SilverBullet uses JSON Schema for validation of structured data. Schemas ensure that Frontmatter attributes, tag fields, and configuration options conform to expected types and shapes.

Where schemas are used

Tag definitions

When you define a tag with tag.define, you can provide a schema that describes the expected attributes. The schemas of the built-in tags are defined the same way, in ^Library/Std/Infrastructure/Root Tags. SilverBullet validates objects against this schema and surfaces errors in the editor:

tag.define {
  name = "contact",
  schema = {
    type = "object",
    properties = {
      email = schema.string(),
      phone = schema.nullable("string"),
      priority = schema.number(),
    }
  }
}

Pages or objects tagged with #contact will be validated against this schema — if a field has the wrong type, you’ll see a lint warning in the editor.

Configuration definitions

The config.define function uses schemas to validate configuration values:

config.define("myLibrary.config", {
  type = "object",
  properties = {
    enabled = schema.boolean(),
    maxItems = schema.number(),
  }
})

This ensures that config.set("myLibrary.config", ...) only accepts values matching the schema.

Schema helper functions

The ^Library/Std/APIs/Schema library provides convenience functions like schema.string(), schema.number(), schema.array(typ), etc. for building JSON Schema objects in Lua. See the API page for the full list.

References

schema.ref("person") describes a reference: a single quoted wikilink such as owner: "[[Person/Alice]]", pointing at a page or at an object with an anchor ("[[$alice]]").

How validation surfaces

When schema validation fails for page and attributes, SilverBullet shows the error as a lint warning in the editor.