In support of our mission to accelerate the developer journey on Google Cloud, we built Dev Signal: a multi-agent system designed to transform raw community signals into reliable technical guidance by automating the path from discovery to expert creation. In the first three parts of this series, we laid the essential groundwork by establishing its core capabilities and local verification process: In part 1 , we standardize the agent's capabilities through the Model Context Protocol (MCP), connecting it to Reddit for trend discovery and Google Cloud Docs for technical grounding. In part 2 , we built a multi-agent architecture and integrated the Vertex AI memory bank to allow the system to learn and persist user preferences across different conversations. In part 3 , we verified the full end-to-end lifecycle locally using a dedicated test runner to ensure that research, content creation, and cloud-based memory retrieval were perfectly synchronized.…