Chapter 5: Agents, Subagents, and Planning

Welcome to Chapter 5: Agents, Subagents, and Planning. In this part of OpenCode Tutorial: Open-Source Terminal Coding Agent at Scale, you will build an intuitive mental model first, then move into concrete implementation details and practical production tradeoffs.

OpenCode includes distinct agent behaviors that should be chosen intentionally by task type.

Built-in Agent Modes

Agent	Strength
build	full-access implementation and execution
plan	read-only analysis and exploration
general (subagent)	complex search and multi-step discovery

Mode Selection Heuristic

• use plan for unfamiliar codebases and risk analysis
• switch to build only when plan quality is acceptable
• use general for deep discovery and context prep

Review Pattern

1. ask plan to map scope and risks
2. confirm constraints and test strategy
3. hand off to build for implementation
4. validate and finalize with tests and diff review

Source References

• OpenCode Agents Documentation
• OpenCode README

Summary

You can now use OpenCode modes as a controlled workflow, not just a toggle.

Next: Chapter 6: Client/Server and Remote Workflows

How These Components Connect

flowchart LR
    A[Task Input] --> B{Agent Mode}
    B -->|plan| C[Planning Agent]
    B -->|build| D[Build Agent]
    C --> E[Step-by-step Plan]
    D --> F[Subagent Dispatch]
    F --> G[File Tools]
    F --> H[Shell Tools]
    E --> I[Human Review]