fix: align MCPServer tool result shapes #2610

Job	Run time
checks / pre-commit	37s
checks / readme-snippets	11s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 0s
checks / test (3.10, locked, windows-latest)	1m 12s
checks / test (3.11, lowest-direct, windows-latest)	1m 16s
checks / test (3.13, lowest-direct, ubuntu-latest)	50s
checks / test (3.11, locked, windows-latest)	1m 25s
checks / test (3.10, locked, ubuntu-latest)	52s
checks / test (3.14, lowest-direct, ubuntu-latest)	49s
checks / test (3.11, locked, ubuntu-latest)	50s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 2s
checks / test (3.12, locked, windows-latest)	1m 31s
checks / test (3.10, lowest-direct, windows-latest)	1m 14s
checks / test (3.12, locked, ubuntu-latest)	59s
checks / test (3.14, locked, ubuntu-latest)	1m 55s
checks / test (3.12, lowest-direct, ubuntu-latest)	57s
checks / test (3.13, lowest-direct, windows-latest)	1m 32s
checks / test (3.12, lowest-direct, windows-latest)	1m 20s
checks / test (3.13, locked, windows-latest)	1m 24s
checks / test (3.13, locked, ubuntu-latest)	45s
checks / test (3.14, locked, windows-latest)	2m 7s
checks / test (3.14, lowest-direct, windows-latest)	1m 14s
all-green	3s
	25m 5s

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