# X_SCHEMA_DEFAULT_UNSHAREABLE

## Means

a schema default cannot be copied per parse

## Typical cause

`.default(value)` where `value` holds a function, a symbol or anything else `structuredClone` refuses. Every parse that omits the field must receive its OWN copy — one shared object meant a handler's mutation became the next request's starting value — so a default that cannot be copied is refused where it is WRITTEN, at the first import of the authoring file, rather than shared and bled

## Fix

pass a JSON-shaped default (plain object, array, `Date`, `Map`, `Set`), or drop `.default()` and answer the absent value in the handler

[Schema and validation](/error-codes#schema-and-validation)