How do you build an AI agent for a business? Pick one task with a result you can actually check, then decide what the agent must NOT be allowed to do. The model choice can wait
Picture an incoming enquiry: someone writes in their own words, the agent asks for missing details and prepares a record for a team member. Useful already. Now let it quote a price, change the CRM status and make a promise to the customer. Same agent. Very different cost of getting it wrong
Define the job before calling it an agent
Write down what comes in and what should come out. Not "helps with sales", but "extracts a request from an email, looks up the relevant information and drafts a reply". Drafting is an outcome. Sending it is a separate permission
If the steps never change, a simple workflow may be enough. Anthropic distinguishes predefined workflows from agents that choose their own tools. Complexity alone does nothing for the business
Give it only the access the task needs
Email: read the relevant folder. Calendar: check open slots. Knowledge base: look up the current instructions. CRM: prepare a record, but don't change an important status without approval. No need to hand over every key to the business just to process one enquiry))
Keep passwords, payment details and private conversations out of customer replies and activity logs. Write down when the system must stop: no reliable source means ask a person; an unverified price means don't promise it; a failed tool call means report a failure, not "done"
Check the work, not the confident wording
Before sending anything externally, test a routine enquiry, an incomplete one, a repeat request and conflicting information. Did the agent use the right source, avoid filling in missing facts and stop before an action it isn't authorised to take? A polished reply with the wrong record is still an error, just better dressed
If you need a system fitted to your workflow, see custom AI agent development and a personal AI assistant example. But the first real step is still the same: define a testable task and the point where a person takes over