Clarify request-scoped tool semantics in CreateMessageRequestParams (… #2047

Job	Run time
build (macos-latest, Release)	7m 31s
build (ubuntu-latest, Release)	6m 47s
build (macos-latest, Debug)	9m 5s
build (windows-latest, Debug)	9m 26s
build (ubuntu-latest, Debug)	7m 4s
build (windows-latest, Release)	10m 29s
publish-coverage	-1s
	50m 21s

Provide feedback