letter_preview

Renders a letter, draft or form as images, composed like a real send, and returns inline PNGs, PDF link, page count, cost and designRender with the actual documentMode, rendered letter chrome and bodyStartMm. The preview is free and the letter stays put. The letter comes via letterId, a released template (templateId, templateVersionId, templateMergeValues) or inline content OR blocks; the recipient via recipientAddressId or the recipient fields. With letterId, the embedded card is the human preview; the PDF link and letter text are also in the result, for text-only views. An unsaved design applies to this one preview only. Standalone forms (self-declaration, questionnaire, certificate) render as a form with design: { "schemaVersion": 1, "documentMode": "form" }: that drops recipient block, date and subject and starts content at 27 mm. Schema reference: frankki://blocks-guide. For a rebuild of an original, the PNGs show page by page whether page count and major geometry match; changed blocks or a changed design render again on the next letter_preview call. template_save stores the matching layout as a draft, template_release releases it.

Input contract

Contract-shaped example

letter_preview({
  "letterId": "LETTER_ID_FROM_DRAFT",
  "pages": 8,
  "resolution": "full"
})

Inspect every rendered page. If the draft is correct, call shipping_quote immediately before submission.

For conditional fields and nested object limits, the generated complete tool reference remains authoritative. See errors and safe agent onboarding before implementing retries or a live send.