To build an AI agent that does real work, pick one repetitive task, write a clear brief, give the agent the context and tools it needs, check its output against real examples, then improve it a little every week. You do not need to code. You need a task worth handing over and the patience to test it properly.
This guide walks through the six steps we teach on the Node House agentic AI training, with the mistakes that trip most people up.
What an AI agent is, and what it is not
A chatbot answers a question and waits for the next one. An agent is given a goal, works through the steps to reach it, uses tools along the way (your email, a spreadsheet, a website), checks what it has done and hands back something finished.
That does not mean it runs unsupervised. The useful agents at work are closer to a capable new starter: clear instructions, the right access, and a person who reviews the output until it has earned trust.
Step 1: pick the right first task
Your first agent should be boring. Look for a task that:
- happens at least weekly
- follows roughly the same steps each time
- involves gathering, copying, summarising or checking information
- has an output you can judge quickly (a report, a draft, a list)
- would not cause harm if the first version is wrong, because a person checks it
Weekly reports, meeting follow-ups, research summaries and inbox sorting are good starting points. Anything that moves money or speaks directly to customers can come later.
Step 2: write the brief
Most agents fail because the brief is vague. Write it as if you were handing the task to a colleague on their first day:
- Goal: what finished looks like, in one sentence.
- Inputs: where the information comes from.
- Steps: the order you would do it in.
- Output: the format, length and where it goes.
- Rules: what it must never do, and when to stop and ask.
- Examples: two or three good past outputs.
Step 3: give it context
An agent only knows what you give it. Add the documents, templates, tone of voice and past examples it needs to produce work that fits how your business does things. This is the step that turns generic answers into useful ones.
Step 4: connect the tools, carefully
Connections are what make an agent useful: reading a shared drive, pulling figures from a spreadsheet, drafting an email. Start with read-only access and drafts, not sending or editing. Widen access only once the output is consistently right.
Step 5: check the work
Before you rely on it, run the agent on ten real past examples where you already know the right answer. Note where it goes wrong, fix the brief or the context, and run them again. Keep those examples: they become your test every time you change something.
Step 6: put it to work and improve it
Use it for real, with a person reviewing every output at first. Each week, look at what you had to correct and update the brief. Track the time it saves, so you know whether to build the next one.
Common mistakes
- Starting with a task that is too big or too rare to test.
- Writing a one-line brief and blaming the AI for vague results.
- Giving full access on day one.
- Skipping the test set, so nobody knows whether a change made it better or worse.
- Building alone, so the team never adopts it.
A real example: our company brain at Summon
At Summon we built what we call our company brain. It takes in all our contacts and talks to Notion, where our work lives. From there, agents build our task lists, keep our status sheets up to date, feed our testing plans, write the notes we read before client calls and help fill in timesheets.
You do not need to build all of that at once. Start with one job: a single agent with a clear brief, a few real examples to test against and a person checking the output. Once it works, the next agent can use the same data, and that is how a company brain grows.
Where to go next
If you want to build your first agent with help, join a Node House cohort in London, or take the online course at your own pace, built around a task from your own job. If you would rather have it built for you, see AI workflow automation for business.