relationship, commercial, civil, etc., in order to contextualise correctly.
• ❌ Do not indicate the public or addressee of the contract
  ✅ Clarify whether the contract is intended for large companies, self-employed, workers, etc.
• ❌ Do not check consistency between clauses generated
  ✅ Compare each part of the contract to avoid contradictions and ensure overall consistency.

Legal prompting, your new strategic skill

Mastering legal prompting allows you not only to get drafts of contracts in minutes but also to lead the digital transformation of the way your legal team works. It's not about replacing legal judgment, it's about expanding your capabilities, becoming more agile, focusing on the truly strategic, and letting AI assist you in your day-to-day work.

At Bigle, we have been helping legal departments to integrate legal AI and CLM effectively for years. If you want to take the next step and design smarter, faster and more secure contracts, we invite you to request a personalised demo and discover how our technology can revolutionise your day-to-day work.

Request a demo with an expert from Bigle