Checkpoint: Batch Folder Converter

No new API, just the loop

This lesson doesn't introduce anything new from MarkItDown's side, it's the checkpoint: prove Lessons 1-4 add up to something useful by converting an entire folder of mixed-format files with the same .convert(path) call, one iteration per file, writing real .md files to disk.

This is close to the actual shape of a real ingestion script: point it at a directory, convert what's there, get Markdown out the other side, ready to chunk, embed, or feed straight into a prompt.

Why office_notice.png is skipped here

The fixtures folder has six files, this lesson only converts five. office_notice.png is left out on purpose: MarkItDown's image converter, without an LLM client attached, has nothing to extract from a photo beyond basic file metadata, there's no OCR or vision model running by default. Converting it here would just print noise. Lesson 6 revisits this exact file and shows the same conversion with an LLM client wired in, where the difference becomes the whole point of the lesson.

The code, piece by piece

source_files = sorted(
    p for p in FIXTURES_DIR.iterdir() if p.is_file() and p.name not in SKIP
)

Lists every file in fixtures/ except the skipped one, sorted for deterministic output ordering.

for source_path in source_files:
    result = md.convert(source_path)
    output_path = OUTPUT_DIR / f"{source_path.stem}.md"
    output_path.write_text(result.markdown, encoding="utf-8")
    summary.append((source_path.name, source_path.suffix, len(result.markdown)))

Same .convert() call from every prior lesson, now in a loop, with each result written to a same-named .md file in a local converted/ folder, and a (name, format, length) tuple kept for the summary table.