What is an AI agent?

Unlike a chatbot that only answers, an agent takes a goal and keeps going, using tools and checking results, until the job is done. How it works, what it suits, and what to settle before you hand it work.

Key ideas

1. 1

   From answering to doing

   A chatbot answers as much as you ask. Give an agent a goal, such as "find out why refunds went up last month," and it decides for itself what to do first, then looks things up and runs the numbers until the job is done.

   Between the two sits the workflow: it uses an LLM, but a developer fixes the order of steps in advance, such as classify, draft, then human review. With an agent, the LLM decides even that order as it goes.

   Chatbot, workflow and agent compared

   Approach	Who decides the next step	Example
   Chatbot	A person, one question at a time	Paste in meeting notes and get a summary
   Workflow	A developer, in a fixed order	A message arrives → classify → draft a reply → staff review
   Agent	The LLM, step by step as results come in	To find why refunds rose, it queries data, calculates, then queries again

2. 2

   It loops: decide, use a tool, check

   Inside, an agent is usually simple. The LLM looks at the goal and picks a tool and its inputs; the app or service runs the tool and returns the result. The LLM reads the result, decides the next step, and repeats until the goal is met.

   Tools are capabilities wired in ahead of time: search, database queries, reading files, calculations, drafting an email. Because it sees a real result at every step, it can change course midway when the first plan turns out wrong.

   An agent working on "Tell me whether refund requests rose this month compared with last month" (example)

   Step	The LLM decides	Tool used	Result
   1	Start with this month's messages	Query the support database (October)	412 messages
   2	Count only the refund requests	Tally by category	57 refund requests
   3	Last month's figure is needed to compare	Query the support database (September refunds)	41 refund requests
   4	Ready to answer	(no tool)	"57, up 16 from 41 last month"

   Check it

   • When you use an agent-based service, check that it shows a step-by-step log of which tool it used with which inputs. Without one, you can't tell at which step a wrong result crept in.
3. 3

   Good fits, and jobs it isn't ready for

   Agents suit work where you can't predict how many steps it will take or fix the order in advance. In exchange, every extra step adds time and cost, and a small mistake early on can carry through to the end.

   So start with the simplest approach that works. If one request does the job, use a chatbot; if the steps are always the same, a workflow is enough.

   Matching the approach to the job

   Kind of job	Best fit	Why
   Answering one question, summarizing, translating	Chatbot (one request)	One step, so no agent needed
   Repetitive work that always runs in the same order	Workflow	A fixed order is cheaper and more predictable
   Research or fixes where the number of steps is unknown	Agent	The next step depends on each result
   Hard-to-undo actions (payments, mass deletion)	A person does it, or a person must approve	A small misjudgment would be carried out as is

   I want to pick which of my team's tasks suit an agent. For each of the three below, tell me in a table whether it fits 'one request', 'a fixed workflow' or 'an agent', and why.
   1) Building the weekly sales report every Monday, always in the same format
   2) Finding out why customer complaints suddenly went up
   3) Translating a one-page contract from English

   Here's how the three break down.

   The best fit for each task (example)

   Task	Best fit	Why
   Weekly sales report	Fixed workflow	The same data is gathered in the same order into the same format each week, so the steps can be set in advance
   Why complaints went up	Agent	There's no telling in advance which data to check, or how many times
   Contract translation	One request	It's a single step, but check your company's security rules before pasting in a contract

4. 4

   Settle these first: permissions, approval, stopping

   Because an agent carries out several steps on its own, the damage from a mistake, or from being tricked, can grow just as much. Run it thoroughly in a test environment first, and connect it to real work only after settling the four points below.

   Agents that read web pages, emails or documents can be fooled by instructions hidden inside them. This is called prompt injection, and attackers use it to steal data or trigger unwanted actions.

   A checklist before you connect an agent

   Settle	Why	Example
   Minimum permissions	Limits how far a mistake or an attack can reach	Allow reading only at first; block writing and deleting
   Human approval for hard-to-undo actions	Stops a small misjudgment from being carried out	A person confirms before any email is sent, payment made or file deleted
   Stopping conditions	Keeps it from looping on and running up costs	A maximum number of steps, a spending cap
   Treat what it reads as data only	So hidden instructions in web pages or emails can't steer it	Don't let it follow instructions found in outside content; review its log

   Check it

   • Start with a test account and fake data, and check the step-by-step log for what the agent did and why.
   • Test that the approval step really works, and that the agent actually stops when you don't approve.