Raw LLM Responses

What Im wondering is, how does the model know what exactly to output when it wants to invoke a tool? Should it write e.g. //browser search(...) and that triggers the actual tool? Maybe the "how to invoke" bit is finetuned into the model?! Edit: Just researched a little, and found out, that the tools used, as well as the input parameters are part of the response you get from openai. When you send a message to openai, in the request-body, all the tools will be specified and the response will contain a tool_call object, if the model wants to use a tool. https://platform.openai.com/docs/guides/function-calling Not quite sure why they specifically explain all the tools again in the system prompt. Maybe this just improves the tool usage.