What Is Agentic AI?
What is agentic AI? Its definition, how an LLM calls tools in a loop, what AI agents are, and how to build one, in plain terms with a worked example.
What is agentic AI? It is software in which a large language model (LLM) decides which steps to take, calls tools to carry them out, and reads each result before choosing the next step. AI agents work this way. Instead of a fixed program, an agentic system gets a few small, reliable tools and works out the order for each request. This guide explains the agentic AI definition and AI agents explained in plain terms, with no maths.
What AI is, and where generative AI fits
AI is a broad term for software that does tasks we usually link to human intelligence. Inside it sit several layers:
- Statistical algorithms: formulas that find patterns in numbers.
- Machine learning: programs that learn patterns from examples instead of following hand-written rules.
- Deep learning: machine learning with large, many-layered neural networks.
- Generative AI: models that produce new content such as text, images or code.
What an LLM is
An LLM is a generative text model. It produces text one token at a time, predicting what comes next from everything written so far. It handles natural language because it has learned the patterns of language from very large amounts of text.
How an LLM can perform tasks
Almost any task software does can be treated as a function or an API. To call a function you write its name and the arguments you pass. In Python:
def sum(a, b):
return a + b
sum(2, 3)
That call is just text. An LLM can produce text, so if it writes calls in the exact format a program expects, software can run them. The same idea works for APIs. The model writes a structured request with a name and arguments, and the software sends it over the network. Each function or API an agent can call is called a tool. Agentic AI tools are exactly these.
What an AI agent is
An AI agent has three parts: the LLM, the tools, and the orchestrator. Orchestrator is the code that sends the user's query to the LLM and runs the tools based on the LLM's response.
The LLM tells the orchestrator which tool to call and with what arguments. The orchestrator calls it, gets the result and sends it back. If the LLM judges the task complete, it writes a plain-sentence answer. If not, it asks for another tool call.
The whole loop is the agent. Every agentic app follows this pattern at a broad level.
Why agents handle changing requirements
Classical software needs a clear specification. Take keyword research. You can write a program that takes a seed keyword, calls a keyword API, sorts the results, removes noise and returns the list. Then you want the same work starting from keywords you already rank for in Search Console, then from a draft you wrote, then from a competitor's page. Each variation needs new code, and error handling grows with each one. Traditional software covers well-defined cases, but a small change usually means a code change.
An agent works differently. You define a few small tools, each doing one job end to end:
- Extract content from a URL: returns the content of a page.
- Extract keywords from Search Console: returns the queries the site ranks for.
- Get keyword clusters from seed keywords: groups related keywords and shows their volume.
- Save keywords to the database: stores the result.
The LLM decides which tools to call, and in what order, for each new request. A new variation needs a new request, not new code.
How to build an AI agent
The build follows the same parts as above:
- Pick one task and list its steps. Keep each step small enough to be one tool.
- Write each tool to do one job end to end, such as extracting a page's content or saving results.
- Connect an LLM that reads the user's request and chooses which tool to call next, with what arguments.
- Write the orchestrator loop that runs each tool call and returns the result to the LLM until the LLM writes its final answer.
A worked example
Take this query: "Given a competitor, extract keywords from its home page, also find all keywords we rank for, and give an overview list of keyword clusters with volume."
- The LLM receives the query.
- It asks the orchestrator to extract content from the competitor's home page, and lists the keywords it finds there.
- It asks for the keywords the site ranks for in Search Console.
- With both lists in hand, it asks for keyword clusters with volume.
- It keeps only the relevant clusters and asks the save tool to store them.
- It writes a plain sentence saying the task is complete.
Four tool calls handle a task that spans two data sources and an analysis step. You can then accept the result or ask a follow-up question.
Meelu runs this kind of work on your own site. Its SEO desk uses your Search Console data and live keyword volumes, and groups keywords so each page targets one search. The agent follows the same loop, and it asks before it saves anything.
Summary
- Agentic AI, the definition in one line: an LLM working in a loop with tools.
- AI agents write tool calls as text; the orchestrator runs them and returns the results.
- Small, single-purpose tools let one agent handle requests that would otherwise need new code each time.
- Building one means defining tools, connecting an LLM and writing the loop.
- A person still decides what to keep. See how to use AI agents for marketing.
FAQ
What is agentic AI?
Agentic AI is a system in which a large language model calls tools in a loop, reads each result, and keeps going until the task is done. It is the agentic AI definition in one sentence.
What are AI agents?
An AI agent is an LLM, a set of tools, and orchestration code that runs the loop between them. AI agents explained in one line: the model decides, the tools act, and the orchestrator carries the messages between.
What are agentic AI tools?
Agentic AI tools are the functions and API calls an LLM can ask to run. A tool has a name and arguments. For example, a tool can extract content from a URL, or save keywords to a database.
How do I build an AI agent?
Define a few small tools that each do one job, connect an LLM that chooses which tool to call, and write the orchestrator loop that runs each call and returns the result. The steps are in the section on building an AI agent above.
Is agentic AI the same as generative AI?
Generative AI is the broad family of models that produce content. Agentic AI is a system built on such a model that calls tools in a loop until a task is done.
Does an agent act on its own?
It can call tools without a person at each step, but a well-built agent asks before it changes anything. Meelu works this way: it suggests, and you approve each change.
Try this workflow on your own site with Meelu. It runs the agent on your crawl and Search Console data, and asks before it changes anything.
This post is part of building Meelu, an AI assistant for digital marketing — site audits, keyword clusters, web page drafts and data analysis, with you approving every change. Download the app to run it on your own site.
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