Answer markers (idk / handoff / chips)

Source: platform/apps/app/src/lib/chat/answer-markers.ts · rendered from main on every deploy — edit in the repo, not here
/**
 * End-of-answer UI marker parser (ADR-0022 rich messages).
 *
 * Two markers share the same `A|B|C` shape:
 *
 *   SUGGESTIONS: — ambient follow-up questions (3 max, up to 100 chars)
 *   BUTTONS:     — discrete choices the assistant is asking the user to
 *                  pick from (6 max, up to 80 chars — chip-sized)
 *   STICKER:     — ADR-0202: one sticker intent (a single token, e.g.
 *                  `thanks`); the channel core maps it to a sticker part.
 *   ATTACH:      — ADR-0208: response-asset ids (`ast_…`, `|`-separated, ≤ 4);
 *                  the server keeps only ids it retrieved for this turn.
 *
 * Markers are stripped from the visible answer; the widget receives them
 * as separate SSE events and renders chip UIs. Keeping the extraction
 * out of the chat handler makes it unit-testable and shareable with any
 * future channel (e.g. a LINE flex-message renderer).
 */

const SUG_MARKER = 'SUGGESTIONS:';
const BTN_MARKER = 'BUTTONS:';
const STK_MARKER = 'STICKER:';
const ATT_MARKER = 'ATTACH:';
const MAX_ATTACH = 4;
const MAX_SUGGESTIONS = 3;
const MAX_BUTTONS = 6;
const MAX_SUGGESTION_LEN = 100;
const MAX_BUTTON_LEN = 80;

export interface AnswerMarkers {
  /** Text with both markers stripped. */
  clean: string;
  suggestions: string[];
  buttons: string[];
  /** Lower-cased sticker intent, or null when the marker is absent/empty. */
  sticker: string | null;
  /** Response-asset ids named after ATTACH: (unvalidated — the caller checks them). */
  attach: string[];
}

export function parseAnswerMarkers(text: string): AnswerMarkers {
  // ATTACH: — a line of ids; lifted first like STICKER:. Brackets the model
  // may copy from the context list ("[ast_x]") are tolerated.
  let attach: string[] = [];
  const attIdx = text.lastIndexOf(ATT_MARKER);
  if (attIdx !== -1) {
    attach = text
      .slice(attIdx + ATT_MARKER.length)
      .split('\n')[0]
      .split('|')
      .map((s) =>
        stripDecor(s)
          .replace(/^\[|\]$/g, '')
          .trim(),
      )
      .filter((s) => /^ast_[A-Za-z0-9_-]{6,32}$/.test(s))
      .slice(0, MAX_ATTACH);
    text = `${text.slice(0, attIdx)}${text.slice(attIdx).split('\n').slice(1).join('\n')}`.replace(
      /[\s*]+$/,
      '',
    );
  }
  // The sticker marker is a single token on the last line; lift it out first
  // so it can't be mistaken for part of a SUGGESTIONS/BUTTONS list.
  let sticker: string | null = null;
  const stkIdx = text.lastIndexOf(STK_MARKER);
  if (stkIdx !== -1) {
    const raw = stripDecor(text.slice(stkIdx + STK_MARKER.length).split('\n')[0]).toLowerCase();
    sticker = /^[a-z_]{1,24}$/.test(raw) ? raw : null;
    text = `${text.slice(0, stkIdx)}${text.slice(stkIdx).split('\n').slice(1).join('\n')}`.replace(
      /[\s*]+$/,
      '',
    );
  }

  const sugIdx = text.indexOf(SUG_MARKER);
  const btnIdx = text.indexOf(BTN_MARKER);

  const extract = (
    startAfter: number,
    nextMarkerIdx: number,
    cap: number,
    maxLen: number,
  ): string[] => {
    const end = nextMarkerIdx === -1 ? text.length : nextMarkerIdx;
    return text
      .slice(startAfter, end)
      .split('|')
      .map((s) => stripDecor(s))
      .filter((s) => s.length > 0 && s.length < maxLen)
      .slice(0, cap);
  };

  const suggestions: string[] =
    sugIdx === -1
      ? []
      : extract(
          sugIdx + SUG_MARKER.length,
          btnIdx > sugIdx ? btnIdx : -1,
          MAX_SUGGESTIONS,
          MAX_SUGGESTION_LEN,
        );

  const buttons: string[] =
    btnIdx === -1
      ? []
      : extract(
          btnIdx + BTN_MARKER.length,
          sugIdx > btnIdx ? sugIdx : -1,
          MAX_BUTTONS,
          MAX_BUTTON_LEN,
        );

  // Visible text ends at whichever marker appears first. Strip any trailing
  // markdown noise the model may have placed before the marker (e.g.
  // `**SUGGESTIONS:**` leaves a dangling `**` in the visible text).
  const present = [sugIdx, btnIdx].filter((i) => i !== -1);
  const cut = present.length > 0 ? Math.min(...present) : -1;
  const clean =
    cut === -1
      ? text
      : text
          .slice(0, cut)
          .replace(/[\s*]+$/, '')
          .trim();

  return { clean, suggestions, buttons, sticker, attach };
}

/** Trim whitespace, surrounding markdown emphasis (`*` / `**`), and surrounding
 * quote chars (straight or curly). Models occasionally wrap the marker as
 * `**SUGGESTIONS:**` or quote each item; both leak garbage characters into the
 * extracted strings if not stripped. */
function stripDecor(s: string): string {
  return s
    .trim()
    .replace(/^\*+|\*+$/g, '')
    .trim()
    .replace(/^["'“”‘’]+|["'“”‘’]+$/g, '')
    .trim();
}