Your agentic loop is configured with the stop sequence "###END###". A response arrives with stop_reason: "stop_sequence" and no tool_use blocks. What should the orchestrator do?
Answer: Treat the response as complete and return it to the caller — same as end_turn
stop_sequence fires when one of your configured stop sequences appears in the output. Unless your loop has special logic tied to which sequence fired, treat it the same as end_turn: the response is complete, return it. Stop sequences are not tool calls — they cannot be executed. The response should always be appended regardless of stop_reason.