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What Is a Large Language Model?

If you've used ChatGPT or Copilot, you've used a large language model. Here's what an LLM actually is, how it writes answers one piece at a time, what it's good at, where it goes wrong, and how it connects to AI agents at work.

5 min read
Two felt puppets sit together at a small table with a laptop as a stream of colorful blank felt tiles floats above it, as if building a sentence piece by piece.

If you've used ChatGPT, Gemini, Claude or Copilot, you've used a large language model. You may have also heard the short name for it: an LLM. It's the engine inside almost every AI tool people talk about at work today.

You don't need a computer science degree to understand what it is. Here's the short version, with everyday examples.

The one-sentence answer

A large language model is a computer program that has read a huge amount of text and learned to predict what words should come next.

That's really it. When you type a question, the model writes its answer one small piece at a time, each time picking the piece that best fits everything that came before.

A simple way to picture it

Think about the autocomplete on your phone. You type "Running a few minutes" and it suggests "late." It learned that from seeing many messages like yours.

An LLM works on the same basic idea, but at a much larger scale. Instead of guessing one word from your last few words, it looks at your whole question, plus everything it learned from reading books, websites and other writing, and builds a full answer.

Google's own introduction to large language models describes a language model as something that "estimates the probability" of a piece of text appearing in a longer sequence. In everyday words: it's very good at guessing what comes next.

What are "tokens"?

You'll sometimes hear people talk about tokens. A token is just a small chunk of text. It might be a whole word, part of a word, or a punctuation mark.

Google's guide gives a nice example: the word "unwatched" might be split into three tokens: "un," "watch," and "ed." For English, Google says one token is about four characters, or about three-quarters of a word. So 400 tokens is roughly 300 words.

Why does this matter to you? Many AI tools measure how much you can send them, and how much they cost, in tokens.

Why is it called "large"?

Two reasons. First, these models learn from an enormous amount of text. Second, the models themselves are huge. They contain billions of tiny settings that get adjusted during training until the model gets good at predicting text.

You can think of training like a student reading a whole library and taking notes. The model doesn't keep a copy of every book. It keeps patterns: how sentences are built, how ideas connect, what a polite email sounds like, what a contract usually includes.

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What LLMs are good at

Because they're so good with language, LLMs are useful for a lot of everyday office work:

  • Writing first drafts. Emails, job posts, meeting summaries, product descriptions.
  • Summarizing. Turning a long report or email thread into a few clear points.
  • Rewording. Making something shorter, friendlier, more formal, or easier to read.
  • Answering questions. Explaining a topic or finding the key fact in a document you give it.
  • Translating. Moving text between languages.

You're not alone if you've started using them. A Pew Research Center survey of 5,119 U.S. adults in February 2026 found that about half (49%) now use AI chatbots like ChatGPT, Gemini or Copilot, up from about a third in 2024. Pew found search and work are the most common reasons people use them.

What LLMs get wrong

LLMs are impressive, but they have real limits worth knowing:

  • They can make things up. Because an LLM is built to produce likely-sounding text, it can write something that sounds right but isn't. People call this a "hallucination." Always check facts, numbers and names.
  • They may not know recent news. A model only knows what it learned during training, unless it's connected to a live source like a web search.
  • They don't know your business. Out of the box, an LLM has never seen your price list, your customer records or your company policies.
  • They don't take action on their own. A plain LLM writes text. It doesn't send the email or update the spreadsheet.

That last point is a good way to understand the next step in AI at work.

From LLMs to AI agents

An AI agent is an LLM that has been given tools and a job. Instead of just writing a reply, it can look things up in your systems, follow steps, and take actions, like filing a ticket, updating a record, or sending a report every morning.

If the LLM is the brain that's good with words, the agent is that brain with a desk, a login and a to-do list.

The bottom line

A large language model is a text-predicting engine trained on a massive amount of writing. It's great at drafting, summarizing and explaining, and it needs a human to check its facts. It becomes far more useful when it's connected to your real work.

That's the idea behind Workmate. We build custom AI agents on top of the best language models for each task, connect them to the apps your team already uses, and set clear permissions so they can help with real work, safely. You don't have to pick a model or understand tokens. You just get a teammate that knows how your business runs.

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