Function renderLargeFileMap

src/context/file-outline.ts:125–158

(
  relPath: string,
  content: string,
  opts: { headLines?: number } = {},
)

 * model gets immediate orientation without a second call.
 */
export async function renderLargeFileMap(
  relPath: string,
  content: string,
  opts: { headLines?: number } = {},
): Promise<string> {
  const headLines = opts.headLines ?? 40;
  const allLines = content.split('\n');
  const outline = await fileOutline(relPath, content);

  const head = allLines.slice(0, headLines)
    .map((line, i) => `${String(i + 1).padStart(4, ' ')}\t${line}`)
    .join('\n');

  const parts: string[] = [];
  parts.push(`[LARGE FILE — ${allLines.length} lines. Showing a structural map + the first ${Math.min(headLines, allLines.length)} lines.`);
  parts.push(`Read a specific section with read_file offset=<startLine> limit=<n>, pass symbol="Name" to read one declaration, or grep for a term.]`);
  parts.push('');

  if (outline.length > 0) {
    parts.push('OUTLINE (symbol → lines):');
    for (const e of outline) {
      parts.push(`  ${e.symbol}  —  lines ${e.startLine}-${e.endLine}`);
    }
    parts.push('');
  }

  parts.push(`HEAD (lines 1-${Math.min(headLines, allLines.length)}):`);
  parts.push(head);
  if (allLines.length > headLines) {
    parts.push(`[... ${allLines.length - headLines} more lines below. Use the outline above to jump to a section.]`);
  }

  return parts.join('\n');
}