What people find when they search for a prompt optimizer

Anvyll is a Windows prompt optimizer: Ctrl+Space opens a tray overlay on the focused text field. There is no API key to paste. It is not the supply-chain product Anvyl and not Anvil. If you need macOS, Linux, or a tab you can open on any computer, this is the wrong product.

A search for "prompt optimizer" mostly returns three kinds of thing: an open-source web app you paste into, a browser extension that rewrites inside the browser, and the chat box you already have. Anvyll is a fourth shape. It does not ask you to leave the field you were typing in.

How is Anvyll different from linshenkx/prompt-optimizer?

The linshenkx/prompt-optimizer project describes itself as a prompt optimization tool with four usage methods: a web application, a desktop application, a Chrome extension, and Docker. Its README says processing is client-side, with the browser or app talking to AI providers directly, and that you bring those providers in. That description was current on the project's README on 21 September 2026.

Anvyll does not work that way. It is a Windows tray overlay. Capture and Apply use the focused field. Refining does not stay on your machine. When you press Generate, the submitted prompt and any context you attached are sent to the Anvyll service, which calls the model and returns the result.

This page does not compare prices or feature checklists. The README does not publish a price, and a price remembered from somewhere else would be a guess.

What about a browser extension?

An extension rewrites inside the browser, on pages it can see. Anvyll's overlay is not limited to the browser. It is limited to Windows, and to a text field the capture path can read. If the field blocks insertion, the refined text stays on the clipboard. That is a Windows behavior, not an extension permission.

What if I just paste into the chat?

Pasting into the chat is the baseline with no extra product. You write the structure yourself, in whatever window the model lives in. Anvyll's target picker does not open that window. It selects which documented prompting methodology shapes the rewrite, then Apply tries to put the result back in the field you started from.

Where does the text go?

Your product data lives in a local vault. Prompts, sessions and project context are stored in a per-account vault on your own machine, not in a server-side content database.
Refining sends the prompt for processing. When you press Generate, the submitted prompt and any context you attached are sent to the Anvyll service, which calls the model and returns the result.
Account and billing are handled separately. Sign-in, plan and credit records are account data. They are kept apart from the text you refine.