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Released: August 6, 2026 The /answer endpoint now takes a system_prompt parameter: a plain string that steers how the answer is presented. It is the /answer equivalent of a system message on a chat API — subordinate to Seltz’s own instructions, so the grounding contract and citations stay in force while tone, voice, and format follow yours.

Highlights

  • New system_prompt parameter — a plain string, no schema or wrapper object
  • Presentation only — Retrieval is untouched: the same sources are searched and cited
  • Composes — Works alongside response_format, on seltz-base and seltz-pro, buffered and streaming
  • Forgiving default — Empty or whitespace-only behaves exactly as if the field were omitted
  • Bounded — Capped at 8 KiB of UTF-8; a longer value is rejected with a 400 naming the field, and not billed
  • Available everywhere — Python SDK 1.8.0, TypeScript SDK 2.6.0, and REST POST /v1/answer

Quick Start

Good to Know

system_prompt is steering, not a guarantee — use it to shape output you asked for, not to enforce a rule. Where your instructions conflict directly with Seltz’s own, Seltz’s win: asking for plain text, for example, may still yield Markdown.

Get Started

View the answer endpoint documentation