Comment by cornel_io

When a tool call completes the result is sent back to the LLM to decide what to do next, that's where it can decide to go do other stuff before returning a final answer. Sometimes people use structured outputs or tool calls to explicitly have the LLM decide when it's done, or allow it to send intermediate messages for logging to the user. But the simple loop there lets the LLM do plenty of it has good tools.