Building AI Agents: Architecture, Tools & Implementation Guide



This content originally appeared on DEV Community and was authored by Vansh Saxena

Building AI Agents: Architecture, Tools & Implementation Guide

AI Agents are revolutionizing how we interact with software. Unlike simple chatbots, these autonomous systems can plan, execute tasks, and make decisions. Let’s dive deep into the technology.

What Are AI Agents?

AI Agents are autonomous programs that:

  • Perceive their environment through APIs and data sources
  • Reason about actions using LLMs
  • Act by calling tools and functions
  • Learn from feedback and outcomes

Core Architecture Components

1. LLM Brain (Reasoning Engine)

# Example: Using OpenAI for reasoning
from openai import OpenAI

client = OpenAI()
response = client.chat.completions.create(
    model="gpt-4",
    messages=[
        {"role": "system", "content": "You are an AI agent that can use tools"},
        {"role": "user", "content": "Book a flight to NYC"}
    ],
    tools=[flight_search_tool, booking_tool]
)

2. Memory System

  • Short-term: Conversation context
  • Long-term: Vector databases (Pinecone, Chroma, Qdrant)
  • Working memory: Current task state
# Vector memory example
from chromadb import Client

client = Client()
collection = client.create_collection("agent_memory")

# Store interaction
collection.add(
    documents=["User prefers morning flights"],
    metadatas=[{"type": "preference"}],
    ids=["pref_1"]
)

3. Tool Integration Layer

# Function calling schema
tools = [
    {
        "type": "function",
        "function": {
            "name": "search_flights",
            "description": "Search for available flights",
            "parameters": {
                "type": "object",
                "properties": {
                    "origin": {"type": "string"},
                    "destination": {"type": "string"},
                    "date": {"type": "string"}
                },
                "required": ["origin", "destination", "date"]
            }
        }
    }
]

4. Planning & Execution Engine

class AgentExecutor:
    def __init__(self, llm, tools):
        self.llm = llm
        self.tools = tools

    def execute(self, task):
        # 1. Plan
        plan = self.llm.create_plan(task)

        # 2. Execute steps
        for step in plan:
            tool = self.select_tool(step)
            result = tool.execute(step.params)

            # 3. Reflect
            if not self.validate(result):
                self.replan(step, result)

        return final_result

Popular AI Agent Frameworks

LangChain

from langchain.agents import initialize_agent, Tool
from langchain.llms import OpenAI

tools = [
    Tool(
        name="Calculator",
        func=calculator.run,
        description="Useful for math calculations"
    )
]

agent = initialize_agent(
    tools, 
    OpenAI(temperature=0),
    agent="zero-shot-react-description"
)

agent.run("What is 25 * 4 + 10?")

AutoGPT Pattern

class AutoGPTAgent:
    def run(self, goal):
        while not self.goal_achieved(goal):
            # 1. Think
            thoughts = self.llm.generate_thoughts(goal, self.memory)

            # 2. Reason
            action = self.llm.decide_action(thoughts)

            # 3. Act
            result = self.execute_action(action)

            # 4. Criticize
            self.memory.add(result)
            self.evaluate_progress(goal)

ReAct (Reasoning + Acting)

Thought: I need to find the weather in NYC
Action: search_weather(location="New York")
Observation: Temperature is 72°F, sunny
Thought: Now I should check if user needs umbrella
Action: analyze_weather(temp=72, condition="sunny")
Observation: No umbrella needed
Answer: It's 72°F and sunny in NYC. No umbrella needed!

Key Technologies & Tools

Vector Databases

  • Pinecone: Managed, scalable
  • Weaviate: Open-source, GraphQL
  • Qdrant: Rust-based, fast
  • Chroma: Lightweight, embedded

LLM Providers

  • OpenAI: GPT-4, function calling
  • Anthropic: Claude 3.5, tool use
  • Google: Gemini 2.0, multimodal
  • Open-source: Llama 3, Mistral

Orchestration

  • LangChain: Python/JS framework
  • LlamaIndex: Data-focused agents
  • Semantic Kernel: Microsoft’s framework
  • Haystack: NLP pipelines

Real-World Implementation

Example: Customer Support Agent

from langchain.agents import AgentExecutor
from langchain.tools import Tool

class SupportAgent:
    def __init__(self):
        self.tools = [
            Tool(
                name="search_knowledge_base",
                func=self.search_kb,
                description="Search company knowledge base"
            ),
            Tool(
                name="create_ticket",
                func=self.create_ticket,
                description="Create support ticket"
            ),
            Tool(
                name="check_order_status",
                func=self.check_order,
                description="Check order status by ID"
            )
        ]

    def search_kb(self, query):
        # Vector search in knowledge base
        results = vector_db.similarity_search(query, k=3)
        return results

    def create_ticket(self, issue):
        # Create ticket in system
        ticket_id = ticketing_system.create(issue)
        return f"Ticket {ticket_id} created"

Advanced Patterns

Multi-Agent Systems

class MultiAgentSystem:
    def __init__(self):
        self.researcher = ResearchAgent()
        self.writer = WriterAgent()
        self.critic = CriticAgent()

    def collaborate(self, task):
        # Research phase
        research = self.researcher.gather_info(task)

        # Writing phase
        draft = self.writer.create_content(research)

        # Review phase
        feedback = self.critic.review(draft)

        # Iterate until approved
        while not feedback.approved:
            draft = self.writer.revise(draft, feedback)
            feedback = self.critic.review(draft)

        return draft

Tool Creation Pattern

def create_tool_from_api(api_spec):
    """Dynamically create tools from OpenAPI specs"""

    @tool
    def dynamic_tool(params: dict):
        """Auto-generated tool from API"""
        response = requests.post(
            api_spec.endpoint,
            json=params,
            headers=api_spec.headers
        )
        return response.json()

    return dynamic_tool

Performance Optimization

Caching Strategy

from functools import lru_cache

@lru_cache(maxsize=1000)
def cached_llm_call(prompt, model):
    return llm.generate(prompt, model)

Parallel Tool Execution

import asyncio

async def execute_tools_parallel(tools, params):
    tasks = [tool.execute_async(param) 
             for tool, param in zip(tools, params)]
    results = await asyncio.gather(*tasks)
    return results

Challenges & Solutions

Hallucination Prevention

  • Use function calling for structured outputs
  • Implement validation layers
  • Add confidence scoring
  • Enable human-in-the-loop for critical actions

Cost Management

  • Cache frequent queries
  • Use smaller models for simple tasks
  • Implement token budgets
  • Batch similar requests

Security

  • Sandbox tool execution
  • Validate all inputs
  • Rate limiting
  • Audit logs for all actions

Future Trends

  1. Autonomous Agents: Self-improving systems
  2. Multi-modal Agents: Vision + audio + text
  3. Swarm Intelligence: Coordinated agent teams
  4. Edge Agents: Running locally on devices
  5. Specialized Agents: Domain-specific experts

Getting Started

# Install dependencies
pip install langchain openai chromadb

# Basic agent setup
from langchain.agents import create_openai_functions_agent

agent = create_openai_functions_agent(
    llm=ChatOpenAI(model="gpt-4"),
    tools=your_tools,
    prompt=your_prompt
)

executor = AgentExecutor(agent=agent, tools=your_tools)
result = executor.invoke({"input": "Your task here"})

Conclusion

AI Agents represent the next evolution in software. By combining LLMs with tools, memory, and planning capabilities, we can build systems that truly understand and act on user intent.

Key Takeaways:

  • Start with simple ReAct patterns
  • Build robust tool integrations
  • Implement proper memory systems
  • Focus on reliability and safety
  • Iterate based on real usage

Ready to build your first AI agent? Start experimenting today!

Resources:

AIAgents #LLM #MachineLearning #Python #LangChain #OpenAI #SoftwareEngineering #AI #TechTutorial #Automation


This content originally appeared on DEV Community and was authored by Vansh Saxena