Proper handle extra data in MCP objects #304

Job	Run time
checks / pre-commit	35s
checks / readme-snippets	10s
checks / test (3.12, locked, ubuntu-latest)	54s
checks / test (3.10, locked, ubuntu-latest)	45s
checks / test (3.10, lowest-direct, ubuntu-latest)	44s
checks / test (3.10, locked, windows-latest)	2m 16s
checks / test (3.10, lowest-direct, windows-latest)	2m 31s
checks / test (3.12, lowest-direct, windows-latest)	3m 37s
checks / test (3.11, locked, ubuntu-latest)	44s
checks / test (3.11, lowest-direct, windows-latest)	2m 44s
checks / test (3.13, lowest-direct, ubuntu-latest)	46s
checks / test (3.13, locked, windows-latest)	2m 31s
checks / test (3.11, lowest-direct, ubuntu-latest)	49s
checks / test (3.14, lowest-direct, windows-latest)	2m 23s
checks / test (3.14, locked, ubuntu-latest)	2m 21s
checks / test (3.11, locked, windows-latest)	2m 39s
checks / test (3.12, locked, windows-latest)	3m 31s
checks / test (3.14, locked, windows-latest)	3m 6s
checks / test (3.13, locked, ubuntu-latest)	46s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 17s
checks / test (3.13, lowest-direct, windows-latest)	4m 41s
checks / test (3.12, lowest-direct, ubuntu-latest)	48s
all-green	3s
	40m 41s

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