What Are AI Agents and How Do They Work?
May 22, 2025

Kevin Bartley
Customer Success at Stack AI
Artificial Intelligence (AI) has undergone a rapid evolution in the last decade, leading to the rise of intelligent software entities capable of performing tasks once exclusive to human cognition. At the forefront of this evolution is the emergence of AI agents—autonomous systems that can perceive their environment, reason over data, and act to achieve specific goals. This article explores the question "What Are AI Agents and How Do They Work?" in an academic yet practical framework, with implications for enterprise applications, research, and society at large.
Understanding the Definition of AI Agents
To grasp what AI agents are and how they work, it is imperative to begin with a rigorous definition. An AI agent is a software system that perceives its environment through sensors and acts upon that environment through actuators based on a built-in policy or learned model.
From a computational standpoint, an AI agent is defined by the tuple:
Agent = ⟨E, P, A, π⟩
Where:
E represents the environment
P is the percept space (input data)
A is the action space (output decisions)
π is the policy or function mapping percepts to actions
This formalization aligns with both symbolic AI paradigms and modern deep learning-based agents. Whether deployed in robotics, digital customer service, or autonomous vehicles, the defining hallmark of an AI agent is autonomy and adaptability.
Historical Context and Evolution of AI Agents
The concept of AI agents can be traced back to the early stages of cybernetics and control theory in the mid-20th century. Early implementations such as Shakey the Robot (1966) by SRI International were primitive agents that could navigate and make decisions based on sensor input.
With the advent of machine learning and the exponential growth of computational resources, AI agents have transcended static rule-based models. Today, modern AI agents are driven by reinforcement learning, deep neural networks, and probabilistic planning algorithms, making them capable of learning optimal behavior through experience.
Types of AI Agents
A comprehensive academic discussion of what are AI agents and how do they work necessitates an understanding of the various types of agents and their corresponding architectures:
1. Simple Reflex Agents
These agents act solely based on the current percept, using condition-action rules. They are stateless and efficient but lack adaptability.
2. Model-Based Reflex Agents
These maintain an internal state to track parts of the environment not currently visible. They are more robust than simple reflex agents.
3. Goal-Based Agents
These agents incorporate goal information into their decision-making process, often utilizing search and planning algorithms.
4. Utility-Based Agents
They aim to maximize a utility function, allowing for trade-offs between conflicting goals.
5. Learning Agents
These agents improve their performance over time based on feedback from their environment. Techniques such as reinforcement learning are central to their architecture.
How AI Agents Work: The Process Pipeline
Understanding how AI agents work involves dissecting the computational pipeline that governs their functioning:
1. Perception
The agent uses sensors or APIs to perceive the environment. For instance, a chatbot AI agent perceives input text, while a self-driving car agent perceives images and LiDAR data.
2. Reasoning and Decision-Making
This is the core of the AI agent. Based on the perception, the agent applies a reasoning model—typically a decision tree, neural network, or probabilistic planner—to evaluate possible actions.
3. Learning
Modern agents incorporate learning modules to refine their reasoning. Deep Reinforcement Learning (DRL) is a dominant approach where agents learn optimal policies through reward-based feedback.
4. Action
Finally, the agent acts upon the environment. In digital systems, this might mean sending a message, changing a database entry, or triggering another process.
Applications of AI Agents in the Real World
The relevance of understanding what AI agents are and how they work becomes clear when we consider their applications:
Customer Service: AI agents power intelligent chatbots that can resolve queries in natural language.
Healthcare: Diagnostic AI agents analyze imaging and patient history to suggest treatment plans.
Finance: Trading agents make real-time decisions based on market data streams.
Autonomous Vehicles: These complex agents process multi-modal data to navigate and avoid collisions.
Stack AI, a leading enterprise AI platform, offers robust solutions for deploying intelligent agents across industries. Their integrated environment allows businesses to deploy, monitor, and optimize AI agents in mission-critical applications.
Challenges in AI Agent Development
While the capabilities of AI agents are formidable, their development is fraught with challenges:
Explainability: As agents rely more on deep learning, their decision-making becomes less transparent.
Ethical Decision-Making: Agents in domains like healthcare and defense face ethical dilemmas that are difficult to encode algorithmically.
Generalization: AI agents often perform well in trained environments but struggle in novel or adversarial settings.
Resource Efficiency: Real-time decision-making requires computational efficiency, particularly in embedded systems or edge computing scenarios.
Interoperability with Human Systems
A profound insight in understanding what AI agents are and how they work is recognizing their role as collaborators rather than replacements for humans. Human-in-the-loop systems ensure that agents complement rather than override human judgment. The design of such systems must focus on trust, interpretability, and transparency.
The article what is an ai agent offers a detailed breakdown of how these agents are designed with human-centric workflows in mind, particularly in enterprise settings.
Future Directions of AI Agents
The trajectory of AI agents is converging towards general-purpose agents—systems capable of executing a wide range of tasks with minimal retraining. Projects like OpenAI’s GPT-based agents or DeepMind’s AlphaAgent prototypes are stepping stones toward Artificial General Intelligence (AGI).
Meanwhile, practical developments focus on multi-agent systems where teams of AI agents collaborate or compete, such as in logistics networks, air traffic control, or even multiplayer games.
Companies looking to operationalize AI agents in business settings should explore Stack AI’s dedicated ai agent solutions, which offer powerful no-code tools to build and deploy multi-modal intelligent agents rapidly.
Conclusion
The question "What Are AI Agents and How Do They Work?" opens the door to a foundational area of artificial intelligence that intersects computer science, cognitive psychology, and systems engineering. AI agents represent a major leap in automation and intelligence, enabling machines to operate with purpose, adaptability, and autonomy.
From simple rule-based agents to sophisticated self-learning systems, AI agents are transforming how we interact with software, machines, and data. As they become more prevalent in business and society, it is vital to understand both their inner workings and broader implications.
For enterprises looking to harness the power of autonomous systems, platforms like Stack AI provide the tools and infrastructure to build, train, and deploy intelligent AI agents efficiently and at scale.
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