Your Key · Your Model · Checked Before You Download

Change a Model, Without Leaving the Page

The enhancement protocol this site publishes, run here instead of pasted into a chat window. You bring the key; the browser talks to the provider directly. What comes back is put through the real checker before you are offered it.

Change a model with your own key

Read this before you paste a key. This site is static — there is no server here, so your key is not sent to us and could not be even if we wanted it. It is held in your browser and attached to a request that goes straight to the provider.

That also means the usual protection is off: a key in a web page is exposed to anything that can run script on that page. Use a key you can revoke, give it a spending limit, and revoke it when you are done. If that is not a trade you want to make, the prompt on Try It Yourself does the same job in a chat window you already trust, with no key anywhere.

Nothing about your key, your model or your instruction is recorded. Privacy policy →

1 · Your key

Get a Claude key · runs Claude Opus 5

2 · Your model

nothing loaded

Or start from one this site publishes:

3 · The change

The result

The whole file comes back, not a patch — that is what the protocol asks for, so there is nothing for you to merge by hand.

What this actually does

It is the protocol for changing a model, run in one pass in this tab:

  1. That protocol — the whole language reference, byte for byte the same as the one you would paste into a chat window — becomes the system prompt.
  2. Your model and your instruction become the message.
  3. The reply is stripped to its Mermaid and put through the published checker.
  4. A download appears only if that check finds no errors.

Step four is the reason this page exists rather than a chat window. Any assistant will hand you back a model; what this site has that they do not is the validator the generator itself runs, so a file that would be refused is caught here instead of three steps later.

The protocol is about 43,000 tokens and is sent on every request, so a large model costs a few tens of cents a change. On Claude it is cached after the first call, which makes the ones after it markedly cheaper.

If you would rather not paste a key

Nothing here is exclusive to this page. Try It Yourself carries the same protocol as a prompt for a chat window you already pay for, and chapter 11 runs the same checker on whatever comes back. This page only saves the copying.