Function tryGetPDFReference

src/utils/attachments.ts:3068–3100

(
  filename: string,
)

 * (more than PDF_AT_MENTION_INLINE_THRESHOLD pages), or null otherwise.
 */
export async function tryGetPDFReference(
  filename: string,
): Promise<PDFReferenceAttachment | null> {
  const ext = parse(filename).ext.toLowerCase()
  if (!isPDFExtension(ext)) {
    return null
  }
  try {
    const [stats, pageCount] = await Promise.all([
      getFsImplementation().stat(filename),
      getPDFPageCount(filename),
    ])
    // Use page count if available, otherwise fall back to size heuristic (~100KB per page)
    const effectivePageCount = pageCount ?? Math.ceil(stats.size / (100 * 1024))
    if (effectivePageCount > PDF_AT_MENTION_INLINE_THRESHOLD) {
      logEvent('tengu_pdf_reference_attachment', {
        pageCount: effectivePageCount,
        fileSize: stats.size,
        hadPdfinfo: pageCount !== null,
      } as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS)
      return {
        type: 'pdf_reference',
        filename,
        pageCount: effectivePageCount,
        fileSize: stats.size,
        displayPath: relative(getCwd(), filename),
      }
    }
  } catch {
    // If we can't stat the file, return null to proceed with normal reading
  }
  return null
}

export async function generateFileAttachment(
  filename: string,