Skip to content

AI, decoded

What makes an AI agent different from an LLM?

An LLM answers; an agent does. The difference is the system built around the model, which in production means four things: multiple models orchestrated together, memory and context, tools it can call, and a layer of checks running the whole time. The model is just one part of the system. Fireworks AI's Aishwarya Srinivasan told Chain of Thought that Notion's head of AI engineering described fine-tuning models on Fireworks for latency-sensitive parts of Notion AI, which uses multiple models.

· Updated · Chain of Thought

Level 1: How AI works · 1.5 From chatbot to agent

AI AgentsAI Engineering

  • 4 episodes
  • 5 guest clips
  • 8 glossary terms
A large number 4 beside a model block with four modules plugged in around it, with the words: 4 things turn a model into an agent.

In detail

Agent or workflow?

Not every system with an LLM and tools is an agent in the strict sense. Anthropic’s Building effective agents draws the line by who decides the next step. In a workflow, models and tools follow paths written in code. In an agent, the model directs its own process and tool use and controls how it gets the task done. Both count as agentic systems. The same post recommends workflows for well-defined tasks, because they are more predictable and consistent, and agents where the task needs flexibility and model-driven decisions. The four parts below apply to both; what changes is how much of the routing you hand to the model. Agentic workflow and agentic vs. non-agentic AI cover the distinction.

1. Orchestration, not one model

A demo often uses a single model. A production agent system often runs a combination: small ones, large ones, some fine-tuned, some open, some proprietary, each picked for what it is good at. The job stops being “prompt the model” and becomes “coordinate the system.”

2. Memory and context

The agent needs access to your data, the memory it builds up, and the right information at the right moment. Without it, you have a clever autocomplete. With it, you have something that can work on your problem. Agent memory covers what an agent keeps between steps and sessions.

3. Tools it can call

This is where it crosses from talking to doing. The agent reaches real tools and APIs, takes actions, and operates software instead of just describing what to do. Mechanically, that is tool use: the model emits a structured call and your code runs it.

4. Evals and guardrails

The part that gets skipped. Aishwarya Srinivasan’s rule is to quantify every step, so when something breaks you can see where and why. Add the guardrails and the human-in-the-loop checkpoints, and you have a system you can trust in production instead of one you cross your fingers on.

Update, October 3, 2026: In episode 75, Kapil Chhabra describes WisdomAI’s analytics workflow: decomposing a question, generating and executing queries across data sources, verifying the returned information, repairing errors and recomposing the response. The verification and repair steps provide a concrete example of checks around the model’s output. Episode 75 was sponsored by WisdomAI (sponsor thanks at 4:13).

Why it matters

When someone says “we built an agent,” ask what system they built around the model. The model is the easy part now. The orchestration, the memory, the tools, and the checks are where it works or falls apart.

What makes an AI agent: the model plus four things built around it Left, an LLM on its own: a prompt goes in, the model answers with text. Right, an agent: the model sits at the center of a system with four things built around it. One, orchestration: small, large, fine-tuned, open and proprietary models coordinated together. Two, memory and context: your data, the memory it builds up, the right information at the right moment. Three, tools: real tools and APIs it can call, so it moves from talking to doing. Four, evals and guardrails: every step quantified, with human-in-the-loop checkpoints. Aishwarya Srinivasan, episode 42: it is not a model that you are surfacing to your user, it is a system. An LLM answers. An agent does. The model is one part. In production, four things built around it make a system that can act. AN LLM ON ITS OWN a prompt the model an answer, in text It answers. AN AGENT: THE MODEL INSIDE A SYSTEM the model 1 · ORCHESTRATION small, large, fine-tuned, open, proprietary 2 · MEMORY your data, memory, the right info at the right moment 3 · TOOLS real tools and APIs: from talking to doing 4 · EVALS AND GUARDRAILS quantify every step; human checkpoints It does. “It is not a model that you are surfacing to your user. … It is a system that you’re surfacing to your user.” Aishwarya Srinivasan, episode 42. The system around the model is where it works or falls apart.
An LLM answers; an agent does, because of the system built around the model. The quote and the multi-model framing are Aishwarya Srinivasan’s, from episode 42. Download the image

Hear it from the guest

“It is not a model that you are surfacing to your user. It is a software. It is a system that you're surfacing to your user”
Aishwarya Srinivasan, Fireworks AI EP 42 · around 47:39 · read the transcript
“You're going to have different combination of smaller models, mid sized model, larger models. Some of them are going to be fine tuned. Some of them are going to be distilled. Some of them are going to be proprietary. Some of them are going to be open source.”
Aishwarya Srinivasan, Fireworks AI EP 42 · around 8:20 · read the transcript
“If there is an error, it needs to self-rectify that error.”
Watch on YouTube
“You're seeing a lot of definitions flying around by … all sorts of founders around, like, this is my definition. This is my definition. But at the end of the day, it's basically task completion.”
“The whole point of agents is that it does stuff rather than just … spew out tokens.”

Quotes lightly edited to remove filler words.

From the conversation

This explainer is drawn from these episodes — each carries its full transcript.

Concepts in this explainer

Agentic WorkflowLarge Language ModelAgentic AIAI AgentAgent LoopAI AssistantChatbotCoding Agent