Agentic AI Architecture
Agentic AI is an architecture where an LLM acts as an autonomous agent. It plans and executes multi-step tasks with memory and tools.
Unlike a classic prompt→response app, an agentic system: - Sets sub-goals and decomposes tasks - Interacts with external tools / APIs - Iterates through a sense → plan → act → observe loop - Manages both short-term and long-term memory
Sections
| File | Topics |
|---|---|
| Fundamentals & Components | What agentic AI is, core components, ReAct loop, and how it differs from a plain LLM app |
| Multi-Agent Patterns | Main multi-agent patterns (Supervisor, Hybrid, BDI, Neuro-Symbolic) and coordination |
| Memory & RAG | STM/LTM, practical RAG pipeline, vector DB choices, retrieval methods |
| Tool Integration & Prompting | Function calling, tool registry, and prompting strategies (CoT, ReAct, ToT) |
| LLM Config & Security | Model settings, model selection, guardrails, and security threats like prompt injection |
| Testing & Observability | Metrics, test layers, observability, failure modes, production checklist |
| Agentic Search & Context Engineering (2025+) | Context engineering vs prompt engineering, multi-source retrieval, context failure modes, compression strategies, GraphRAG, governance |
| Vectorless RAG | Reasoning-based retrieval, hierarchical tree index, PageIndex, traditional vs vectorless comparison, hybrid approach |
Key Frameworks
| Framework | Maintainer | Strength | Typical Use Case |
|---|---|---|---|
| LangChain | LangChain Inc. | Tool use, chains, prompts, RAG | Chatbots, document Q&A, single-agent loops |
| LangGraph | LangChain Inc. | Stateful multi-agent graphs, cycles | Reflection loops, complex workflows |
| LlamaIndex | LlamaIndex | Enterprise data integration, RAG | Knowledge assistants over large corpora |
| AutoGen | Microsoft | Multi-agent group chats, code execution | Planning, multi-agent collaboration |
| CrewAI | CrewAI | Role-based agent teams | Business process automation |
| Semantic Kernel | Microsoft | .NET + Python, enterprise plugins | Enterprise AI assistants |
Choosing a framework: - Single agent with tools → LangChain - RAG over a large corpus → LlamaIndex - Multi-agent with group chats → AutoGen - Complex stateful workflows (reflection, branching) → LangGraph
Quick Start: Implementation Checklist
- Define Goals — clearly state objective and scope
- Select Components — LLM + vector DB + tools
- Design Architecture — perception -> planner -> executor -> memory -> observer
- Prototype Agent Loop — minimal ReAct with 1-2 tools
- Integrate RAG — embedding model + vector store
- Add Memory — LTM via vector DB, define promotion rules
- Implement Orchestration — supervisor logic or workflow engine
- Setup Prompt Strategy — system prompt, tool schemas, few-shot examples
- Configure LLM — temperature, token limits, loop caps
- Add Guardrails — loop limits, input sanitization, logging
- Test Thoroughly — unit, integration, scenario, adversarial
- Monitor & Iterate — observability, logs, metrics, refinement
Architecture Overview
User Input
│
▼
┌───────────────────────────────────────────────┐
│ Agent Core │
│ Perception → Planner → Executor → Observer │
│ ↕ Short-Term Memory (Context) │
└───────────────┬───────────────────────────────┘
│
┌────────┴────────┐
▼ ▼
Long-Term Memory External Tools
(Vector DB + RAG) (APIs / Code)