Split a Markdown file or Markdown text into chunks by heading, for search, embeddings or RAG.

Use this when you need a long Markdown document (docs, notes, a README) broken into pieces that each know where they came from. A chunk never mixes two sections. Each chunk has heading_path (like ["Guide", "Install"]), anchor (the GitHub-style #link), start_line and end_line (1-based, in the file), part and parts (when a big section had to be split), chars and text. Code blocks and tables are kept whole when they fit; when they don't, each piece gets the fence or table header again. Plain code, not AI: same input, same chunks.

Do not use it for PDF or Word files (convert them to Markdown first), to just see the headings (use outline_markdown), or to read one section (use get_section). Sizes are characters, not tokens.

Returns {"source", "total", "start", "chunks": [...], "next_start"}. next_start is null when there are no more chunks.

List every heading in a Markdown file or text, with its level, path, anchor, line number and size.

Use this when you want a quick map of a long document before you read or chunk it, or to find the exact heading or anchor to pass to get_section. Headings inside code blocks and YAML front matter are ignored. Both "# Title" and underlined (=== / ---) headings are found.

Do not use it to get the text itself (use get_section or chunk_markdown).

Returns {"source", "count", "headings": [{"level", "title", "path", "anchor", "line", "end_line", "chars"}]}. chars is the size of that heading's own text, not counting the sections under it.

Return the text of one section of a Markdown file or text, found by heading title or anchor.

Use this when you only need one part of a long document, like the "Install" section of a README, so you don't have to read the whole file. If two headings have the same title, the first one is returned and "matches" tells you how many there are; use the anchor (from outline_markdown) to pick another.

Do not use it to split the whole document (use chunk_markdown).

Returns {"title", "heading_path", "level", "anchor", "start_line", "end_line", "chars", "matches", "text"}. If nothing matches, the error lists the headings.

Split a Markdown file into chunks and save them as a JSONL file (one chunk per line).

Use this when the chunks are going into a search index, vector database or another program, and you want a file instead of a long chat reply. The chunks are the same as chunk_markdown gives. It writes only the one .jsonl file and replaces it if it is already there. It never changes the Markdown file.

Do not use it to look at chunks in the chat (use chunk_markdown).

Returns {"output_path", "chunks", "bytes", "biggest_chunk_chars"}.