The Built-in Subagents: Explore, Plan, General-Purpose
You're Already Using Subagents
Before you ever create a custom subagent, Claude Code is already delegating to built-in ones on your behalf. Understanding them shows you the patterns to copy — and each inherits the parent conversation's permissions with additional tool restrictions.
Claude Code delegates to three core built-in subagents, each with its own model and tool profile.
Explore — Fast, Read-Only Search
Explore is a fast, read-only agent optimized for searching and analyzing codebases. Claude delegates to it when it needs to understand code without changing it — keeping all those file reads out of your main context.
- •Model: Haiku (fast, low-latency) — cheap enough to read widely.
- •Tools: read-only (denied Write and Edit).
- •Purpose: file discovery, code search, codebase exploration.
- •Thoroughness levels Claude can request: quick (targeted lookup), medium (balanced), or very thorough (comprehensive).
A speed optimization worth knowing
Explore (and Plan) deliberately SKIP your CLAUDE.md files and the session's git status to stay fast and cheap. Every other built-in and custom subagent loads both. If a project rule must reach Explore, restate it in the delegation prompt.
Plan and General-Purpose
Plan is the research agent used during plan mode: when Claude needs to understand your codebase before presenting a plan, it delegates the research to Plan. It inherits your main model, is read-only, and — importantly — its existence helps prevent infinite nesting, because subagents cannot spawn other subagents.
General-purpose is the capable all-rounder for complex, multi-step tasks that need both exploration AND action. It inherits your main model and has access to all tools. Claude reaches for it when a task requires exploring, reasoning about results, and then making changes across multiple dependent steps.
| Built-in | Model | Tools | Best for |
|---|---|---|---|
| Explore | Haiku | Read-only | Fast codebase search & discovery |
| Plan | Inherit | Read-only | Research during plan mode |
| General-purpose | Inherit | All tools | Complex explore-and-act, multi-step work |
The three core built-in subagents at a glance. (Claude Code also has helper agents like statusline-setup and claude-code-guide.)
The No-Nesting Rule
One rule shapes the entire subagent system: subagents cannot spawn their own subagents. This prevents runaway recursion. It's why Plan exists as a dedicated read-only researcher for plan mode, and why — when you need multi-level delegation — you orchestrate from the main thread rather than nesting.
Remember this constraint
A subagent has no Agent/Task tool available to it. If your workflow seems to need a subagent that itself delegates, the answer is to chain subagents from the main conversation, or use Skills — not to nest. We'll return to this when we discuss scaling.
Next
You've seen the built-ins. Next: HOW Claude actually decides which subagent to use — the description-driven delegation that powers all of this.
Key Takeaways
- ✓Claude Code ships with built-in subagents it delegates to automatically; each inherits the parent's permissions plus extra tool restrictions.
- ✓Explore: Haiku, read-only, for fast codebase search; Claude can request quick/medium/very-thorough levels.
- ✓Plan: inherits the main model, read-only, used during plan mode to research before presenting a plan.
- ✓General-purpose: inherits the main model, has all tools, for complex multi-step explore-and-act tasks.
- ✓Explore and Plan deliberately skip CLAUDE.md and git status for speed — restate critical rules in the delegation prompt if needed.
- ✓Core rule: subagents cannot spawn subagents (no nesting); for multi-level work, chain from the main thread or use Skills.
Check Your Understanding
Test what you learned in this lesson.
Q1.Which built-in subagent is read-only and runs on Haiku for fast codebase search?
Q2.Why do Explore and Plan skip loading CLAUDE.md and git status?
Q3.Which built-in subagent should handle a complex task needing both exploration AND code changes?
Q4.What is the 'no-nesting' rule?
Practice This Lesson