I have two GCP projects under the same VPC:
Project A — ADK agent deployed on Vertex AI Agent Engine
Project B — MCP server deployed on Cloud Run, exposed via an Apigee proxy URL
Configuration:
Cloud Run is set to internal ingress only, with no authentication
Both projects are under the same VPC
A service account with the necessary permissions is in place
The problem:
When the agent runs locally, it connects to the MCP server successfully via the Apigee URL. When deployed on Vertex AI Agent Engine, it fails with an error saying MCPToolset not found / unable to get MCPToolset.