name: sanity-schema-manager description: Manages schema lifecycle including scaffolding, safe field deprecation, and data migrations. Use when modifying existing schemas.

Schema Manager

This skill handles the lifecycle of Sanity Schema types.

Procedure

1. Scaffold (Create)

   • Use templates to create document, object, or singleton types.
   • Constraint: Ensure defineType and defineField are used.
   • Constraint: Ensure an icon is imported from @sanity/icons.

2. Deprecate (Update)

   • Ask: "Which field do you want to deprecate?"
   • Action: Apply the "ReadOnly -> Hidden -> Deprecated" pattern to the field definition.
   • Output:

     defineField({
       name: 'oldField',
       deprecated: { reason: 'Use newField instead' },
       readOnly: true,
       hidden: ({value}) => value === undefined,
       initialValue: undefined
     })
     

3. Migrate (Data)

   • Generate a migration script using @sanity/migrate or standard client patches.
   • Template: Iterate over documents -> patch(doc.id).set({ newField: doc.oldField }).unset(['oldField']).

4. Clean (Delete)

   • Only allow deleting a field definition if the user confirms "I have migrated the data and the field is undefined in all documents."