Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
SchemasArea: what it touches
Internal ChangesKind: in v2.1.285,
Internal ChangesSection of the release
What
Claude Code includes a library called zod to describe the shape of data, such as the inputs a tool accepts. That library was updated. Converting to JSON Schema, a standard format for describing data, now merges combined schemas, simplifies choices between plain types, and escapes references. Converting from JSON Schema now handles lists with optional items, rules on property names and fixed leading items.
Why
The way tool and MCP server input formats are translated may change in small ways.
