The core components of ai agent building are an LLM, tools, memory, orchestration, and evaluation. These building blocks are reused whether you want one working agent or many agents across a team.
1. AI models
As of June 2026, teams often prototype with capable models such as GPT-5.2, Claude Opus 4.6, Claude Sonnet 4.6, Gemini models, or earlier options like GPT-4.1 and Claude 3.5 where they still fit cost and latency needs. Prototyping with a capable model establishes a performance baseline before deployment.
2. Tools and APIs
Integrating APIs enables AI agents to autonomously invoke external tools. These may include email, calendar, CRM, search, payment, cloud storage, or internal databases.
3. Memory and datastores
Datastores provide additional knowledge for AI agents. AI agents should access relevant data sources for effective responses, and AI agents may need access to real-time information sources when stale answers create risk.
4. Orchestration
AI agent frameworks provide modular components for building workflows. LangChain is a popular orchestration framework for AI agents, while LangGraph is often used when teams need state, branching, and human review. A modular architecture allows for tailored capabilities and better documentation of interfaces.