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What Is an Agent — One article to bring you understanding

What is an Agent? An Agent is an AI that takes action on its own — you give it a goal, and it breaks the task down, calls tools, and gets the job done.

The fundamental difference between an Agent and a Chatbot: a Chatbot is a passive "advisor" — you ask it how to cancel a flight, and it gives you the steps; an Agent is an active "doer" — you tell it to cancel the flight, and it does it for you, directly.


So, What Exactly Is an Agent?

Lilian Weng of OpenAI summed up the core of an Agent in one sentence — Agent = LLM + Planning + Memory + Tools. NVIDIA describes it as "an advanced AI system capable of reasoning, planning, and executing multi-step tasks." Anthropic's 2025 official research paper defines it as "a system in which the LLM dynamically takes the lead on its own workflow and tool calls."

All of these definitions are really saying the same thing: the core of an Agent isn't conversation — it's action.

An Agent runs on four capabilities:

Reasoning — the Agent's brain. Given a task like "analyze our company's Q1 sales data, find the fastest-growing product, and email a report to the team," the Agent breaks it down into steps on its own: connect to the database to pull Q1 data → calculate the growth rate of each product → generate a visualization → write the report email → send it to the team. Every step is reasoned in real time, not following a predefined path.

Memory — the Agent's notebook. It comes in two types: short-term memory holds the context of the current conversation, while long-term memory uses a vector database to store historical experience, user preferences, and industry knowledge. Without memory, an Agent can't handle complex multi-session tasks — it's like a person with amnesia who can't complete work that spans multiple conversations.

Tools — the Agent's hands and feet. Common tools include: search engines (for real-time information), code interpreters (running Python for math and data analysis), API interfaces (sending emails, looking up orders, calling ERP/CRM systems), databases (SQL queries and writes), and file systems (reading/writing documents, generating reports). Which tool to call, what parameters to use, and how to use the result — all of this is decided by the Agent itself based on the current task, not hard-coded.

Action — the Agent's output. An LLM can only output text, but an Agent can actually change the external environment — send an email, update a database record, submit a code PR, cancel a flight order. Traditional AI: you ask it "how do I cancel my flight," and it replies with the steps. Agent: you say "cancel my flight," and it does it for you, directly.

Gartner forecasts that by 2028, 33% of enterprise software will have Agentic AI built in, and 15% of daily work decisions will be made autonomously by Agents. 2026 is also being called "Year One of Enterprise Agents in the workforce" by the industry.

Quick reference — the four core components:

Component Role Implementation
Reasoning Break down tasks, plan steps Real-time LLM reasoning
Memory Store context and historical experience Short-term context + long-term vector store
Tools Call external capabilities API / database / code interpreter
Action Change the external environment Email / database / UI operations

How to Build an Agent from Scratch?

Three steps: pick a platform → define the Agent → run and iterate.

Platform choice depends on your route. Developers go the code routeLangChain / LangGraph (the most mature ecosystem), CrewAI / AutoGen (multi-Agent collaboration). Non-developers go the low-code route — visual orchestration platforms like SoloEngine.

Define the Agent around four things — Role (e.g., "You are a cross-border e-commerce customer service Agent"), Goal ("Handle customer order inquiries, refund requests, and logistics questions"), Tools (connect to the order lookup API, refund interface, logistics tracking API, and FAQ knowledge base), and Constraints ("Don't handle price negotiations; refund amounts must not exceed the order amount; flag any fraud risk for human review").

Once running, the Agent loops autonomously: receive a task → reason and decide → call tools → produce output → observe feedback → improve the next round.

For example, a user says, "Prepare next week's stock analysis report for me." The Agent's autonomous execution looks like this: fetch the latest stock prices and K-line data → pull the latest earnings reports and guidance → search industry news and analyst views → analyze the data and build visualizations → write a structured report and save it to the cloud. The whole flow takes just 2 minutes, while a Chatbot would just reply, "You should pay attention to the following..."


The Fundamental Difference Between Agents and Traditional Automation

In one line: Agents make their own decisions. Traditional automation follows preset rules.

Dimension Agent (Intelligent Agent) Traditional Automation (RPA/Chatbot)
Core logic Goal-driven (given a goal, plans its own path) Rule-driven (if-then preset rules)
Task type Open-ended, multi-step complex tasks Fixed-flow, repetitive tasks
Decision-making LLM reasons in real time, dynamic judgment Preset conditional branches, mechanical execution
When something unexpected happens Reflect + retry + adjust strategy Stuck, waits for human to restart
Tool calls Picks tools and call methods on its own Preset fixed call chain

Take the flight-cancellation scenario for comparison. A user says, "Cancel my 8 AM flight to Beijing tomorrow." Traditional automation (RPA) replies, "You can cancel the order in the app" — it can only pass along information. The Agent directly operates the user's travel app — look up the flight → confirm the order → calculate the cancellation fee → execute the cancellation → send a confirmation SMS. One is a worker who follows a manual; the other is an employee who decides on their own. One gives you the path; the other walks it for you.

In one line: traditional AI is an advisor — it just talks and gives suggestions. An Agent is an employee — it takes action and gets things done.


How to Learn Agent Development?

Pick one of two routes.

The code route: Python + LangChain, for deep customization. Learn Python basics → learn API calls → learn Prompt Engineering → learn LangChain → learn LangGraph → learn CrewAI/AutoGen. Suited for developers and technical practitioners.

The low-code route: SoloEngine's visual orchestration, pick it up the same day. Drag and drop Agent components onto the SoloEngine canvas → configure roles and tools in natural language → wire up how Agents collaborate → click run. No coding required — if you can describe what you need, you're set. A lawyer can define a "Contract Review Agent" to auto-review legal clauses; an accountant can define a "Report Analysis Agent" to auto-generate financial analysis; an operator can define a "Content Operations Agent" to auto-manage a social media portfolio.

My recommendation: if you're a developer, start with the low-code platform to get quick wins and positive feedback, then move to the code route for deeper control — the two routes aren't opposites, they complement each other. If you don't code, go straight to the low-code route — SoloEngine lets non-coders define and run an AI Agent team.


Practical Advice

Most people get stuck on an "either/or" choice, but in practice the two routes are often used together: use LangChain/LangGraph for deep custom development (fine-grained control, complex chained calls), and use SoloEngine for Agent orchestration, fast validation, and GUI (a complete runtime panel). The end goal isn't picking a framework — it's building an Agent system that actually solves your business problem.

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