I was testing Gemini 3 Pro Preview on Vertex AI using the retreival tool (Vertex AI Search Datastore) together with a structured output.
The used library version is "@google/genai": "^1.30.0",
The response I got was a markdowned json, which followed the defined structured output schema, but not a json which could be parsed directly.
It is essential that the model adheres to the configured specifications.