FYI, the upcoming version of gpt4 does considerably worse emulating function calls / generating code-like strings, but gets better again if you switch to the function call API: https://twitter.com/reissbaker/status/1671361372092010497

(My guess is the same is true of gpt-3.5, although I haven't tested it.)

That being said, Langchain has a nearly drop-in replacement if you want to start using the function call API: https://python.langchain.com/docs/modules/agents/agent_types...

Are there any useful alternative models though? Most I've found weren't particularly good at following instructions or using tools in the way langchain provides them.