Sending additional data to MCP server tool calls

[fthbrmnby]

I have a case where I need to send some additional data (e.g. context data) along with tool arguments to MCP servers' tool calls using dotnet. The data I want to send is not static, it might change per request so I cannot send as HTTP headers because there isn't a way to set HTTP headers per tool call request as far as I know. Is there a way to handle this?

I saw #2290 and tried to write a custom middleware where I intercept tool calls to modify the request, but could not found a way to pass the additional data I want to send to middleware or a property in the request object to set the values to MCP tool call.