You have read that AI agents can sort your requests, prepare your follow-ups or keep track of your files, and you are wondering where to actually start. Most entrepreneurs get stuck at the same point: they know what they would like to delegate, but not how to turn the idea into an agent that works. The good news is that creating an AI agent no longer requires a single line of code. This guide shows you, step by step, how to build one with Claude, ChatGPT, Mistral or Copilot, with a complete example and instructions you can copy.
AI agent or AI assistant: what is the difference?
An AI assistant answers when you ask a question. You write, it drafts, you copy the result. Every exchange starts with you.
An AI agent receives a mission, rules and access to certain tools. It chains several steps to reach a result: read the emails in a folder, extract the useful information, store it in a spreadsheet, prepare a reply. It can also be triggered at a set time or when a new item arrives. It acts within the framework you have defined: what it may do, what it must never do, and when it must ask for your approval.
In practice, the line is getting thinner: today's assistants (Claude, ChatGPT, Mistral, Copilot) all let you turn a conversation into a reusable agent. If you first want to identify which tasks to hand over to an agent, our article AI agents: automate your tasks covers that. Here, we move on to building.
Why create an AI agent as an entrepreneur
Entrepreneurs repeat the same tasks every week: answering quote requests, following up, filing documents, preparing a weekly review. Each takes only a few minutes, but together they often add up to several hours a week.
A well-built agent brings three things:
- Hours saved: in the order of one to three hours a week for a first agent, depending on the volume of the task.
- Consistency: the task is done the same way every time, with your criteria.
- Less mental load: you no longer have to remember what needs a follow-up or filing.
How to create an AI agent: the 6-step method
Whatever tool you choose, building an agent always follows the same steps. This is the tutorial to remember; the tool comes second.
- Pick one repetitive task. It should come back at least every week, follow a stable logic and have a result you can check. Example: "qualify the quote requests received by email".
- Describe the task as you would to a new team member. What information it receives, what it must produce, in what format and within what time.
- Set the rules. What it may do on its own, what it must submit to you, what it must never do (send an email to a client without approval, for example).
- Provide reference documents. Your offer, your prices, three examples of successful replies. This is what separates a generic agent from one that works the way you do.
- Connect only the tools it needs. Inbox, calendar, shared folder or spreadsheet: only give access to what the task requires.
- Test on ten real cases, then adjust. Compare its results with yours, fix the instructions, and repeat until you have almost nothing left to correct.
An AI agent example: the quote request qualifier
Here are the complete instructions for an agent you can adapt to your business:
"You are the sales assistant of [company name]. For each new quote request, extract: the contact's name, the company, the need, the budget if stated, the requested deadline. Classify the request as "priority", "to review" or "out of scope" according to the criteria in the "Ideal clients" document. Prepare a draft reply in my tone, based on the examples provided. Never send a message yourself: present the draft to me for approval. If a piece of information is missing, flag it instead of making it up."
Hours saved: often one to two hours a week if you receive several requests a day.
How to create an AI agent with Claude
Claude, developed by Anthropic, offers several building blocks to create an agent without coding:
- Projects: a space where you store your reference documents and permanent instructions. It is the foundation of your agent. We cover this feature in our article on Claude Projects use cases.
- Skills: reusable procedures that Claude applies automatically when a task matches.
- Connectors: access to your inbox, calendar or online documents.
- Cowork, included in paid plans: Claude carries out the task end to end, on your files and tools, and can run it again at regular intervals with scheduled tasks. Our Claude Cowork tutorial explains how it works.
The approach: create a "Quote agent" Project, paste the instructions above, add your documents, connect your inbox, then test. Once the result is reliable, hand the execution over to Cowork and schedule it every morning.
Creating an AI agent in ChatGPT, with Mistral or with Copilot
In ChatGPT
In September 2026, OpenAI announced the gradual retirement of custom GPTs, replaced by plugins that bundle skills (your reusable instructions) and connected apps. The creation of new GPTs is being phased out, and existing GPTs are scheduled to stop running on December 11, 2026: their instructions and files can be migrated to a plugin. If you are starting from scratch, build your agent directly as a plugin, available on paid plans, and check the conditions of your subscription in OpenAI's help center.
With Mistral
Mistral's assistant, formerly Le Chat, is now called Mistral Vibe. Its Work mode chains multi-step tasks across your connected tools (email, documents, project management), asks for your approval before sensitive actions such as sending an email, and can schedule a task daily or weekly. Your procedures become reusable skills. It is a good option if you prefer a European provider.
With Copilot
If your business runs on Microsoft 365, the agent builder is built into Copilot: choose "New agent", describe what it should do, or start from a template, then adjust its configuration. According to Microsoft's documentation, agents based only on instructions or public data do not incur extra cost, while those using your company's data are billed based on usage. Check the terms of your subscription.
A ready-made agent for every area of your business
The Agents IA Pro bootcamp helps you set up your agentic system: admin, emails, sales, research, management and marketing. You delegate your time-consuming tasks to agents that follow your rules, without coding.
Watch the free Agents IA Pro trainingCreating a free AI agent: what is possible
You can start without paying, as long as you accept a few limits. At the time of writing (September 2026):
- Claude Free gives access to skills, memory and connectors. Projects and Cowork, however, require a paid plan.
- Mistral offers a free plan to try its assistant, with usage limits.
- Copilot lets you create simple, instruction-based agents without an extra license if you have a Microsoft 365 work account.
- Automation tools such as Make or n8n have a free plan or a self-hosted version. Our n8n, Make and Zapier comparison helps you choose.
Our advice: build and test your first agent for free. As soon as it saves you an hour a week, the subscription easily pays for itself. Plans change often: always check the current terms on each provider's website.
Which AI agent should you choose?
The right tool mostly depends on the environment you already work in:
- You write a lot and work on documents: Claude, for its writing quality, and Cowork for execution.
- You already use ChatGPT every day: stay in its ecosystem and use plugins.
- You want a European provider: Mistral Vibe.
- Your business runs on Microsoft 365: Copilot, for its close ties with Outlook, Teams and SharePoint.
- Your task links several apps without intervention (form, CRM, invoicing): an automation tool such as Make or n8n, where AI steps in at a specific stage. Our article on automating emails with Make and Zapier shows an example.
Do not look for the perfect tool: the six-step method works everywhere. Your instructions and reference documents move easily from one tool to another.
Mistakes to avoid
Starting with an agent that does everything. An "executive assistant" agent handling emails, calendar, invoices and prospecting will disappoint. One agent per task, then a second, then a third.
Granting too much access. Every connected tool is an open door. Limit access to what is strictly necessary and avoid sharing personal data without a reason. Also check the privacy settings of each tool.
Removing approval too early. Until the agent has proven reliable over several weeks, everything that goes to a client should go through you.
Writing vague instructions. "Answer clients" is not enough. Specify the format, the tone, the special cases and what to do when in doubt.
Never reviewing the results. You supervise an agent like a team member: a regular look at what it produces is enough to spot a drift.
FAQ: the most common questions about creating an AI agent
Do you need to code to create an AI agent?
No. Claude, ChatGPT, Mistral and Copilot let you create an agent by writing instructions in plain language and connecting your tools from their interface. Code is only useful for very specific needs.
Can you create an AI agent for free?
Yes, for a simple first agent. Free plans are enough to build and test. For daily use or advanced features such as Cowork, a paid plan becomes necessary.
How long does it take to create an AI agent?
Often one to two hours for a first version, then a few adjustments over one to two weeks of real use before it is reliable.
Can an AI agent make decisions for me?
An agent acts within the framework you set. You decide what it may do on its own and what it must submit to you. For anything that commits your business to a client, keep a human approval step.
How do you set up several agents working together?
Start with one reliable agent, then add one per area of your business. That is exactly what we build with you in the Agents IA Pro bootcamp, with a ready-to-import agent for each area.