A logistics company's planning agent must work with a carrier partner on complex multi-leg shipments. The partner runs its own agent that checks live capacity, negotiates alternatives and books slots with tools the company cannot access. The company also needs to look up a shipment's current status from the partner's tracking API. Which combination is most appropriate?

Answer: A — Agent-to-agent delegation for multi-leg planning with a defined task contract, and a direct tool for status lookup

Planning needs the partner's own reasoning and tools, which fits agent-to-agent delegation with a clear contract on inputs, authority, timeouts and validation. Status lookup is deterministic, so a direct tool is simpler, faster and testable. (b) wraps a simple lookup in a non-deterministic agent. (c) duplicates logic and lacks the partner's private tools and data. (d) misuses stdio for a cross-organization service and can't reach the partner's capabilities.