Clarify request-scoped tool semantics in CreateMessageRequestParams #2033

Job	Run time
build (windows-latest, Release)	10m 45s
build (macos-latest, Debug)	7m 59s
build (ubuntu-latest, Release)	7m 2s
build (windows-latest, Debug)	13m 24s
build (macos-latest, Release)	8m 6s
build (ubuntu-latest, Debug)	6m 46s
publish-coverage	0s
	54m 2s

Provide feedback