You are building a multi-agent research system using the Claude Agent SDK.

Option B expresses both independent delegations in the same orchestration turn, allowing the runtime to execute them concurrently and return their results together. The current Claude Agent SDK calls the subagent-spawning capability the Agent tool; Task is its former name. Anthropic’s SDK subagent documentation explicitly identifies parallel analysis as a primary subagent use case. Claude tool responses can also contain multiple tool_use blocks , enabling independent calls to be handled as one parallel group rather than as serial model turns. Option A shortens each execution but does not remove the unnecessary wait between them and may reduce analysis quality. Option C provides useful behavioral guidance, but instructions alone do not establish the required response structure; the coordinator must actually emit both calls together. Option D duplicates coordinator execution, complicates state management, and creates unnecessary aggregation work. The correct flow is parallel fan-out from one coordinator, followed by a synchronization point that validates both results before synthesis begins. Failures should be tracked independently so that only the unsuccessful branch requires retrying.

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