Fast mcp and structured output #4002

Job	Run time
checks / pre-commit	36s
checks / readme-snippets	13s
checks / test (3.12, lowest-direct, ubuntu-latest)	54s
checks / test (3.10, highest, windows-latest)	2m 15s
checks / test (3.12, highest, ubuntu-latest)	51s
checks / test (3.10, highest, ubuntu-latest)	50s
checks / test (3.13, lowest-direct, windows-latest)	2m 31s
checks / test (3.13, lowest-direct, ubuntu-latest)	45s
checks / test (3.12, lowest-direct, windows-latest)	3m 58s
checks / test (3.12, highest, windows-latest)	3m 17s
checks / test (3.11, highest, windows-latest)	2m 59s
checks / test (3.11, highest, ubuntu-latest)	44s
checks / test (3.10, lowest-direct, windows-latest)	2m 33s
checks / test (3.13, highest, ubuntu-latest)	49s
checks / test (3.10, lowest-direct, ubuntu-latest)	49s
checks / test (3.11, lowest-direct, windows-latest)	2m 23s
checks / test (3.11, lowest-direct, ubuntu-latest)	44s
checks / test (3.13, highest, windows-latest)	2m 35s
	29m 46s

Provide feedback