apfelpad

A formula notepad for thinking. On-device AI as a first-class function, like =SUM but for language.

Download for macOS brew install Arthur-Ficial/tap/apfelpad

$apfelpad showing a =math formula rendered inline in a pale-green span$

What is it?

Type =apfel("a love letter", 42) anywhere in a markdown document. Press Return. The formula evaluates on your Mac using Foundation Models, streams the result inline in a light-green span, and caches it deterministically so re-runs return the same output. Compose with other formulas: =apfel("summarize", =ref(@intro)). Drop in arithmetic: =math(365*24).

Markdown underneath. 100% local. No API keys. Nothing leaves your Mac.

The formulas

=apfel(prompt, seed?) — on-device LLM call, auto-scoped context
=math(expression) — pure arithmetic, no model
=ref(@anchor) — insert content of a named block
=count(@anchor?) — word count
=date(format?) — current date
=clip() — current clipboard snapshot
=file(path) — local file content (sandboxed)

Auto-quoting: type =apfel(hello world) and apfelpad canonicalises it to =apfel("hello world"). Type English. apfelpad handles the parser.

Requirements

macOS 26 (Tahoe) or later
Apple Silicon (M1 or later)
Apple Intelligence enabled
apfel on PATH (bundled in Homebrew builds)

Privacy

apfelpad makes one network call and it is not for inference: an optional check against api.github.com for new apfelpad releases (togglable in settings). Every language-model call goes to localhost:11450 where apfel --serve runs on your machine, reading from the on-device Foundation Models framework. Documents are plain markdown files on your disk. No telemetry. No accounts. No cloud inference. Ever.