Sub-Agent Strategy

This is an operational strategy that agents receive via .thrum/strategies/. It describes when and how to delegate work to sub-agents to maximize parallelism and keep your main context focused.

Delegate research, independent tasks, and verification to sub-agents. Your main context should focus on task coordination, dependency management, and cross-cutting decisions.

Principles

Parallelize independent tasks — When multiple unblocked tasks touch different files/packages, implement them simultaneously via sub-agents
Delegate research — Spawn sub-agents to explore unfamiliar code before implementing, rather than reading it into your context
Verify in background — Run tests and lint via background sub-agents while you continue with the next task
Focused prompts — Give each sub-agent the full task description, worktree path, quality commands, and expected deliverables

Agent Selection

Task	Agent Type	Model	Background?
Implement a complex task	`general-purpose`	sonnet	no*
Implement a simple task	`general-purpose`	haiku	no*
Explore unfamiliar code	`Explore`	sonnet	yes
Run tests / lint	`general-purpose`	haiku	yes
Review implementation	`feature-dev:code-reviewer`	sonnet	no
Doc updates / config tweaks	`general-purpose`	haiku	yes

*Use foreground when you need the result before proceeding. Use background when you can continue other work while they run.

When to Parallelize vs. Work Sequentially

Parallel (sub-agents):

Tasks touching different files/packages with no shared state
Independent verification (tests, lint, coverage)
Research into multiple unrelated code areas
Doc/config updates alongside implementation

Sequential (direct work):

Tasks modifying shared files or depending on prior task output
Tasks requiring deep context from current session's changes
Tasks needing judgment calls mid-implementation
Single remaining task (no parallelism benefit)

Verifier Sub-Agent Pattern

After completing a task, spawn a background sub-agent to independently verify:

Run the test suite and confirm all pass
Review implementation against the task description
Check code follows project conventions
Confirm acceptance criteria are met

This lets you start the next task immediately while verification runs in parallel.

Sub-Agent Prompt Guidelines

When writing prompts for sub-agents:

Include the full task description with acceptance criteria
Specify the absolute worktree path (sub-agents cannot resolve relative paths)
Provide the exact quality commands to run (make test, make lint, etc.)
State the expected deliverables explicitly
Sub-agents cannot access MCP tools — they fall back to Bash
Sub-agents cannot see CLAUDE.md or project .agents/ files unless you include the content in the prompt

Next Steps

Agent Coordination — higher-level coordination patterns including how to use sub-agents alongside Thrum messaging
MCP Server — the message-listener pattern, which runs a background sub-agent to block on wait_for_message
Workflow Templates — how the design → plan → implement pipeline uses sub-agents for parallel implementation
Claude Code Plugin — the plugin that provides sub-agent spawning templates via the background listener pattern