Method run_turn

tutorials/18_design_patterns_for_agents.py:973–1039

完整的 agentic loop: 1. 用户输入 → 消息列表 2. 调 API → 得到 assistant 回复 3. 有工具调用? → 权限检查 → 执行 → 结果回消息 4. 没有工具调用? → 返回文本 5. 重复 2-4 直到无工具调用或达到上限

(self, user_input: str)

            self.messages: list[dict] = []

        def run_turn(self, user_input: str) -> str:
            """
            完整的 agentic loop:
            1. 用户输入 → 消息列表
            2. 调 API → 得到 assistant 回复
            3. 有工具调用? → 权限检查 → 执行 → 结果回消息
            4. 没有工具调用? → 返回文本
            5. 重复 2-4 直到无工具调用或达到上限
            """
            self.messages.append({"role": "user", "content": user_input})
            log = []

            for iteration in range(1, self.max_iterations + 1):
                # 调 API
                events = self.api.stream(self.system_prompt, self.messages)

                # 解析 events
                text_parts = []
                tool_calls = []
                for event in events:
                    if event["type"] == "text":
                        text_parts.append(event["text"])
                    elif event["type"] == "tool_use":
                        tool_calls.append(event)

                assistant_text = "".join(text_parts)
                self.messages.append({
                    "role": "assistant",
                    "content": assistant_text,
                    "tool_calls": tool_calls,
                })

                # 无工具调用 → 结束
                if not tool_calls:
                    log.append(f"    [迭代 {iteration}] 纯文本回答, 循环结束")
                    for line in log:
                        print(line)
                    return assistant_text

                # 有工具调用 → 权限 + 执行
                for call in tool_calls:
                    allowed, reason = self.permission.check(call["name"])

                    if allowed:
                        result = self.tools.execute(call["name"], call["input"])
                        is_error = result.startswith("ERROR:")
                        log.append(
                            f"    [迭代 {iteration}] {call['name']}"
                            f"({call['input'][:30]}) → {result[:50]}"
                        )
                    else:
                        result = reason
                        is_error = True
                        log.append(
                            f"    [迭代 {iteration}] {call['name']} → 拒绝: {reason}"
                        )

                    self.messages.append({