Google’s Agent Stack: ADK, Agent Runtime, and the Names That Keep Moving

Google ships the agent stack in two halves: ADK, an open-source, five-language framework you can run on your laptop, and a managed platform — Agent Runtime, Sessions, Memory Bank, Agent Gateway — that runs it for you. Learn the pieces, the ADK vocabulary, the runtime’s operational and billing shape, Google’s A2A posture, and the guardrails that actually bind — with the branding churn labelled honestly.

Content current as of 2026-09.

Lessons

1. The stack: umbrella, framework, runtime
2. ADK, in enough depth to read the docs
3. Agent Runtime: sessions, memory, deploys, meter
4. A2A: Google wrote it, then gave it away
5. Guardrails, governance, and the build-vs-buy call