Variable: AttachmentEventSchema

const AttachmentEventSchema: ZodObject<{ attachment_id: ZodOptional<ZodString>; attachment_type: ZodCustom<AttachmentType, AttachmentType>; conversation_id: ZodOptional<ZodString>; index: ZodNumber; message_id: ZodOptional<ZodString>; space_id: ZodString; type: ZodLiteral<"attachment">; }, $strip>

A new attachment slot appeared in message.attachments[]. Fires exactly once per attachment (matched by attachment_id, positionally for anonymous attachments) the first time we see it. The slot’s payload kind lands in attachment_type so the outer type discriminator stays unambiguous.