Day 3 , Subagents & Teams

Today is where Claude Code stops being a single developer and starts being a coordinator. Subagents let you split work across multiple Claude sessions running in parallel, each with its own context window, tool permissions, and model. Built-in subagents handle common patterns (research, planning, general tasks) out of the box. Custom subagents give you specialized workers with restricted toolsets. Agent teams coordinate multiple peers against a shared plan. And the permissions system controls what every agent can and cannot do.

What you'll have by the end of today

• The Explore and Plan built-in subagents working on research and planning tasks
• At least one custom subagent with a restricted toolset and a specific model
• An agent team running with coordinated peers sharing a task list
• Background agents running independent sessions in parallel
• A permissions configuration that gates tool access by agent role

Lessons

1. Built-in Subagents , Explore, Plan, General-purpose, and the hidden agents that power the status line and guides
2. Custom Subagents , writing .claude/agents/<name>.md files with YAML frontmatter to create specialized workers
3. Agent Teams , --teammate-mode for coordinated peers, shared task lists, and the lead-agent pattern
4. Background Agents , --agent-view and parallel independent sessions that run while you keep working
5. Permissions & Security , permission modes, tool allow/deny lists, disabling subagent delegation, and environment variables that lock things down

Next: Day 4 , MCP, Plugins & Integration