AI Agents intro
π― Beyond Chat: AI That Actually DOES Things
Imagine pannunga β nee boss kitta solra: "Next quarter budget report prepare pannu." Boss enna pannuvaanga?
Bad employee (Regular Chatbot):
"Budget report prepare pannanum na, first financial data collect pannanum, then Excel la organize pannanum..." β process EXPLAIN pannuvaanga but actually DO pannaadhaa! π€
Good employee (AI Agent):
- Finance team kitta email anuppi data vaanguvanga
- Last quarter report open pannittu template eduppanga
- Numbers calculate pannuvanga
- Charts create pannuvanga
- Report draft pannuvanga
- Review ku un inbox la send pannuvanga
Paattheenga vithyaasam? One explains, the other EXECUTES. That's the difference between a chatbot and an AI Agent.
AI Agent = LLM + Tools + Autonomous Decision Making
Regular LLM: "Here's how you could search the web for..."
AI Agent: *Actually searches the web, reads results, synthesizes answer* β
2025-26 la AI Agents is THE hottest topic in AI. OpenAI, Google, Anthropic β ellarum agent frameworks build pannuraaanga. Why? Because the jump from "AI that talks" to "AI that works" is MASSIVE.
Indha article la cover pannuvom:
- Agent architecture β eppadi think pannum, eppadi act pannum
- ReAct pattern β the brain behind agents
- Tool use β web search, code execution, API calls
- Multi-agent systems β team of AI agents working together
- Real code examples β build un own agent
- Safety & guardrails β agents go wrong aagaamal eppadi prevent pannum
π Agent Architecture: Think β Plan β Act β Observe
AI Agent-oda core loop is simple β TPAO cycle:
Think β What should I do? What's the current state?
Plan β Which tool should I use? What's my next step?
Act β Execute the tool/action
Observe β What was the result? Am I done?
Agent Components:
| Component | Role | Example |
|---|---|---|
| **Brain (LLM)** | Reasoning & decision making | GPT-4, Claude |
| **Memory** | Stores conversation & context | Chat history, vector store |
| **Tools** | External capabilities | Web search, calculator, APIs |
| **Planning** | Task decomposition | Break big goal into steps |
| **Execution** | Run actions | Call APIs, write files |
How an agent answers "What's the weather in Chennai and should I carry an umbrella?":
Key difference from regular prompting: The LLM DECIDES to call the weather tool. Nobody told it to. It analyzed the question, realized it needs current data, chose the right tool, called it, interpreted results, and answered. Autonomous decision-making β that's what makes it an agent!
Agent β pre-programmed workflow. A workflow says "always do step 1, then step 2." An agent says "given the situation, what's the best next step?" Agents are dynamic, not scripted.
ποΈ Agent Architecture Diagram
```
AI Agent Architecture β The Agentic Loop
βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ
βββββββββββββββββββββββ
β USER GOAL β
β "Book a flight to β
β Delhi under βΉ5000" β
ββββββββββββ¬βββββββββββ
β
βΌ
ββββββββββββββββββββββββββββββββββ
β AGENT BRAIN (LLM) β
β β
β βββββββββββββ βββββββββββββββ β
β β THINK β β MEMORY β β
β β Reasoning β β Past steps, β β
β β What next?β β context β β
β βββββββ¬ββββββ βββββββββββββββ β
β β β
β βββββββΌββββββ β
β β PLAN β β
β β Pick tool β β
β β & params β β
β βββββββ¬ββββββ β
ββββββββββΌβββββββββββββββββββββββββ
β
ββββββββββββΌβββββββββββ
β TOOL EXECUTOR β
β β
βββββββββββΌββββββββββββββββββββββΌββββββββββ
β β β β
βΌ βΌ βΌ βΌ βΌ
βββββββ βββββββββ βββββββββ βββββββββ ββββββββ
β Web β β Code β β API β β File β β DB β
βSearchβ βRunner β βCaller β βSystem β βQuery β
ββββ¬βββ βββββ¬ββββ βββββ¬ββββ βββββ¬ββββ ββββ¬ββββ
β β β β β
ββββββββββ΄βββββββββ΄ββββββββββ΄βββββββββ
β
ββββββββΌβββββββ
β OBSERVE β
β Result OK? β
β Goal met? β
ββββββββ¬βββββββ
β
ββββββββΌβββββββ
NO β DONE? β YES β Final Answer
ββββββ Goal met? ββββββββββββββββββββββΆ π€
β βββββββββββββββ
β
ββββββββΆ Back to THINK (loop continues)
```
**Agent keeps looping** β Think β Plan β Act β Observe β until goal is met or max iterations reached.π§ ReAct Pattern: Reasoning + Acting
ReAct (Yao et al., 2022) is THE most important agent pattern. It interleaves reasoning (chain-of-thought) with actions (tool use).
ReAct Format:
Real Example β "Compare NVIDIA and AMD stock prices this week":
Why ReAct works:
- Transparent reasoning β nee agent-oda thought process paakkalaam
- Error recovery β oru tool fail aana, agent think pannittu alternative try pannum
- Grounded answers β tool results la based, not hallucination
- Debuggable β which step la wrong aachunu easy-a identify pannalaam
Without ReAct (just acting): Agent blindly calls tools without thinking β wrong tools, wrong order, wasted calls
Without ReAct (just thinking): Agent reasons well but can't access real-time info β outdated/hallucinated answers
ReAct = Best of both worlds π§ π§
π§ Tool Use: Giving AI Superpowers
Tools transform LLMs from "text generators" to "capable workers." Let's see how tool use works:
OpenAI Function Calling (Tool Use):
Common Agent Tools:
| Tool | What It Does | Example |
|---|---|---|
| **Web Search** | Search internet | Google, Bing, Tavily |
| **Code Interpreter** | Run Python code | Calculate, analyze data |
| **File Operations** | Read/write files | Parse PDFs, create CSVs |
| **API Caller** | Hit external APIs | Weather, flights, CRM |
| **Database Query** | Run SQL queries | Customer lookup |
| **Email Sender** | Send emails | Notifications, reports |
| **Browser** | Navigate websites | Fill forms, scrape data |
Key insight: The LLM itself doesn't execute tools β it decides which tool to call and with what parameters. Your code executes the actual tool and returns results. LLM is the brain, tools are the hands. π§ β
π‘ Analogy: AI Agent = Smart Office Assistant
Think of an AI Agent as a new smart office assistant:
Regular AI (Chatbot) = Receptionist:
"How can I help you?" β You ask a question β They answer from memory β Done. They sit at the desk and respond. That's it.
AI Agent = Executive Assistant:
You say "Organize a team dinner for 10 people next Friday."
The EA doesn't just say "Here's how to organize a dinner." They:
1. Think: Need restaurant, budget, dietary restrictions, RSVPs
2. Check calendar: Is Friday free for everyone? (tool: calendar)
3. Ask team: Any dietary restrictions? (tool: email/slack)
4. Search: Best restaurants near office for 10 people (tool: search)
5. Compare: Price, reviews, availability (tool: reasoning)
6. Book: Make reservation (tool: API/phone)
7. Notify: Send invite to everyone (tool: email)
8. Report: "Done! Booked at Saravana Bhavan, 7 PM, βΉ500 per head" β
The EA uses MULTIPLE tools, makes DECISIONS at each step, handles UNEXPECTED situations (restaurant full? β try next one), and doesn't stop until the GOAL is met.
That's exactly what an AI Agent does β autonomous, multi-step, tool-using, goal-oriented execution. Not just answering questions, but completing tasks. π―
One more parallel: A great EA learns your preferences over time (memory). "Boss always prefers South Indian food, vegetarian, and early evening slots." AI Agents can do this too with persistent memory!
π₯ Multi-Agent Systems: Team of AI Agents
One agent is powerful. Multiple agents working together is game-changing.
Multi-Agent Concept: Instead of one agent doing everything, create specialized agents that collaborate.
Example β Content Creation Pipeline:
Popular Multi-Agent Frameworks:
| Framework | By | Best For | Complexity |
|---|---|---|---|
| **CrewAI** | Community | Role-based agent teams | Medium |
| **AutoGen** | Microsoft | Conversational agents | Medium |
| **LangGraph** | LangChain | Complex workflows | High |
| **OpenAI Swarm** | OpenAI | Lightweight handoffs | Low |
Multi-agent is like a company β each agent is a specialist. Instead of one person doing everything, you have a team where each member excels at their role. π’
π Agent Design Patterns
Different problems need different agent architectures. Common patterns:
1. Single Agent + Tools (Simplest)
Best for: Simple tasks, chatbots with capabilities
2. Chain Pattern (Sequential)
Best for: Pipelines (research β write β review)
3. Supervisor Pattern (Hierarchical)
Best for: Complex tasks needing coordination. Supervisor decides which worker to call.
4. Debate Pattern (Adversarial)
Best for: Decision making, reducing bias, quality improvement
5. Swarm Pattern (Dynamic)
Best for: Customer support (handoff from general β specialist)
Pattern Selection Guide:
| Pattern | Complexity | Reliability | Speed | Use Case |
|---|---|---|---|---|
| **Single Agent** | Low | High | Fast | Simple tasks |
| **Chain** | Medium | Medium | Slow | Content pipelines |
| **Supervisor** | High | High | Medium | Complex orchestration |
| **Debate** | Medium | Very High | Slow | Critical decisions |
| **Swarm** | High | Medium | Fast | Dynamic conversations |
Pro tip: Start with Single Agent + Tools. Pinna performance or complexity issues vantha, multi-agent patterns consider pannu. Over-engineering avoid pannu β simple agents are easier to debug! π―
π Agent System Prompt Template
π― Real-World Agent Use Cases
AI Agents are being deployed across industries. Real examples:
| Use Case | Agent Type | Tools Used | Impact |
|---|---|---|---|
| **Devin (AI SWE)** | Coding agent | Terminal, browser, editor | Writes & deploys code autonomously |
| **Auto-GPT** | General agent | Web, file, code | Autonomous task completion |
| **Customer Support** | Service agent | CRM, knowledge base, email | 60% ticket resolution without humans |
| **Data Analysis** | Analyst agent | SQL, Python, charts | Hours of analysis β minutes |
| **Sales Outreach** | SDR agent | CRM, email, LinkedIn | Personalized outreach at scale |
| **Code Review** | Review agent | Git, linter, tests | Automated PR reviews |
| **Travel Planning** | Booking agent | Flights, hotels, maps | End-to-end trip planning |
| **Research** | Research agent | Web, papers, citations | Literature review automation |
Indian Startup Examples:
| Startup | Agent Use Case | Status |
|---|---|---|
| **Ema** (Bengaluru) | Universal AI employee | $25M raised |
| **Composio** (Bengaluru) | Agent tool integrations | 100+ integrations |
| **Relevance AI** | No-code agent builder | Growing fast |
Real scenario β How an agent handles customer support:
3 tool calls, fully resolved, no human needed! That's agent power. π
β οΈ Agent Risks & Safety Guardrails
AI Agents are powerful but DANGEROUS without guardrails!
1. Infinite Loops π
Agent gets stuck: "I need to search" β search fails β "Let me try again" β fails β repeat forever. Fix: Set max_iterations (e.g., 10) and force stop.
2. Wrong Tool Calls
Agent decides to send email with wrong content, delete files, or call production APIs with bad data. Fix: Human-in-the-loop for destructive actions. Never give agents write/delete access without approval.
3. Hallucinated Actions
Agent "pretends" to call a tool and makes up the result instead of actually calling it. Fix: Always verify tool call was actually executed, don't trust agent's "observation" claims.
4. Cost Explosion πΈ
Each agent step = LLM API call. Complex task with 20 steps Γ GPT-4 = $0.50+ per task. Multi-agent with debate = $5+ per task. Fix: Use cheaper models for simple steps, set cost budgets.
5. Security Risks π
Agent with web access could be tricked by prompt injection in websites. Agent with code execution could run malicious code. Fix: Sandbox all tool executions, validate all inputs/outputs.
6. Unpredictable Behavior
Same prompt, different runs = different tool calls, different results. Non-deterministic. Fix: Temperature=0, detailed system prompts, evaluation pipelines.
Safety Checklist:
- β Maximum iteration limit (10-20)
- β Cost budget per task
- β Human approval for destructive actions
- β Sandboxed code execution
- β Input/output validation
- β Logging all agent steps for audit
- β Kill switch for runaway agents
π Why AI Agents Are the Future
2025-2026 is the "Year of Agents." Here's why this matters for your career:
The evolution of AI interfaces:
- 2022: ChatGPT β text in, text out (conversational)
- 2023: GPT-4 + plugins β text + tools (capable)
- 2024: Custom GPTs, Assistants API β configurable agents
- 2025-26: Autonomous agents β goal in, results out (agentic)
Every major company is betting on agents:
- OpenAI: "Agents are the killer app for AI" β Sam Altman
- Google: Gemini Agents, Project Mariner (browser agent)
- Anthropic: Claude computer use, tool use
- Microsoft: Copilot agents across Office, GitHub
- Apple: Siri with app-level agent actions
Job market impact:
| Role | Without Agent Skills | With Agent Skills |
|---|---|---|
| **AI Engineer** | βΉ15-25 LPA | βΉ30-50 LPA |
| **Full Stack Dev** | βΉ12-20 LPA | βΉ20-35 LPA |
| **Data Scientist** | βΉ15-25 LPA | βΉ25-40 LPA |
"Agent Engineer" is becoming a distinct role β companies hiring specifically for people who can design, build, and maintain AI agent systems.
What this means for you: If you can build reliable AI agents that actually complete tasks autonomously, you're in the top 5% of AI developers. Most developers can call an API β few can build a system that reasons, plans, uses tools, handles errors, and delivers results. That's the skill gap, and it's lucrative. π°
β π Key Takeaways
AI Agents β Remember These Points:
β Agent = LLM + Tools + Autonomous Loop β Not just chat, but think-plan-act-observe
β ReAct pattern is foundational β Interleave reasoning with tool use for reliable agents
β Tools give agents superpowers β Web search, code execution, APIs, databases
β Multi-agent > single agent for complex tasks β Specialized roles, collaborative execution
β Start simple β Single agent + 2-3 tools β then scale to multi-agent
β Safety is NON-NEGOTIABLE β Max iterations, human-in-loop, sandboxing, cost limits
β OpenAI function calling is the easiest way to start building agents
β CrewAI/LangGraph for production multi-agent systems
β Agent Engineer is a real job β High demand, high pay, few qualified people
β Debug by reading agent traces β Thought β Action β Observation logs tell you everything
π π Mini Challenge: Build Your First Agent
Challenge: Build a simple AI agent that can answer questions using web search!
Option 1: No-code (Easy)
- Go to ChatGPT β Create a Custom GPT
- Enable "Web Browsing" capability
- System prompt: "You are a research agent. For every question, search the web first, then answer with sources."
- Test with: "What are the top 5 AI startups in India in 2026?"
Option 2: Code (Intermediate)
Evaluation: Does your agent search before answering? Does it cite sources? Does it handle "I don't know" gracefully?
π€ Interview Questions on AI Agents
Prepare for these agent-related interview questions:
Q1: "What's the difference between an AI agent and a chatbot?"
A: A chatbot responds to individual messages. An agent has a goal, can plan multi-step approaches, use external tools, maintain state across steps, and make autonomous decisions. Chatbot = reactive, Agent = proactive and autonomous.
Q2: "Explain the ReAct pattern and why it's important."
A: ReAct interleaves Reasoning (Thought) with Acting (tool calls). Each cycle: Think about what to do β Execute a tool β Observe the result β Decide next step. It's important because pure reasoning without tools leads to hallucination, and pure tool use without reasoning leads to wrong tool choices.
Q3: "How would you prevent an agent from going into an infinite loop?"
A: Set max_iterations limit, implement cost budgets, add timeout per step, detect repeated actions (same tool call twice = stop), and include a "give up gracefully" instruction in the system prompt.
Q4: "When would you use multi-agent vs single agent?"
A: Single agent for straightforward tasks (up to 5-7 steps). Multi-agent when: tasks need different expertise (research vs writing), you need quality checks (writer + reviewer), tasks can be parallelized, or the complexity exceeds what one agent prompt can handle.
Q5: "What are the security concerns with AI agents?"
A: Prompt injection via tool outputs (malicious websites), unauthorized actions (sending wrong emails), data leakage (agent sharing private data with tools), cost attacks (triggering expensive tool calls), and privilege escalation. Mitigations: sandbox everything, validate I/O, human-in-the-loop for critical actions, principle of least privilege for tool access.
π Final Thought
AI Agents represent the shift from "AI as a tool" to "AI as a teammate." Today you prompt AI. Tomorrow, you'll give it goals and it'll figure out the rest.
The best part? We're at the very beginning of this revolution. Building agent skills now is like learning web development in 2005 β early movers will dominate. Start simple, build real agents, and ride this wave! π€π
π€οΈ Next Learning Path
Agents master pannaachu? Next steps:
- Building AI Apps with APIs β Turn your agents into real products users can interact with
- LangGraph Deep Dive β Complex agent workflows with state machines
- AI Cost & Performance β Optimize agent costs (each step costs money!)
- Computer Use Agents β Agents that control browsers and desktop apps
- Agent Evaluation β How to test and benchmark agent reliability
β FAQ
**ReAct pattern la "Observation" step enna pannum?**