This is a bug. The Gemini chat model node cannot call Google-related tools but works with other ones like Calculator and Wikipedia. The Google tool just needs to be connected to a Gemini agent for the flow to break.
[GoogleGenerativeAI Error]: Error fetching from https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:streamGenerateContent?alt=sse: [400 Bad Request] * GenerateContentRequest.tools[0].function_declarations[0].parameters.properties[Tool_Parameters].type: must be specified when not using one_of, any_of or all_of fields *
The error occurs when using the Google Models. The Model cannot take parameters from AI either using the {{ $fromAI() }} function or magic by the model.