A small, safe chat agent for your business, with a cost cap and a person to take over.
What this is
Eight small steps with copyable prompts: the brief, a safe key, the build, six checks, a cost cap, publishing and a security check.
Who it is for
Business owners who read How AI agents work and want to try one.
What you will get
A working chat agent that answers from your facts and stops at a spending limit.
Time
About 85 minutes
You need
A tool that builds projects (Claude Code, Cursor or similar)
An account with one AI company, with a spending limit set
About an hour and a half
Your path: Build the agent, start to finish
1
Step 1 of 8Time: 8 min
Let an AI interview you
Why: The AgentAn agent is an AI that does not only talk: it picks steps, uses tools and works until a job is done. can only be as good as the facts you give it.
A good agent starts with a clear one-page brief. An AI can write it by asking you questions.
What to do
Press Copy and paste it in a chat app.
Answer each question with true facts.
Interview me and write the brief
Interview me to write a one-page brief for an AI agent for my business. Ask ONE question at a time, in plain words. Ask about: what my business does, the 10 questions customers ask most (with the true answers), what the agent must never do or promise, when a person should take over, and how much I am willing to spend each month. After my answers write the brief with these headings: Job, Facts it may use, Never do, Hand over when, Monthly cost cap. Use only what I told you. Do not invent facts.
You should see: A short brief with five headings: Job, Facts, Never do, Hand over when, Cost cap.
Stuck?
I do not know the answers?
Write what customers ask you most, and answer them yourself.
It invents facts?
Say: Use only what I told you.
Build your first AI agent, step by step
☐ Let an AI interview you
Press Copy and paste it in a chat app.
Answer each question with true facts.
You should see: A short brief with five headings: Job, Facts, Never do, Hand over when, Cost cap.
☐ Get an AI key and set a spending limit
Make an account with the AI company you chose and make a key.
In its dashboard, set a monthly spending limit.
Keep the key in a safe note. Do not paste it in a chat.
You should see: A key saved safely, and a limit shown in the dashboard.
☐ Paste the first-agent prompt
Open a tool that builds projects, like Claude Code or Cursor.
Press Copy, paste, change the part in square brackets, and send.
Reply defaults to its five questions.
You should see: The tool shows an 8-line plan and waits for your go.
☐ Put the key in the secret file
Create the file .env.local in the project folder.
Type the name below, then paste your key after the equals sign. Do it in the file, not in the chat.
You should see: The file has one line with the name and your key. The agent starts without a key error.
☐ Run the six checks
Press Copy and send it in the same chat.
Try the checks yourself on your phone too.
You should see: A list: pass or fail for each of the six checks.
☐ Test the cost cap
Press Copy and send it.
Chat until the friendly stop message appears.
You should see: The agent stops, shows a friendly message, and the usage list shows the stop.
☐ Put it online and add the key there
Follow the hosting guide to publish the project.
In Vercel open Settings, then Environment Variables, and add AI_API_KEY there.
You should see: A live link where the agent answers.
☐ Ask for a security check
Press Copy and send it in the same chat.
You should see: A list of problems, each with the file and the fix, or a clear all-clear.