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ExplainersHow agent systems work

How agent systems work

An agent is not magic. It is a loop: read context → decide the next step → maybe call a tool (search, API, file, database) → read the result → repeat until the task is done or you stop it.

An agent system is when you wire several of those loops together with rules: who plans, who executes, what they’re allowed to touch, and how they hand work off.

The five pieces (plain-language map)

  1. Planner — breaks a fuzzy goal into steps (“research competitors → summarize → draft email”). Often uses a stronger model because ambiguity is expensive to handle badly.
  2. Executor — runs long tool chains (many API calls, edits, subtasks). Often uses a model that is fast and good at following instructions, not necessarily the smartest on the market.
  3. Tools — anything that connects the model to the real world: HTTP APIs, browser automation, Slack, your CRM, code execution. Without tools, the agent is just chat.
  4. Memory — short-term (what’s in the chat window) and long-term (vector DB, files, Postgres). Models forget; memory is how you keep continuity across sessions.
  5. Orchestrator — the manager that assigns roles, tracks tasks, enforces budgets, and writes an audit trail. In products, this is often a framework or custom service — not a single chat thread.

Orchestration in one picture

A serious stack usually looks like “a small team of agents”:

  • Roles (researcher, writer, reviewer, …)
  • A task queue or board + status
  • Spend caps and logs so parallel runs do not silently drain the budget
  • Optional schedules so work continues without someone typing in a chat box each time

Your IDE or a coding assistant can be one agent in that system; the orchestrator is what turns separate chats into something you can operate and debug.

What to say in a client meeting

  • “We separate planning from execution and from high-volume work so cost and reliability stay under control.”
  • “Tools are contracts: we decide what the agent can do; we log it; we can turn it off.”
  • “Without an orchestration layer, you don’t have a product — you have a demo.”
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NotebookLMModels and routing