ML Engineers Using AI Agents in Production — What's Your Experience?

I've been experimenting with AI agents for a few internal workflows and the gap between demos and production has been larger than I expected.

The biggest challenges so far have been reliability, tool-calling failures, and evaluating whether an agent is actually improving outcomes versus adding complexity.

For those running agents in production:

• What use cases have delivered real value?
• Which frameworks are you using?
• What broke that you didn't expect?
• How are you evaluating performance and ROI?

Curious to hear both success stories and cautionary tales.