GroupChat UserProxyAgent improvements.

[afourney]

There are many subtleties in getting GroupChat to operate optimally. One of these subtleties is how GroupChat interacts with the UserProxyAgent (or similar). Specifically, agents are selected to speak based on their names and system messages -- but the UserProxyAgent has an empty system message because, in its default configuration, it doesn't call an LLM. This can lead to suboptimal orchestration. Possible corrective actions include:

• Improve Group Chat Documentation, including a detailed description of how agents are selected, and how termination is handled
• Add a warning or exception in cases where an agent with an empty name or system message is added to the Group Chat (since these are critical parameters)
• Add a default system prompt to the UserProxyAgent. It won't be used in most cases, because it has no llm_config. But it's critical for GroupChat

[thinkall]

We are closing this issue due to inactivity; please reopen if the problem persists.