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'@modelcontextprotocol/core': patch
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Ensure `standardSchemaToJsonSchema` emits `type: "object"` at the root, fixing discriminated-union tool/prompt schemas that previously produced `{oneOf: [...]}` without the MCP-required top-level type. Also throws a clear error when given an explicitly non-object schema (e.g. `z.string()`). Fixes #1643.