Option B eliminates an unnecessary agent boundary. The coordinator already possesses the accumulated findings and can answer a straightforward follow-up without serializing more than 80,000 tokens into a fresh subagent context, waiting for another model execution, and receiving the result back. Anthropic’s multi-agent research engineering guidance emphasizes scaling effort to task complexity: simple fact-finding or lightweight processing should use substantially fewer agents and tool calls than complex research. It also reports that multi-agent systems consume far more tokens than ordinary interactions, making avoidable delegation expensive and slow. Option A adds an interactive retrieval protocol between agents and additional round trips. Option C spends compute proactively on summaries that users may never request and creates cache-invalidation problems whenever findings change. Option D could reduce repeated input cost where caching is applicable, but the subagent still receives and processes an unnecessarily large context and still incurs spawning latency. Delegation is valuable when an isolated context or specialized capability materially improves the result. For a direct summary already supported by the coordinator’s active context, local handling is the faster and simpler architecture.

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