This is a submission for the Google Cloud NEXT Writing Challenge We Can Build AI Agents After Google Cloud NEXT ‘26 — But We Can’t Test or Debug Them At Google Cloud NEXT ‘26, we were handed something powerful: Systems that can plan, decide, collaborate, and act . With A2A enabling agent-to-agent communication, ADK accelerating agent development, and Vertex AI orchestrating intelligent workflows at scale, one thing is clear: We’ve entered the era of autonomous software. But beneath that progress lies a problem most developers haven’t fully processed: We can build these systems faster than we can understand, test, or debug them. The Hidden Engineering Crisis Traditional software depends on a simple guarantee: Same input → same output That’s what makes testing possible. Unit tests validate logic Regression tests ensure stability Bugs can be traced and fixed But AI agent systems don’t behave like that.…