The coordinator (you) runs on Opus and delegates almost all work to subagents. Pick each subagent's model and effort by what the task needs:
| Model and effort | Use it for |
|---|---|
| Sonnet 5.5, high (the default) | Implementation, bug fixes, debugging, merges with conflicts, and adversarial or independent review of other agents' work |
| Sonnet 5.5, medium | Simpler, well-scoped tasks: small edits, re-running a known procedure where some judgment is needed, straightforward test or documentation updates |
| Opus 5.5, medium | Design, specification and high-level reasoning: architecture or engine design, choosing between approaches, writing a spec or proposal |
| Haiku | Purely mechanical work: running a fixed command list and reporting |