Option A implements an iterative orchestrator-worker loop in which synthesis is treated as an evaluation checkpoint rather than an irreversible transition to report generation. When synthesis identifies missing evidence, the coordinator can formulate focused follow-up tasks, send them to the agents with the appropriate tools, and repeat synthesis after receiving the additional findings.

Anthropic’s multi-agent research architecture follows this pattern: the lead agent synthesizes subagent findings and determines whether further research is required. If gaps remain, it creates additional subagents or refines the research strategy. This preserves specialization and centralized control.

Option B makes the incompleteness visible but does not improve research coverage. Option C may increase initial cost without guaranteeing that the specific gaps discovered during synthesis will be addressed. Option D weakens separation of concerns by giving the synthesis agent search capabilities that belong to the research specialists. Targeted redelegation is more efficient because the second research round is informed by concrete deficiencies rather than speculative breadth. It also allows the coordinator to track completeness explicitly before authorizing final report generation.

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