How to make your own AI assistant in 2026: 6 simple steps, no code

To make your own AI assistant, pick one job you want help with, open a chatbot that lets you save instructions (Claude Projects, ChatGPT Projects or Gemini), write those instructions in plain English, add a few reference files, then test it with real questions until the answers come out right. You don't need to code. It's free on all three services, and I'd budget about 20 minutes for your first one.

By the end of this guide you'll have a working assistant that answers customer messages for a small dog-walking business, using that business's own price list. I put the steps together from Anthropic, OpenAI and Google help pages plus tech press coverage, as of early November 2026. Nobody at the site ran hands-on tests, so button names come from those pages (and they've changed a lot this autumn).

Before you start

A free account with Claude, ChatGPT or Gemini. This guide's worked example uses Claude, but the steps carry over.
A computer with a web browser. Setting things up is easiest on the web version.
One job you repeat often, such as replying to emails, planning meals or explaining homework.
One or two reference files, like a price list, a style guide or class notes.
Five real questions you already know the right answers to. You'll use them to test.

Watch out: custom GPTs, the old way to build an assistant in ChatGPT, are on their way out. On OpenAI's GPT help page, new GPT creation and publishing "are not available on personal ChatGPT accounts, including Free, Go, Plus, and Pro", and the retirement FAQ sets 11 December 2026 as the standard retirement date. So skip any tutorial that tells you to click Create in the GPT Store.

Step 1: Pick one job for your assistant

Start small. An assistant that does one thing well beats one that's meant to do everything, and it's far easier to test.

Write the job down as a single sentence with three parts: who it helps, what it does, and what a good answer looks like. Here's the sentence for this guide's example:

Help me reply to customer messages for my dog-walking business, using my real prices and policies, in a friendly tone, in under 120 words.

You should now have one sentence. If yours has the word "and" in it more than twice, I think it's probably two assistants.

Step 2: Choose where your assistant will live

All three big chatbots let you save instructions and files in one place, but they call it different things, and two of them are in the middle of a rename. Pick the one you already use.

Service	Feature to use	Free?	Notes (checked November 2026)
Claude	Projects	Yes, up to 5 projects	Instructions plus a knowledge base; paid plans add extra capacity for large files
ChatGPT	Projects	Yes, file limits depend on plan	Custom GPTs retire on 11 December 2026
Gemini	Gems, moving to skills	Gems yes; skills rolling out	Gems start migrating to skills on 17 November 2026
Any model, through an API	Your own code	Pay per use	Only if you can program

Claude's projects are "available to all users, including those with free Claude accounts" with free users capped at five. ChatGPT's project guide describes the same idea. Gemini is the messy one right now. Google's Gems page carries a banner saying Gems "will go away on personal Google accounts and automatically transition to skills", and 9to5Google reports that migration begins on 17 November 2026. Honestly, I'd hold off on building anything new in Gemini until skills settle down.

Tip: if you're not sure which chatbot to pick, our Claude vs ChatGPT comparison covers the differences in writing style and limits.

Step 3: Create the project and give it a name

In Claude, go to claude.ai/projects and click "+ New Project". Type a name and a short description. In ChatGPT, select New project in the sidebar instead.

One small catch. Going by Anthropic's setup steps, Claude "will not have access to these details", so the name and description are only for you. Don't put rules there; they belong in the instructions.

You should now see an empty project page with a space for instructions and files on the right.

Step 4: Write the instructions

Instructions are the heart of your assistant. They're applied to every chat in the project, so it's worth spending ten minutes here. Click "Set project instructions" in Claude, or open the three-dot menu and pick Project settings in ChatGPT. Then paste a template like this and fill in the brackets:

You are [role] for [who].

Your job: [the one-sentence job from Step 1].

Use the files in this project as your source of truth. If the answer isn't in the files, say you don't know and suggest what I should check.

Tone: [e.g. friendly, plain English, no jargon].

Format: [e.g. under 120 words, end with one clear next step].

Before answering, ask one clarifying question if the request is unclear.

OpenAI's GPT guidance (still useful advice, even with GPTs retiring) favours positive, concrete instructions over long lists of prohibitions, and suggests you "use headings and lists so priorities and steps are visually distinct." I'd agree; a wall of "never do this" lines tends to make answers stiff. For more ways to word instructions, see our guide to writing better prompts for ChatGPT, Claude and Gemini.

Step 5: Add your reference files

Files give your assistant facts; instructions tell it how to behave. Keep those two jobs apart.

In Claude, click the "+" button in the project knowledge area and upload your files. In ChatGPT you can upload PDFs, spreadsheets, docs and images, or paste text, and you can link Google Drive files or Slack channels too. Plain, text-heavy files work best: OpenAI warns that "complex layouts can make uploaded content harder" to use, and I'd guess the same is true across the board. A one-page price list in a simple document is ideal.

Watch out: in Claude, chats inside a project don't share context with each other unless the information is in the project knowledge base. If you settle something useful in one chat, add it to a file.

Step 6: Test it, fix it, and keep it up to date

Open a new chat inside the project and ask your five test questions one at a time. Compare each answer with the one you know is right. Does it use your real prices? Does it stick to the word limit?

When something's off, change one line of the instructions, then ask the same question again. Changing five things at once makes it hard to tell which edit helped. Once all five answers are right, you've got a working assistant, and you can start using it for real.

Worked example: a reply assistant for a dog-walking business

Say you run a small dog-walking business called Muddy Paws (an invented name for this example). You get the same twenty questions every week and want help drafting replies.

First, write a one-page file called muddy-paws-info and upload it to a new Claude project:

Prices: 30-minute walk $18, 60-minute walk $28, second dog from the same home +$8 per walk.

Hours: Monday to Friday, 7am to 6pm, no weekend walks.

Area: within 3 miles of the town centre, nowhere further out.

Cancellations: free with 24 hours' notice, otherwise full price.

New clients: free 15-minute meet-and-greet before the first walk.

Next, paste these project instructions:

You help me reply to customer messages for Muddy Paws, my dog-walking business.

Use muddy-paws-info as your only source for prices, hours and policies. Never invent a price or a discount. If a question isn't covered, write the reply but flag the gap at the end in [brackets] so I can check it.

Tone: warm, short, like a friendly neighbour. Sign off as "Sam at Muddy Paws".

Format: under 120 words. End with one clear next step for the customer.

Now test it with a message like this:

Hi! I have two spaniels and need someone Saturdays and maybe weekdays too. What would an hour cost?

A good reply should say there are no weekend walks, price a weekday hour for two dogs at $36 ($28 plus $8), offer the free meet-and-greet and stay under 120 words. If it quotes a Saturday price, your instructions aren't pointing firmly enough at the file, so add a line such as "Check the hours in muddy-paws-info before offering any time slot" and ask again.

That's the whole build. I like this example because you can check the maths in seconds.

Common mistakes and how to fix them

Putting rules in the project name or description. Claude can't see them, so move them into the instructions.
Asking it to do six jobs. Split it into separate projects, one per job.
Uploading messy scans. Retype the key facts into a short, plain document instead.
Testing with made-up questions. Use real messages you've already answered, so you know the correct reply.
Forgetting to update the files. When your prices change, replace the file, or the assistant will keep quoting the old ones.

Tips to get better results

Give it an example of a perfect answer. A single sample reply in your instructions often does more than a paragraph describing your tone.

Tell it what to do when it doesn't know. The line "flag the gap in [brackets]" is probably the most useful one in the worked example, because it stops the assistant guessing at prices.

Rerun your test questions after every edit. Two minutes.

And keep personal or sensitive details out of your files unless you've read the service's privacy settings. On Claude's plans page, model training is listed as "Opt-out" on every consumer plan, so check that setting first.

Next steps

Once your first assistant works, you can go further in two directions. If you want it to take actions (send emails, update a spreadsheet), you're building an agent rather than an assistant, and our guide on how to create an AI agent walks through that with Zapier. If you'd like to put an assistant on your website for customers, look at our roundup of AI chatbot builders.

Developers can build one from scratch through an API and pay per token. On Anthropic's API price list, Claude Sonnet 4 costs $3 per million input tokens and $15 per million output tokens. Our list of free AI coding assistants can help with the first script.

FAQ

How to make AI assistant?

Choose one job and create a new project in Claude or ChatGPT. Paste instructions that describe the role, tone and format you want, upload a file with the facts it should use, then test it with real questions, adjusting one instruction at a time until the answers are right. It's free.

Can I create my own AI assistant for free?

Yes. Claude lets free users create up to five projects, and ChatGPT Projects are open to signed-in users. Gemini's Gems, free on every plan until now, are moving to skills from 17 November 2026. Paid plans mostly add higher limits. I doubt a first assistant needs them.

How much does it cost to build an AI assistant?

A no-code assistant inside Claude or ChatGPT costs nothing on the free plans. If you code your own, you pay per token, at the API rates shown under Next steps. Custom AI assistant development by an agency is a different matter: quotes vary so widely that I'd get at least three before signing anything, and ask each one what the no-code version can't do.

Can I still make a custom GPT?

Not on a personal account, and I wouldn't bother anyway. Custom GPTs are scheduled to retire on 11 December 2026, with existing ones migrating to plugins. Use ChatGPT Projects for anything new.

Do I need to know how to code?

No. Everything in Steps 1 to 6 happens in a normal chat window. Coding only matters if you want the assistant inside your own app or website.