How to Build a Custom AI Assistant You Actually Own

If you have built a custom GPT, you already know the problem. It works, people like it, and it isn't yours. It lives inside someone else's platform. You cannot put it on your own domain, you cannot build a subscriber list from it, and you cannot charge your own price for it.

So I built a free plugin that makes you one you do own. Same idea as a custom GPT — your instructions, your knowledge, your personality — except it runs as a real web app on your own domain, and people can subscribe to it.

Here is the whole thing, start to finish. It takes about an hour.

Step 1 — Set up

Download VS Code (free) and install the Claude Code extension, or use the Claude Code desktop app — whichever you prefer. Then create a new empty folder for your assistant and open it in Claude Code.

That folder matters more than it sounds like it should. Start somewhere empty so your assistant isn't being built on top of another project.

Step 2 — Install the plugin

Paste these two lines into Claude Code, one at a time.

Add the marketplace

/plugin marketplace add ejacques1/leveraging-ai-skills

Install the plugin

/plugin install leveraging-ai@leveraging-ai-skills

You only do this once. It stays installed after that.

Step 3 — Restart Claude Code

Close it and open it again. This is the step people skip, and the plugin will not appear until you do it.

Step 4 — Tell it what you want

Then type this

build me a custom AI assistant

It asks four quick questions: what your assistant is about, how it should behave, what it should look like, and whether you want it behind a paywall. Answer them in plain English. Then it builds.

Notice what you are not doing. You are not writing prompts, copying boilerplate, or wiring anything together. The plugin carries the instructions.

Step 5 — Add your key

It stops and asks for an Anthropic API key, and opens a text file for you so you are not hunting for where it goes.

Go to console.anthropic.com, open API Keys, choose Create Key, copy it, paste it into the file it opened, and save.

That key is what you pay Anthropic on. It is pennies while you are testing.

Step 6 — Watch it reply

It sends a real message and shows you the answer. This is the part I care about most: it will not tell you it is finished until you have actually seen it work.

Now open assistant-instructions.md. That file is your assistant. Rewrite any line, save it, send another message, and watch the personality change. Drop documents into the knowledge folder and it starts using them.

The building is the easy part now. Where people get stuck is the deploy, the API keys, and knowing which button to press.

Step 7 — Put it online

When you like how it answers, say so.

Deploy it

put it online

It walks you through getting it onto your own domain. And if you asked for a paywall, that is the last step: a login and a Stripe subscription, so only paying members can use it.

What you end up with

1. An assistant on your own domain, not inside someone else's platform.
2. Your instructions and your knowledge, in files you can edit any time.
3. Your name on it, and your branding.
4. A way to charge for it, if you want one.

Nothing is held back. The paywall step is included in the free plugin.

One thing I will be straight with you about: the building really is the easy part now. Where people get stuck is the deploy, the API keys, and knowing which button to press. That is not a you problem. It is just the part nobody explains.

If you get stuck, come get help

That is what the community is for. You get daily support, and we meet live every Friday at noon — and the deploy, the API keys and the which-button-do-I-press moments are exactly what we work through together.

Come build AI-powered web apps with me: join the community.