What Do These AI Buzzwords Actually Mean

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Agents, Skills, RAG… What Do These AI Buzzwords Actually Mean?

πŸš€ A Friendly Walk Through the Chaos of Modern AI Terminology

How many of these words do you really understand?

LLM. Prompt. Context. Memory. Agent. RAG. MCP. Skill. Workflow.

If your honest answer is "uh… some of them?" β€” congratulations, you're exactly where you need to be.

Today, let's unpack all these intimidating buzzwords in plain English. No hype. No marketing fluff. Just a calm walk through what's really going on under the hood.

And by the end, you'll see something surprising:

  • Most "intelligent agents" are just the parts of the system that don't require intelligence at all.

Let's begin.



🧠 It All Starts With the LLM

Everything begins with the Large Language Model β€” or LLM.

At its core, an LLM just predicts the next word. That's it. It's basically very advanced autocomplete.

Early language models were… not great. But as parameters increased, something interesting happened β€” intelligence emerged. So we added the word "large" to distinguish them from the smaller, weaker versions.

And boom. New term unlocked: LLM.

But remember: Underneath all the magic, it's still just predicting the next token.



πŸ’¬ From Word Prediction to Conversation

On its own, an LLM just continues text.

But if we structure it as:

  • One role asking
  • One role answering

Suddenly, it feels intelligent. Let's imagine you're the boss. The LLM is your employee β€” let's call him Little L.

There's one catch:

  • Little L can only answer one question at a time. No follow-ups.

That limitation becomes important later.



✍️ Prompt, Context, and Memory (AKA Fancy Names for Text)

You give Little L instructions. You decide to call each interaction a prompt.

Then you realize your prompt has two parts:

  • Background information β†’ context
  • Final instruction β†’ the actual task

Then you want follow-up questions β€” but Little L can't do follow-ups.

So you hack it.

Before each new question, you paste the previous conversation into the context. Now it looks like memory.

You call that Memory.

And just like that, you've invented four buzzwords.

But in reality?

It's still just stuffing more text into the prompt.



πŸ” When LLMs Can't Search the Internet

Eventually, you notice a problem:

  • The model doesn't know recent information.
  • It sometimes makes things up.
  • It can't search.

So you think: "Let's give it internet access."

But the model itself can’t browse. It only outputs text.

So you build a small program that:

  1. Lets the model say, "I need to search."
  2. Runs the search.
  3. Feeds results back into the model.

Now you’ve created something new.

You call it an Agent.



πŸ€– What Is an Agent, Really?

Here's the honest truth:

  • An agent is just a program that handles everything the model shouldn't.

It's glue code.

It:

  • Receives model output
  • Decides whether to call tools
  • Runs tools
  • Sends results back to the model

It's not magic. It's orchestration.

Some early "agents" were literally just extra prompts with fancy branding.



πŸ“š Enter RAG: Retrieval-Augmented Generation

Next problem: searching structured knowledge.

Instead of keyword search, we use vector similarity.

You embed documents into vectors. You retrieve semantically similar chunks. You inject them into the prompt.

This pattern is called:

RAG (Retrieval-Augmented Generation)

Again β€” what's really happening?

You're stuffing relevant text into the context before generation.

Same principle. New name.



πŸ”§ Function Calling vs MCP (And Why People Confuse Them)

Two terms that often get mixed up:

Function Calling

An agreement between the agent and the model.

The model replies in structured format (like JSON) so the agent can parse tool calls.

It's like defining an API contract between frontend and backend.

MCP (Model Context Protocol)

A separate agreement between:

  • The agent
  • External tool services

It defines:

  • How tools are listed
  • How they're called
  • How parameters are passed

These two are completely different layers.

One is model ↔ agent formatting.

The other is agent ↔ tool communication.

They do not replace each other.



πŸ—οΈ Workflow, LangChain, Skill β€” What's the Difference?

Now we move from rigid to flexible systems.

Hard-coded programming

Stable, predictable, but rigid.

Workflow (drag-and-drop logic)

Same idea, just visual for non-programmer.

Skill

Prewritten instructions + scripts the agent can dynamically choose.

Skill is more flexible β€” but less predictable.

And yes, a lot of it is just:

  • A folder
  • A skill.md file
  • Some scripts

Is just old wine in a new bottle.



🧩 Subagents: Solving Context Explosion

As tasks grow complex, context grows huge.

Solution?

Subagents.

They:

  • Handle subtasks independently
  • Isolate context
  • Return results

That's it.

It's context isolation with branding.



🧡 The Big Picture: What's Actually Happening?

Here's the unifying idea that explains everything:

  • All these systems exist to automatically add context to prompts or reduce how often humans interact with the model.

That's it.

  • Search β†’ adds context
  • RAG β†’ adds context
  • Skill β†’ adds structured context
  • Agents β†’ automate context assembly and tool use

Everything revolves around prompt + context.



🎯 What Agents Actually Do

Remember the line from earlier?

  • Agents are made of all the parts that don’t require intelligence.

In any workflow:

  • Fuzzy semantic decisions β†’ handled by the LLM
  • Deterministic logic (like extracting PDF text) β†’ handled by code

Agents sit in between.

They route tasks.

They don't think β€” they delegate.



🧠 The Universal Method to Understand Any Future AI Buzzword

Here's the mental shortcut:

When you see a new AI concept, ask:

  1. Is it adding context to the prompt?
  2. Is it automating tool usage?
  3. Is it structuring model output?
  4. Is it isolating context?

If yes β€” it's just another variation of the same core pattern.

And now you can decode it instantly.



β˜• Final Thoughts

AI today is full of hype cycles.

Every few months, a new term explodes across Twitter, Medium, and YouTube.

But underneath?

It's still:

  • Prompts
  • Context
  • Tools
  • Orchestration

Once you see that structure, the confusion disappears.

And instead of feeling overwhelmed by buzzwords…

You start smiling at them.

Because now?

You know what they really are.

Made by Alvin Au Β© 2026