    def _generate_tool_call_response(self) -> BetaMessageParam | None:
        content = self._get_last_assistant_message_content()
        if not content:
            return None

        tool_use_blocks = [block for block in content if block.type == "tool_use"]
        if not tool_use_blocks:
            return None

        results: list[BetaToolResultBlockParam] = []
…
                tool = self._tools_by_name.get(tool_use.name) if tool_use.name in available else None
…
                if tool is None:
…
                    result = {
                        "type": "tool_result",
                        "tool_use_id": tool_use.id,
                        "content": f"Error: Tool '{tool_use.name}' not found",
                        "is_error": True,
                    }
                else:
                    with self._tool_use_span(self._client, tool, tool_use) as run:
                        run.result = result = self._run_tool(tool, tool_use)
…
            results.append(result)

        return {"role": "user", "content": results}

    def _run_tool(self, tool: BetaRunnableTool, tool_use: BetaToolUseBlock) -> BetaToolResultBlockParam:
        try:
            return {
                "type": "tool_result",
                "tool_use_id": tool_use.id,
                "content": tool_result_content(tool.call(tool_use.input)),
            }
        except ToolError as exc:
            return {
                "type": "tool_result",
                "tool_use_id": tool_use.id,
                "content": tool_error_content(exc),
                "is_error": True,
            }
        except Exception as exc:
            log.exception(f"Error occurred while calling tool: {tool.name}", exc_info=exc)
            return {
                "type": "tool_result",
                "tool_use_id": tool_use.id,
                "content": tool_error_content(exc),
                "is_error": True,
            }
Warm-up
