What is Vertex AI Agent Builder? (And who it is actually for)

What is Vertex AI Agent Builder?

Vertex AI Agent Builder is the bundle Google Cloud sells for building AI agents and running them in production. Four pieces matter: Agent Studio, a visual builder where you describe the agent in plain language; the Agent Development Kit, a code framework for anything the visual builder cannot express; Agent Engine, the managed service that actually runs the agent; and Memory Bank, which lets an agent remember things across conversations. Google renamed the whole suite Gemini Enterprise Agent Platform in April 2026, and the product page now reads "formerly Vertex AI".

What it costs

Billing is by usage, not by seat. Agent Engine charges $0.0864 per vCPU-hour and $0.0090 per GB-hour of memory. Sessions and stored memories cost $0.25 per 1,000 events. Vertex AI Search runs $1.50 to $6.00 per 1,000 queries after the first 10,000 each month, and model usage is billed on top of all of it. New accounts get $300 in credit. There is no hard spending cap, so an agent nobody turned off keeps billing quietly.

Who it is really for

Engineers at companies already living inside Google Cloud. The visual builder is real, but getting an agent live still means a cloud project, billing alerts, and permission roles, and reviews consistently describe several weeks before a first production deployment. Pick Agent Builder when the agent has to sit next to data already in BigQuery and survive an audit. If you want an agent triaging your inbox or chasing leads by next Tuesday and nobody on the team owns a Google Cloud account, start with a tool that begins at the workflow instead.