AI Agent Index
+ SubmitCompareAlternativesDefinitionsAPI
Home/Guides/What is an AI Agent?

Guide · Fundamentals

What is an AI Agent?

An AI agent is software that autonomously takes actions to complete a goal without requiring human input at each step. Understanding what AI agents are, how they work, and where they fit is the foundation for evaluating any specific tool.

One sentence definition: An AI agent is software that perceives its environment, makes decisions, and takes actions autonomously to achieve a defined goal.

The Simple Definition

Traditional software does what you tell it to do, one command at a time. An AI agent does what you ask it to achieve and figures out the steps itself.

Give a traditional tool the task of finding 200 companies and sending personalised emails and it waits for you to do each step manually. Give the same task to an AI sales agent and it identifies the companies, researches each one, writes personalised emails, sends them, tracks responses, follows up, and logs everything in your CRM — without you touching the keyboard.

How AI Agents Work

LLM reasoning engineA large language model (GPT-4, Claude, Gemini) that understands goals, plans steps, and generates outputs.
Tools and integrationsAPIs, databases, browsers, and applications the agent can use to take real-world actions.
MemoryShort-term context within a task and long-term memory across sessions so the agent improves over time.
Feedback loopThe ability to evaluate its own outputs, correct mistakes, and retry failed actions without human intervention.

AI Agent vs Chatbot vs Automation

ChatbotAutomationAI Agent
Driven byUser messagesPredefined triggersGoals and reasoning
Decision makingResponds to inputFollows fixed rulesPlans and adapts
Multi-step tasksNoLimitedYes
Handles exceptionsNoNoYes
Improves over timeNoNoOften yes

Types of AI Agents

AI Sales Agents

Autonomously prospect accounts, write personalised outreach, manage follow-up sequences, and sync results to your CRM.

Examples: Instantly.ai, Apollo.io, Artisan Ava, Clay

AI Customer Support Agents

Resolve support tickets, triage queries, handle returns and refunds, and escalate complex issues to human agents.

Examples: Intercom Fin, Zendesk AI, Sierra, Decagon

AI Research Agents

Conduct multi-step web research, search academic literature, synthesise findings, and produce structured reports with citations.

Examples: Perplexity AI, Elicit, ChatGPT Deep Research, Consensus

AI Marketing Agents

Generate content, optimise SEO, automate paid campaigns, personalise messaging, and report on performance.

Examples: Jasper, Copy.ai, Persado, Albert.ai

AI Coding Agents

Write, review, and refactor code across entire codebases — from inline autocomplete to fully autonomous software engineering.

Examples: Cursor, GitHub Copilot, Devin, Windsurf

Frequently Asked Questions

What is an AI agent?

An AI agent is software that autonomously takes actions to complete a goal without requiring human input at each step. Unlike traditional software that responds to commands, AI agents plan, decide, and act on their own.

What is the difference between an AI agent and a chatbot?

A chatbot responds to individual messages. An AI agent takes multi-step autonomous action toward a goal without a human directing each step.

What are examples of AI agents?

AI sales agents that prospect and send outreach, AI coding agents that write and review code, AI customer support agents that resolve tickets, and AI research agents that conduct multi-step research.

How do AI agents work?

AI agents use a large language model as a reasoning engine, connect to external tools to take action, and maintain memory across steps to complete goals autonomously.

Browse AI Sales Agents

200+ agents indexed →

Compare Agents

Side-by-side comparisons →

How to Evaluate an Agent

Buying framework →

Sources & References

  1. 1.
  2. 2.
  3. 3.
    The State of AI in 2024 — McKinsey, 2024
  4. 4.