Prompt PebbleAI prompt builder & token estimator

About

About Prompt Pebble

A small set of free tools for people who write prompts for AI assistants: build them, borrow a template, fill in the gaps, count the tokens and split long text to fit.

What is here

  • Prompt builder: turns a role, task, context, constraints, examples and an output format into one tidy prompt, with XML-style tags, Markdown headings or plain labels, and drafts saved in your browser.
  • Prompt templates: 48 original templates for writing, coding, analysis, learning and business, each with variables to fill in.
  • Token counter: exact counts for OpenAI's o200k_base and cl100k_base encodings, a token-by-token view, and a clearly labelled rough estimate for other models.
  • Prompt variable filler: fills the {{variables}} of a template from a form or from CSV rows.
  • Text chunker: splits long text by tokens, characters or words, with overlap, at natural breaks.

How it works

Every tool runs in your browser. What you type, paste or open is processed on your device and is not uploaded; there are no accounts and no cookies. The token counter and the chunker download OpenAI's encoding tables from this site the first time you need them, then work offline. Prompt drafts you save in the builder stay in your browser's local storage until you delete them. The privacy page lists exactly what is stored and the one analytics service the site uses.

Honest limits

Token counts are exact only for the two OpenAI encodings named on the counter. Every other figure is labelled as an estimate. The prompt builder and the templates arrange your words; they cannot promise a particular answer from any model, so always check what an assistant writes before you rely on it.

Credits

The templates, examples and explanations on this site were written for it. Tokenizing uses the gpt-tokenizer library by Bazyli Brzoska (MIT licence), a JavaScript port of OpenAI's tiktoken encodings. Icons are from Lucide (ISC licence). The typefaces are Marcellus, Be Vietnam Pro and Noto Sans Mono, all under the SIL Open Font License and served from this site.