Claude Code ships with five built-in agent types: Explore, Plan, general-purpose, statusline-setup, and claude-code-guide. Most people know two of them. The other three run constantly and shape how much your sessions cost. This is the full catalog, what each one is for, and why knowing them changes how you read your own terminal.
The general-purpose agent in Claude Code is not the main agent and not something you pick. It is a built-in subagent Claude routes to on its own for complex, multi-step work. It inherits your model and, in current Claude Code, spawns as a fork of your conversation. This post explains how it actually works and what that costs you.
A subagent in Claude Code is a specialized worker that runs in its own fresh, isolated context window, with its own tools and permissions, and reports back only a summary. It is how Claude does a noisy side task without flooding your main conversation. Here is what a subagent is, what file defines it, and when it earns its cost.
Subagent, parallel agent and skill get used as if they mean the same thing in Claude Code. They do not. A skill is reusable instructions that cost almost nothing until invoked. A subagent is delegated work in a fresh isolated context. Parallel agent is not a primitive at all. Picking the wrong one wastes tokens or floods your context.