# Writing Rhythm

> See sentence lengths, paragraph pacing and differences between two drafts. Explore sentence and paragraph pacing with language-aware boundaries, source spans, distributions and a measured comparison with a second draft.

Part of usefulweb.app (https://usefulweb.app/). Part of [Paperwell](https://paperwell.usefulweb.app/) (ownerApp: paperwell). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://paperwellwritingrhythm.usefulweb.app/ (interactive tool at https://paperwellwritingrhythm.usefulweb.app/tool)
- JSON API: POST https://paperwellwritingrhythm.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://paperwellwritingrhythm.usefulweb.app/api/v1/tool)
- OpenAPI: https://paperwellwritingrhythm.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://paperwellwritingrhythm.usefulweb.app/mcp - tool `paperwell_writing_rhythm`

## Inputs
- text (textarea): Draft
- compare (textarea): Second draft (optional)
- locale (select): Analysis language
- wpm (number): Modeled reading speed (words/minute)

## Method
- Intl.Segmenter uses the selected language for sentence boundaries; line breaks remain explicit boundaries. Unicode word tokens, exact source offsets and paragraph membership are retained.
- Charts cover the complete draft and use the full word-count scale. Longer drafts group consecutive sentences and show the minimum, maximum and mean; individual ranges remain available in the browser. Modeled reading time uses your chosen words per minute. Lengths and distributions support editing decisions; they are not a writing-quality score. Ambiguous abbreviations can still need human review.