Eight terms you will meet in any agent project, with plain definitions.
- AI agent
- An AI agent is a software system that pursues a goal by deciding its own next step. It plans, calls tools, reads the result, and repeats until the goal is met.
- Multi-agent system
- A multi-agent system splits a job across several specialized agents, each owning a narrow task. An orchestrator routes work between them and assembles the result. The pattern is used when one agent with one long prompt becomes unreliable or too slow.
- Orchestration
- Orchestration is the control layer that decides which agent, tool, or model call runs next.
- Tool use
- Tool use is a model calling an external function, API, database, or application on your behalf.
- Retrieval-augmented generation (RAG)
- Retrieval-augmented generation fetches passages from your own documents and passes them to the model as context. RAG grounds an answer in source material, which is what makes citations possible.
- Vector database
- A vector database stores text, images, or records as numeric embeddings. They can then be searched by meaning, not just by exact keyword.
- Human-in-the-loop
- Human-in-the-loop means a person reviews, approves, or overrides the agent at a checkpoint before an action becomes final.
- Closed-loop evaluation
- Closed-loop evaluation tests an agent against explicit review criteria and feeds the results back into the system. The loop closes when that output changes the prompts, tools, or routing.
Cost, timelines, integration, and security are covered in the agentic AI and AI agent development FAQ.