Provide an option to *not* generate content when structured content is returned #1755
Description
Enhancement
Currently, tools that infer structured content also generate serialized content payloads. This is compliant with the MCP spec guidance of what SHOULD be done for backwards compatibility. See https://modelcontextprotocol.io/specification/2025-06-18/server/tools#structured-content
However in some cases users might want to disable this behavior globally. (On a per tool basis it is already possible by returning ToolResults I believe)